An earthquake happens when two blocks of the earth suddenly slip past one another. Earthquakes strike suddenly, violently, and without warning at any time of the day or night. If an earthquake occurs in a populated area, it may cause property damage, injuries, and even deaths. If you live in a coastal area, there is the possibility of a tsunami. Damage from earthquakes can also lead to floods or fires.

Although there are no guarantees of safety during an earthquake, you can take actions to protect yourself. You should have a disaster plan. Being prepared can help reduce fear, anxiety, and losses. If you do experience a disaster, it is normal to feel stressed. You may need help in finding ways to cope.

What is an earthquake? 

An earthquake is what happens when two blocks of the earth suddenly slip past one another. The surface where they slip is called the fault or fault plane. The location below the earth’s surface where the earthquake starts is called the hypocenter, and the location directly above it on the surface of the earth is called the epicenter.

Sometimes an earthquake has foreshocks. These are smaller earthquakes that happen in the same place as the larger earthquake that follows. Scientists can’t tell that an earthquake is a foreshock until the larger earthquake happens. The largest, main earthquake is called the mainshock. Mainshocks always have aftershocks that follow. These are smaller earthquakes that occur afterwards in the same place as the mainshock. Depending on the size of the mainshock, aftershocks can continue for weeks, months, and even years after the mainshock!

What causes earthquakes and where do they happen?

The earth has four major layers: the inner core, outer core, mantle and crust. The crust and the top of the mantle make up a thin skin on the surface of our planet.

But this skin is not all in one piece – it is made up of many pieces like a puzzle covering the surface of the earth. Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries. The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving. Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.

Why does the earth shake when there is an earthquake?

While the edges of faults are stuck together, and the rest of the block is moving, the energy that would normally cause the blocks to slide past one another is being stored up. When the force of the moving blocks finally overcomes the friction of the jagged edges of the fault and it unsticks, all that stored up energy is released. The energy radiates outward from the fault in all directions in the form of seismic waves like ripples on a pond. The seismic waves shake the earth as they move through it, and when the waves reach the earth’s surface, they shake the ground and anything on it, like our houses and us!

How are earthquakes recorded?

Earthquakes are recorded by instruments called seismographs. The recording they make is called a seismogram. The seismograph has a base that sets firmly in the ground, and a heavy weight that hangs free. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. Instead the spring or string that it is hanging from absorbs all the movement. The difference in position between the shaking part of the seismograph and the motionless part is what is recorded.

How do scientists measure the size of earthquakes?

The size of an earthquake depends on the size of the fault and the amount of slip on the fault, but that’s not something scientists can simply measure with a measuring tape since faults are many kilometers deep beneath the earth’s surface. So how do they measure an earthquake? They use the seismogram recordings made on the seismographs at the surface of the earth to determine how large the earthquake was (figure 5). A short wiggly line that doesn’t wiggle very much means a small earthquake, and a long wiggly line that wiggles a lot means a large earthquake. The length of the wiggle depends on the size of the fault, and the size of the wiggle depends on the amount of slip.

The size of the earthquake is called its magnitude. There is one magnitude for each earthquake. Scientists also talk about theintensity of shaking from an earthquake, and this varies depending on where you are during the earthquake.

How can scientists tell where the earthquake happened?

Seismograms come in handy for locating earthquakes too, and being able to see the P wave and the S wave is important. You learned how P & S waves each shake the ground in different ways as they travel through it. P waves are also faster than S waves, and this fact is what allows us to tell where an earthquake was. To understand how this works, let’s compare P and S waves to lightning and thunder. Light travels faster than sound, so during a thunderstorm you will first see the lightning and then you will hear the thunder. If you are close to the lightning, the thunder will boom right after the lightning, but if you are far away from the lightning, you can count several seconds before you hear the thunder. The further you are from the storm, the longer it will take between the lightning and the thunder.

P waves are like the lightning, and S waves are like the thunder. The P waves travel faster and shake the ground where you are first. Then the S waves follow and shake the ground also. If you are close to the earthquake, the P and S wave will come one right after the other, but if you are far away, there will be more time between the two.

By looking at the amount of time between the P and S wave on a seismogram recorded on a seismograph, scientists can tell how far away the earthquake was from that location. However, they can’t tell in what direction from the seismograph the earthquake was, only how far away it was. If they draw a circle on a map around the station where the radius of the circle is the determined distance to the earthquake, they know the earthquake lies somewhere on the circle. But where?

Scientists then use a method called triangulation to determine exactly where the earthquake was (see image below). It is called triangulation because a triangle has three sides, and it takes three seismographs to locate an earthquake. If you draw a circle on a map around three different seismographs where the radius of each is the distance from that station to the earthquake, the intersection of those three circles is the epicenter!

Can scientists predict earthquakes?

No, and it is unlikely they will ever be able to predict them. Scientists have tried many different ways of predicting earthquakes, but none have been successful. On any particular fault, scientists know there will be another earthquake sometime in the future, but they have no way of telling when it will happen.

Is there such a thing as earthquake weather? Can some animals or people tell when an earthquake is about to hit?

These are two questions that do not yet have definite answers. If weather does affect earthquake occurrence, or if some animals or people can tell when an earthquake is coming, we do not yet understand how it works.

Originally written by Lisa Wald (U.S. Geological Survey) for “The Green Frog News”

An earthquake is caused by a sudden slip on a fault. A fault is a fracture or zone of fractures between two blocks of rock.

During an earthquake, the rock on one side of the fault suddenly slips with relative to the other. The faults are most commonly found around the edge of plates which are continental-size blocks of rocks that comprise the outermost part of the earth.

These plates are constantly moving (albeit very slowly) at rates up to four inches per year (10 cm/yr) although most rates of travel are considerably less. Also, the rate of travel varies at different locations within each plate.

At the boundary where plates are colliding, one plate is forced under the other plate forming deep trenches. Where plates are moving apart, mountain ridges form.

Since large geological forces are at work near these plate boundaries, it stand to reason that these boundaries are where the majority of earthquakes occur.

How these tectonic plates move relative to each other determines the type of fault that exists at their junction point. There are three basic types of faults; normal, reverse and strike-slip.

The junction where plates are moving away from each other produces a "normal" fault. It is not normal in the sense of it being common as it is not the most common. The word "normal" refers to the usually very steep fault plane between two blocks of earth.

In a normal fault, the two blocks are pulling away from one another causing one of the fault blocks to slip upward and the other downward with respect to the fault plane.

If the two blocks of earth are moving toward each other, the resulting fault is called a reverse fault. This is where one block of earth is forced up and over (or one is forced under) the opposing block. In either case, there is a change in the height of one or both blocks of earth.

A third fault is called the strike-slip fault. In strike-slip faults the opposing blocks of earth move horizontally opposite to each other. There is no (or very little) vertical movement.

There are also combinations of these basic fault movements as the land can move both horizontally and vertically. However, there is no way to telling the type of fault movement until well after the event is over.

While any of these three faults can produce extensive damage on land, the reverse fault is the source of most tsunamis.

The scale by which earthquakes are rated is called the Moment Magnitude scale (M_w). It is a measure of the distance a fault moved and the force required to move it.

The Moment Magnitude scale values are logarithmic meaning that with each increase in whole value the amplitude of the ground motion increase by ten. For example, a magnitude 5.0 earthquake is ten times as powerful as a magnitude 4.0 earthquake.

For a magnitude 6.0 earthquake, it is ten times more powerful than a magnitude 5.0 quake but is 100 times stronger than a magnitude 4.0 event.

This logarithmic increase in released energy at the 'strong' and 'great' earthquake levels means that minor increases in magnitude indicate huge jumps in released energy. According to the U.S. Geological Survey, the December 26, 2004 Sumatra earthquake measured a magnitude 9.1.

Three months later, March 28, 2005, another 'great' earthquake occurred on the same fault line as with the earlier quake and measured a magnitude 8.7.

Despite the seemingly small 0.4 difference in magnitude, due to the logarithmic values, the December magnitude 9.1 earthquake was 2½ times MORE powerful than the March 2005 earthquake (and over 125,000 times as powerful as a magnitude 4.0 quake).

Earthquake magnitude, energy release, and shaking intensity are all related measurements of an earthquake that are often confused with one another. Their dependencies and relationships can be complicated, and even one of these concepts alone can be confusing.

Here we'll look at each of these, as well as their interconnectedness and dependencies.

Magnitude

The time, location, and magnitude of an earthquake can be determined from the data recorded by seismometer. Seismometers record the vibrations from earthquakes that travel through the Earth. Each seismometer records the shaking of the ground directly beneath it. Sensitive instruments, which greatly magnify these ground motions, can detect strong earthquakes from sources anywhere in the world. Modern systems precisely amplify and record ground motion (typically at periods of between 0.1 and 100 seconds) as a function of time.

Magnitude is the size of the earthquake. An earthquake has a single magnitude. The shaking that it causes has many values that vary from place to place based on distance, type of surface material, and other factors. See the Intensity section below for more details on shaking intensity measurements.

Types of Magnitudes

Magnitude is expressed in whole numbers and decimal fractions. For example, a magnitude 5.3 is a moderate earthquake, and a 6.3 is a strong earthquake. Because of the logarithmic basis of the scale, each whole number increase in magnitude represents a tenfold increase in measured amplitude as measured on a seismogram.

When initially developed, all magnitude scales based on measurements of the recorded waveform amplitudes were thought to be equivalent. But for very large earthquakes, some magnitudes underestimate true earthquake size, and some underestimate the size. Thus, we now use measurements that describe the physical effects of an earthquake rather than measurements based only on the amplitude of a waveform recording. More on that later.

The Richter Scale (M_L) is what most people have heard about, but in practice it is not commonly used anymore, except for small earthquakes recorded locally, for which ML and short-period surface wave magnitude (Mblg) are the only magnitudes that can be measured. For all other earthquakes, the moment magnitude (M_w) scale is a more accurate measure of the earthquake size.

Although similar seismographs had existed since the 1890's, it was only in 1935 that Charles F. Richter, a seismologist at the California Institute of Technology, introduced the concept of earthquake magnitude. His original definition held only for California earthquakes occurring within 600 km of a particular type of seismograph (the Woods-Anderson torsion instrument). His basic idea was quite simple: by knowing the distance from a seismograph to an earthquake and observing the maximum signal amplitude recorded on the seismograph, an empirical quantitative ranking of the earthquake's inherent size or strength could be made. Most California earthquakes occur within the top 16 km of the crust; to a first approximation, corrections for variations in earthquake focal depth were, therefore, unnecessary.

The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included for the variation in the distance between the various seismographs and the epicenter of the earthquakes.

Moment Magnitude (M_W) is based on physical properties of the earthquake derived from an analysis of all the waveforms recorded from the shaking. First the seismic moment is computed, and then it is converted to a magnitude designed to be roughly equal to the Richter Scale in the magnitude range where they overlap.

         Moment (M_O) = rigidity x area x slip

where rigidity is the strength of the rock along the fault, area is the area of the fault that slipped, and slip is the distance the fault moved. Thus, stronger rock material, or a larger area, or more movement in an earthquake will all contribute to produce a larger magnitude.

Then,

         Moment Magnitude (M_W) = 2/3 log₁₀(M_O) - 9.1

Energy Release

Another way to measure the size of an earthquake is to compute how much energy it released. The amount of energy radiated by an earthquake is a measure of the potential for damage to man-made structures. An earthquake releases energy at many frequencies, and in order to compute an accurate value, you have to include all frequencies of shaking for the entire event.

While each whole number increase in magnitude represents a tenfold increase in the measured amplitude, it represents an 32 times more energy release.

The energy can be converted into yet another magnitude type called the Energy Magnitude (M_e). However, since the Energy Magnitude and Moment Magnitude measure two different properties of the earthquake, their values are not the same.

The energy release can also be roughly estimated by converting the moment magnitude, M_w, to energy using the equation log E = 5.24 + 1.44M_w, where M_w is the moment magnitude.

Intensity

Whereas the magnitude of an earthquake is one value that describes the size, there are many intensity values for each earthquake that are distributed across the geographic area around the earthquake epicenter. The intensity is the measure of shaking at each location, and this varies from place to place, depending mostly on the distance from the fault rupture area. However, there are many more aspects of the earthquake and the ground it shakes that affect the intensity at each location, such as what direction the earthquake ruptured, and what type of surface geology is directly beneath you. Intensities are expressed in Roman numerals, for example, VI, X, etc.

Traditionally the intensity is a subjective measure derived from human observations and reports of felt shaking and damage. The data used to be gathered from postal questionnaires, but with the advent of the internet, it's now collected using a web-based form. However, instrumental data at each station location can be used to calculate an estimated intensity.

The intensity scale that we use in the United States is called the Modified Mercalli Intensity Scale, but other countries use other scales.

Examples

These examples illustrate how locations (and depth), magnitudes, intensity, and faults (and rupture) characteristics are dependent and related.

Intensity of Shaking Depends on the Local Geology

Intensity of Shaking Depends on Depth of the Earthquake

The shaking from the M6.7 Northridge, CA earthquake was more intense and covered a wider area than the slightly larger M6.8 Nisqually, WA earthquake.

The reason is shown by the two cartoon cross-sections below. There was more shaking in the Northridge earthquake because the earthquake occurred closer to the surface (3-11 miles), as opposed to the Nisqually earthquake's deeper hypocenter (30-36 miles).

Moment Release (Energy) of Many Small Earthquakes vs. One Large Earthquake

The small- and moderate-size earthquakes that occur frequently around the world release far less energy that a single great earthquake.

What Would it Take to Make a Magnitude N Earthquake?

If we sum all of the energy release from all of the earthquakes over the past ~110 years, the equivalent magnitude ~ M_w9.95.

If the San Andreas Fault were to rupture end-to-end (~1400km), with ~10m of average slip, it would produce an earthquake of M_w 8.47.

If the South American subduction zone were to rupture end-to-end (~6400km), with ~40m of average slip, it would produce an earthquake of M_w 9.86.

You would need ~14,000km fault length, with a seismogenic thickness averaging 40km (width of 100km), to slip and average of 30m to produce an M_w 10.

You would need ~80,000km of fault length with an average seismogenic width of 100km to produce an M_w10.5. All of the subduction zones in the World, plus some adjoining structures amount to ~40,000km, and the circumference of the Earth is ~40,000km, so an M_w 10.5 is highly unlikely.

 Thanks to Gavin Hayes and David Wald for providing much of the material for this page.

The earliest reference we have to unusual animal behavior prior to a significant earthquake is from Greece in 373 BC. Rats, weasels, snakes, and centipedes reportedly left their homes and headed for safety several days before a destructive earthquake. Anecdotal evidence abounds of animals, fish, birds, reptiles, and insects exhibiting strange behavior anywhere from weeks to seconds before an earthquake. However, consistent and reliable behavior prior to seismic events, and a mechanism explaining how it could work, still eludes us. Most, but not all, scientists pursuing this mystery are in China or Japan.

We can easily explain the cause of unusual animal behavior seconds before humans feel an earthquake. Very few humans notice the smaller P wave that travels the fastest from the earthquake source and arrives before the larger S wave. But many animals with more keen senses are able to feel the P wave seconds before the S wave arrives. As for sensing an impending earthquake days or weeks before it occurs, that's a different story.

A once popular theory purported that there was a correlation between Lost Pet ads in the San Jose Mercury News and the dates of earthquakes in the San Francisco Bay area. A thorough statistical analysis of this theory, published in California Geology in 1988, concluded that there was no such correlation, however.

Another paper published in a scientific journal in the U.S. on this subject by a respected scientist in 2000 is summarized here...

The paper poses this question: Is it reasonable for a seismic-escape behavior pattern to evolve, and can such a genetic system be maintained in the face of selection pressures operating on the time scales of damaging seismic events? All animals instinctively respond to escape from predators and to preserve their lives. A wide variety of vertebrates already express “early warning” behaviors that we understand for other types of events, so it’s possible that a seismic-escape response could have evolved from this already-existing genetic predisposal. An instinctive response following a P-wave seconds before a larger S wave is not a “huge leap”, so to speak, but what about other precursors that may occur days or weeks before an earthquake that we don’t yet know about? If in fact there are precursors to a significant earthquake that we have yet to learn about (such as ground tilting, groundwater changes, electrical or magnetic field variations), indeed it’s possible that some animals could sense these signals and connect the perception with an impending earthquake.

However, much research still needs to be done on this subject. The author suggests establishing a baseline behavior pattern that can be compared with reactions of various environmental stimuli, and then testing various potential stimuli in the laboratory. Of course, the presence of these stimuli still needs to be researched with regard to precursory phenomena preceding an earthquake, for if these signals aren’t present in the environment before an earthquake, a connection is irrelevant.

Find some interesting facts about earthquakes.

• The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964 UTC.

• The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960.

• The earliest reported earthquake in California was felt in 1769 by the exploring expedition of Gaspar de Portola while the group was camping about 48 kilometers (30 miles) southeast of Los Angeles.

• Before electronics allowed recordings of large earthquakes, scientists built large spring-pendulum seismometers in an attempt to record the long-period motion produced by such quakes. The largest one weighed about 15 tons. There is a medium-sized one three stories high in Mexico City that is still in operation.

• The fastest wave, and therefore the first to arrive at a given location, is called the P wave. The P wave, or compressional wave, alternately compresses and expands material in the same direction it is traveling.

• The average rate of motion across the San Andreas Fault Zone during the past 3 million years is 56 mm/yr (2 in/yr). This is about the same rate at which your fingernails grow. Assuming this rate continues, scientists project that Los Angeles and San Francisco will be adjacent to one another in approximately 15 million years.

• The East African Rift System is a 50-60 km (31-37 miles) wide zone of active volcanics and faulting that extends north-south in eastern Africa for more than 3000 km (1864 miles) from Ethiopia in the north to Zambezi in the south. It is a rare example of an active continental rift zone, where a continental plate is attempting to split into two plates which are moving away from one another.

• The first “pendulum seismoscope” to measure the shaking of the ground during an earthquake was developed in 1751, and it wasn’t until 1855 that faults were recognized as the source of earthquakes.

• Moonquakes (“earthquakes” on the moon) do occur, but they happen less frequently and have smaller magnitudes than earthquakes on the Earth. It appears they are related to the tidal stresses associated with the varying distance between the Earth and Moon. They also occur at great depth, about halfway between the surface and the center of the moon.

• Although both are sea waves, a tsunami and a tidal wave are two different unrelated phenomenona. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. A tsunami is a sea wave caused by an underwater earthquake or landslide (usually triggered by an earthquake) displacing the ocean water.

• The hypocenter of an earthquake is the location beneath the earth’s surface where the rupture of the fault begins.

• The epicenter of an earthquake is the location directly above the hypocenter on the surface of the earth.

• The “Ring of Fire” also called the Circum-Pacific belt, is the zone of earthquakes surrounding the Pacific Ocean — about 90% of the world’s earthquakes occur there. The next most seismic region (5-6% of earthquakes) is the Alpide belt (extends from Mediterranean region, eastward through Turkey, Iran, and northern India.

• It is estimated that there are 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and 100 of them cause damage.

• It is thought that more damage was done by the resulting fire after the 1906 San Francisco earthquake than by the earthquake itself.

• A seiche (pronounced SAYSH) is what happens in the swimming pools of Californians during and after an earthquake. It is “an internal wave oscillating in a body of water” or, in other words, it is the sloshing of the water in your swimming pool, or any body of water, caused by the ground shaking in an earthquake. It may continue for a few moments or hours, long after the generating force is gone. A seiche can also be caused by wind or tides.

• Each year the southern California area has about 10,000 earthquakes. Most of them are so small that they are not felt. Only several hundred are greater than magnitude 3.0, and only about 15-20 are greater than magnitude 4.0. If there is a large earthquake, however, the aftershock sequence will produce many more earthquakes of all magnitudes for many months.

• The magnitude of an earthquake is a measured value of the earthquake size. The magnitude is the same no matter where you are, or how strong or weak the shaking was in various locations. The intensity of an earthquake is a measure of the shaking created by the earthquake, and this value does vary with location.

• The Wasatch Range, with its outstanding ski areas, runs North-South through Utah, and like all mountain ranges it was produced by a series of earthquakes. The 386 km (240-mile)-long Wasatch Fault is made up of several segments, each capable of producing up to a M7.5 earthquake. During the past 6,000 years, there has been a M6.5+ about once every 350 years, and it has been about 350 years since the last powerful earthquake, which was on the Nephi segment.

• The world’s greatest land mountain range is the Himalaya-Karakoram. It countains 96 of the world’s 109 peaks of over 7,317m (24,000 ft). The longest range is the Andes of South America which is 7,564km (4700 mi) in length. Both were created by the movement of tectonic plates.

• The longest mountain range in the world, though, is the mid-ocean ridge, extending 64,374 km (40,000 mi) from the Arctic Ocean to the Atlantic Ocean, around Africa, Asia, and Australia, and under the Pacific Ocean to the west coast of North America.

• As far as we know, there is no such thing as "earthquake weather". Statistically, there is an equal distribution of earthquakes in cold weather, hot weather, rainy weather, etc. If weather does affect earthquake occurrence, we do not yet understand how it works.

• From 1975-1995 there were only four states that did not have any earthquakes. They were: Florida, Iowa, North Dakota, and Wisconsin.

• The core of the earth was the first internal structural element to be identified. In 1906 R.D. Oldham discovered it from his studies of earthquake records. The inner core is solid, and the outer core is liquid and so does not transmit the shear wave energy released during an earthquake.

• The swimming pool at the University of Arizona in Tucson lost water from sloshing (seiche) caused by the 1985 M8.1 Michoacan, Mexico earthquake 2000 km (1240 miles) away.

• Earthquakes occur in the central portion of the United States too! Some very powerful earthquakes occurred along the New Madrid fault in the Mississippi Valley in 1811-1812. Because of the crustal structure in the Central US which efficiently propagates seismic energy, shaking from earthquakes in this part of the country are felt at a much greater distance from the epicenters than similar size quakes in the Western US.

• Most earthquakes occur at depths of less than 80 km (50 miles) from the Earth’s surface.

• The San Andreas fault is NOT a single, continuous fault, but rather is actually a fault zone made up of many segments. Movement may occur along any of the many fault segments along the zone at any time. The San Andreas fault system is more that 1300 km (800 miles) long, and in some spots is as much as 16 km (10 miles) deep.

• The origin of the name of the San Andreas Fault is often cited as the San Andreas Lake. However, based on some 1895 and 1908 reports by geologist A.C. Lawson, who named the fault, the name was actually taken from the San Andreas Valley. He likely did not realize at the time that the fault ran almost the entire length of California!

• The world’s deadliest recorded earthquake occurred in 1556 in central China. It struck a region where most people lived in caves carved from soft rock. These dwellings collapsed during the earthquake, killing an estimated 830,000 people. In 1976 another deadly earthquake struck in Tangshan, China, where more than 250,000 people were killed.

• Florida and North Dakota have the smallest number of earthquakes in the United States.

• The deepest earthquakes typically occur at plate boundaries where the Earth”s crust is being subducted into the Earth’s mantle. These occur as deep as 750 km (400 miles) below the surface.

• Alaska is the most earthquake-prone state and one of the most seismically active regions in the world. Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years.

• The majority of the earthquakes and volcanic eruptions occur along plate boundaries such as the boundary between the Pacific Plate and the North American plate. One of the most active plate boundaries where earthquakes and eruptions are frequent, for example, is around the massive Pacific Plate commonly referred to as the Pacific Ring of Fire.

• The earliest recorded evidence of an earthquake has been traced back to 1831 BC in the Shandong province of China, but there is a fairly complete record starting in 780 BC during the Zhou Dynasty in China.

• It was recognized as early as 350 BC by the Greek scientist Aristotle that soft ground shakes more than hard rock in an earthquake.

• The cause of earthquakes was stated correctly in 1760 by British engineer John Michell, one of the first fathers of seismology, in a memoir where he wrote that earthquakes and the waves of energy that they make are caused by “shifting masses of rock miles below the surface”.

• Subduction is the process of the oceanic lithosphere colliding with and descending beneath the continental lithosphere.

• In 1663 the European settlers experienced their first earthquake in America.

• Human beings can detect sounds in the frequency range 20-20,000 Hertz. If a P wave refracts out of the rock surface into the air, and it has a frequency in the audible range, it will be heard as a rumble. Most earthquake waves have a frequency of less than 20 Hz, so the waves themselves are usually not heard. Most of the rumbling noise heard during an earthquake is from buildings and their contents moving.

• When the Chilean earthquake occurred in 1960, seismographs recorded seismic waves that traveled all around the Earth. These seismic waves shook the entire earth for many days! This phenomenon is called the free oscillation of the Earth.

• The interior of Antarctica has icequakes which, although they are much smaller, are perhaps more frequent than earthquakes in Antarctica. The icequakes are similar to earthquakes, but occur within the ice sheet itself instead of the land underneath the ice. Some of our polar observers have told us they can hear the icequakes and see them on the South Pole seismograph station, but they are much too small to be seen on enough stations to obtain a location.

• On January 26, 1700 at about 9 PM Pacific time, the largest known earthquake in the continental U.S. occurred. We know the time so precisely because Japan has been recording tsunamis at least as far back as 684 CE, and this large Cascadia earthquake caused a tsunami that Japan recorded. We can work backwards from the time the tsunami arrived in Japan to determine when the earthquake happened.

• The present-day location of The Pinnacles is 195 mi (314 km) northwest from the volcano that the San Andreas sliced it from. We know these volcanic rocks are 23 million years old. That means the San Andreas fault has moved 0.59 in/yr (1.5 cm/yr) over the last 23 million years.

There's a 100 percent chance of an earthquake today.

There's a 100 percent chance of an earthquake today. Though millions of persons may never experience an earthquake, they are very common occurrences on this planet. So today -- somewhere -- an earthquake will occur.

It may be so light that only sensitive instruments will perceive its motion; it may shake houses, rattle windows, and displace small objects; or it may be sufficiently strong to cause property damage, death, and injury. It is estimated that about 700 shocks each year have this capability when centered in a populated area. But fortunately, most of these potentially destructive earthquakes center in unpopulated areas far from civilization.

Since a major portion of the world's earthquakes each year center around the rim of the Pacific Ocean (Ring of Fire), referred to by seismologists as the circum-Pacific belt, this is the most probable location for today's earthquake. But it could hit any location, because no region is entirely free of earthquakes.

Stating that an earthquake is going to occur today is not really "predicting earthquakes". To date, they cannot be predicted. But anyone, on any day, could make this statement and it would be true. This is because several million earthquakes occur annually; thereby, thousands occur each day, although most are too small to be located. The problem, however, is in pinpointing the area where a strong shock will center and when it will occur.

Earthquake prediction may some day become a reality, but only after much more is learned about earthquakes.

FACT: Earthquakes are sudden rolling or shaking events caused by movement under the Earth’s surface.

An earthquake is the ground shaking caused by a sudden slip on a fault. Stresses in the earth's outer layer push the sides of the fault together. Stress builds up and the rocks slip suddenly, releasing energy in waves that travel through the earth's crust and cause the shaking that we feel during an earthquake.

Faults are caused by the tectonic plates grinding and scraping against each other as they continuously and slowly move. In California, for example, there are two plates - the Pacific Plate (which extends from western California to Japan, including much of the Pacific Ocean floor) and the North American Plate (which is most of the North American continent and parts of the Atlantic Ocean). The Pacific Plate moves northwestward past the North American Plate along the San Andreas Fault at a rate of about two inches per year.

Parts of the San Andreas Fault system adapt to this movement by constant "creep" resulting in many tiny shocks and a few moderate earth tremors. In other parts, strain can build up for hundreds of years, producing great earthquakes when it finally releases. Large and small earthquakes can also occur on faults not previously recognized; recent earthquakes in Alabama and Virginia are good examples.

FICTION: “Mega Quakes” can really happen.

The magnitude of an earthquake is related to the area of the fault on which it occurs - the larger the fault area, the larger the earthquake. The San Andreas Fault is 800 miles long and only about 10-12 miles deep, so that earthquakes larger than magnitude 8.3 are extremely unlikely.

The largest earthquake ever recorded by seismic instruments anywhere on the earth was a magnitude 9.5 earthquake in Chile on May 22, 1960. That earthquake occurred on a fault that is almost 1,000 miles long and 150 miles wide, dipping into the earth at a shallow angle. The magnitude scale is open-ended, meaning that scientists have not put a limit on how large an earthquake could be, but there is a limit just from the size of the earth. A magnitude 12 earthquake would require a fault larger than the earth itself.

FICTION: Earthquakes only occur on the West Coast in the United States.

Earthquakes can occur in any location at any time. But history shows they occur in the same general patterns over time, principally in three large zones of the earth. The world's greatest earthquake zone, the circum-Pacific seismic belt, is found along the rim of the Pacific Ocean, where about 81 percent of the world's largest earthquakes occur. That belt extends from Chile, northward along the South American coast through Central America, Mexico, the West Coast of the United States, the southern part of Alaska, through the Aleutian Islands to Japan, the Philippine Islands, New Guinea, the island groups of the Southwest Pacific, and to New Zealand.

The second important belt, the Alpide, extends from Java to Sumatra through the Himalayas, the Mediterranean, and out into the Atlantic. This belt accounts for about 17 percent of the world's largest earthquakes, including some of the most destructive.

The third prominent belt follows the submerged mid-Atlantic ridge. The remaining shocks are scattered in various areas of the world. Earthquakes in these prominent seismic zones are taken for granted, but damaging shocks occur occasionally outside these areas. Examples in the United States are New Madrid, Missouri, and Charleston, South Carolina. Many decades to centuries, however, usually elapse between such destructive shocks.

FICTION: The 1906 San Francisco earthquake was the deadliest ever.

Though well known, the magnitude 7.8 San Francisco earthquake and ensuing fire killed 3,000 and razed large sections of the city. It was the most deadly in U.S. history, but that doesn’t make it the worst the world has seen, by far. The deadliest earthquake in recorded history struck Shensi province in China in 1556, killing about 830,000 people. The 1976 magnitude 7.8 earthquake which struck Tangshan, China killed somewhere between 250,000 and 800,000 people. In 2003, the magnitude 6.5 earthquake in Bam, Iran killed more than 40,000 people.

The earthquake in Chile on May 22, 1960, is the strongest to be recorded in the world with magnitude 9.5, and killed more than 4,000. For the record, the largest U.S. earthquake occurred on March 28, 1964, in Alaska. It was a magnitude 9.2 quake and took 131 lives.

PARTIALLY FACT: California has the most earthquakes in the United States.

Alaska registers the most earthquakes in a given year, with California placing second, until 2014 when a sudden increase in seismicity in Oklahoma pushed it well past California as the second most active in terms of magnitude (M) 3.0 and greater earthquakes. In 2014 there were 585 M3 and greater earthquakes in Oklahoma and about 200 in California. As of April 2015 Oklahoma (260 events) is still well ahead of California (29 events).

California, however, has the most damaging earthquakes, including a M6.0 earthquake near Napa in August 2014, because of its greater population and extensive infrastructure. Most of Alaska’s large earthquakes occur in remote locations such as along the Aleutian Island chain. Florida and North Dakota have the fewest earthquakes each year.

FACT: Earthquakes can occur near the surface or deep below the surface.

Earthquakes occur in the crust or upper mantle, from the earth’s surface to about 400 miles below the surface. But the very deepest earthquakes only occur at subduction zones where cold crustal rock is being pushed deep into the earth. In California, earthquakes are almost all in the top 15 miles of the crust, except in northern California along the Cascadia Subduction Zone, which extends into Oregon, Washington, and British Columbia.

Seismologists use earthquakes to study the interior of the earth and to pinpoint faults and geologic structures such as the core-mantle boundary, subduction zones, and the subsurface extent of the San Andreas Fault. Using earthquakes and waves from earthquakes, scientist can see all of the earth’s interior.

FICTION: The ground can open up during an earthquake.

A popular cinematic and literary device is a fault that opens during an earthquake to swallow up an inconvenient character. But unfortunately for principled writers, gaping faults exist only in movies and novels. The ground on the two sides of the fault slide past each other, they do not pull apart. If the fault could open, there would be no friction. Without friction, there would be no earthquake. Shallow crevasses can form during earthquake induced landslides, lateral spreads, or other types of ground failures. Faults, however, do not gape open during an earthquake.

FICTION: California will eventually fall into the ocean.

The ocean is not a great hole into which California can fall, but it is itself land at a somewhat lower elevation with water above it. It’s absolutely impossible that California will be swept out to sea. Instead, southwestern California is moving horizontally northward towards Alaska as it slides past central and eastern California. The dividing point is the San Andreas fault system, which extends from the Salton Sea in the south to Cape Mendocino in the north. This 800 mile long fault is the boundary between the Pacific Plate and North American Plate. The Pacific Plate is moving to the northwest with respect to the North American Plate at approximately 46 millimeters (two inches) per year (the rate your fingernails grow). At this rate, Los Angeles and San Francisco will one day (about 15 million years from now) be next-door neighbors, and in an additional 70 million years, Los Angeles residents will find themselves with an Alaska zip code!

FICTION: An earthquake on the San Andreas fault can cause a large tsunami.

The San Andreas fault cannot create a big tsunami like the ones that happened in Sumatra in 2004 or Japan in 2011. Those earthquakes happened on subduction zone faults, on which fault slip caused vertical uplift of the sea floor. While a part of the San Andreas fault near and north of San Francisco is offshore, the motion is mostly horizontal, so it will not cause large vertical motions of the ocean floor that would generate a tsunami. Earthquakes on other faults offshore California as well as underwater landslides triggered by strong shaking can create local tsunamis, some of which may be locally damaging.

PARTIALLY FACT: An “Aftershock” can be greater than the initial earthquake.

“Foreshock”, “mainshock”, and “aftershock” are relative terms, all of which describe earthquakes. Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a larger event or “mainshock”. They mostly occur within 1-2 fault lengths of the mainshock. For the largest earthquakes, this is a long distance; it is thought that the 1906 San Francisco earthquake triggered events in southern California, western Nevada, southern central Oregon, and western Arizona, all within 2 days of the mainshock.

As a general rule, aftershocks represent readjustments in the vicinity of a fault that slipped at the time of the mainshock. The frequency of these aftershocks decreases with time. If an aftershock is larger than the first earthquake then we call it the mainshock and the previous earthquakes in a sequence become foreshocks. About 5% to 10% of earthquakes in California are followed by a larger one within a week and then are considered a foreshock.

It is possible to have two earthquakes of about the same size in a sequence. There is a 5% chance of having the two largest earthquakes in a sequence be within 0.2 units of magnitude, during the first week of a sequence. Given that very large earthquakes are rare to begin with, it is not surprising that we have not yet observed two very large earthquakes so close together in time in California.

NOT LIKELY: Two major earthquakes occurred on the same day, so they must be related.

Often, people wonder if an earthquake in Alaska may have triggered an earthquake in California; or if an earthquake in Chile is related to an earthquake that occurred a week later in Mexico. Over long distances, the answer is no. Even the Earth's rocky crust is not rigid enough to transfer stress efficiently over thousands of miles. There is evidence to suggest that earthquakes in one area can trigger seismic activity within a few hundred miles, including aftershocks clustered near the main shock. There is also evidence that some major earthquakes manage to trigger seismicity over much greater distances (thousands of miles), but these triggered quakes are small and very short lived.

PARTIALLY FACT: People can cause earthquakes.

Earthquakes induced by human activity have been documented in the United States, Japan, and Canada. The cause was injection of fluids into deep wells for waste disposal and secondary recovery of oil, and the filling of large reservoirs for water supplies. Most of these earthquakes were minor. Deep mining can cause small to moderate quakes and nuclear testing has caused small earthquakes in the immediate area surrounding the test site, but other human activities have not been shown to trigger subsequent earthquakes.

Within the central and eastern United States, the number of earthquakes has increased dramatically over the past few years. Between the years 1973-2008, there was an average of 21 earthquakes of magnitude three and larger in the central and eastern United States. This rate jumped to an average of 99 M3+ earthquakes per year in 2009?2013, and the rate continues to rise. In 2014, alone, there were 659 M3 and larger earthquakes . Most of these earthquakes are in the magnitude 3?4 range, large enough to have been felt by many people, yet small enough to rarely cause damage. There were reports of damage from some of the larger events, including the M5.6 Prague, Oklahoma earthquake and the M5.3 Trinidad, Colorado earthquake.

The increase in seismicity has been found to coincide with the injection of wastewater in deep disposal wells in several locations, including Colorado, Texas, Arkansas, Oklahoma and Ohio. Much of this wastewater is a byproduct of oil and gas production and is routinely disposed of by injection into wells specifically designed and approved for this purpose. Hydraulic fracturing, commonly known as “fracking”, does not appear to be linked to the increased rate of magnitude 3 and larger earthquakes.

See also: USGS Induced Earthquakes Research

FICTION: People can stop earthquakes.

We cannot prevent earthquakes from happening (or stop them once they’ve started). However, we can significantly mitigate their effects by characterizing the hazard (e.g., identifying earthquake faults, unconsolidated sediment likely to amplify earthquake waves, and unstable land prone to sliding or liquefying during strong shaking), building safer structures, and preparing in advance by taking preventative measures and knowing how to respond.

There are many things being done now by the USGS and other agencies to protect people and property in the United States in the event of a major earthquake. These include Earthquake Early Warning, Earthquake Rupture Forecasts and Probabilistic Seismic Hazard Assessments.

FICTION: Nuclear explosions can start or stop earthquakes.

Scientists agree that even large nuclear explosions have little effect on seismicity outside the area of the blast itself. The largest underground thermonuclear tests conducted by the United States were detonated in Amchitka at the western end of the Aleutian Islands, and the largest of these was the 5 megaton test code-named Cannikin that occurred on November 6, 1971 that did not trigger any earthquakes in the seismically active Aleutian Islands.

On January 19, 1968, a thermonuclear test, code-named Faultless, took place in central Nevada. The code-name turned out to be a poor choice because a fresh fault rupture some 4,000 feet long was produced. Seismograph records showed that the seismic waves produced by the fault movement were much less energetic than those produced directly by the nuclear explosion. Locally, there were some minor earthquakes surrounding the blasts that released small amounts of energy. Scientists looked at the rate of earthquake occurrence in northern California, not far from the test site, at the times of the tests and found nothing to connect the testing with earthquakes in the area.

FICTION: You can prevent large earthquakes by making lots of small ones, or by “lubricating” the fault with water.

Seismologists have observed that for every magnitude 6 earthquake there are about 10 of magnitude 5, 100 of magnitude 4, 1,000 of magnitude 3, and so forth as the events get smaller and smaller. This sounds like a lot of small earthquakes, but there are never enough small ones to eliminate the occasional large event. It would take 32 magnitude 5's, 1000 magnitude 4's, OR 32,000 magnitude 3's to equal the energy of one magnitude 6 event. So, even though we always record many more small events than large ones, there are far too few to eliminate the need for the occasional large earthquake.

As for “lubricating” faults with water or some other substance, if anything, this would have the opposite effect. Injecting high-pressure fluids deep into the ground is known to be able to trigger earthquakes—to cause them to occur sooner than would have been the case without the injection. This would be a dangerous pursuit in any populated area, as one might trigger a damaging earthquake.

FICTION: We can predict earthquakes.

There is no scientifically plausible way of predicting the occurrence of a particular earthquake. The USGS can and does make statements about earthquake rates, describing the places most likely to produce earthquakes in the long term. It is important to note that prediction, as people expect it, requires predicting the magnitude, timing, and location of the future earthquake, which is not currently possible. The USGS and other science organizations are working to better understand earthquakes in the hope of eventually being able to predict the size, location and time that an earthquake will happen. The USGS does produce aftershock forecasts that give the probability and expected number of aftershocks in the region following large earthquakes.

FICTION: Animals can predict earthquakes.

Changes in animal behavior cannot be used to predict earthquakes. Even though there have been documented cases of unusual animal behavior prior to earthquakes, a reproducible connection between a specific behavior and the occurrence of an earthquake has not been made. Because of their finely tuned senses, animals can often feel the earthquake at its earliest stages before the humans around it can. This feeds the myth that the animal knew the earthquake was coming. But animals also change their behavior for many reasons, and given that an earthquake can shake millions of people, it is likely that a few of their pets will, by chance, be acting strangely before an earthquake.

MAYBE: Some people can sense that an earthquake is about to happen.

There is no scientific explanation for the symptoms some people claim to have preceding an earthquake, and more often than not there is no earthquake following the symptoms.

FICTION: It’s been raining a lot, or very hot--it must be earthquake weather!

Many people believe that earthquakes are more common in certain kinds of weather. In fact, no correlation with weather has been found. Earthquakes begin many kilometers (miles) below the region affected by surface weather. People tend to notice earthquakes that fit the pattern and forget the ones that don't. Also, every region of the world has a story about earthquake weather, but the type of weather is whatever they had for their most memorable earthquake.

NOT LIKELY: The Golden Gate Bridge, Seattle Space Needle and other buildings will all eventually fall during an earthquake.

Damage in earthquakes depends on the strength of the ground shaking and the ability of a structure to accommodate this shaking. Building codes define the guidelines for how strong structures need to be to perform well in earthquakes and continue to evolve as engineers and scientists better understand earthquakes and how structures respond to ground shaking.

Based on the type of construction and the building code at the time when they were built, we have a pretty good understanding of what buildings are likely to be damaged in future earthquakes. A detailed scientific assessment of the likely damage in a big San Andreas earthquake in southern California (The ShakeOut Earthquake Scenario - A Story That Southern Californians Are Writing) estimated that 300,000 buildings in southern California would be damaged at a moderate level (losing at least 10% the value of the building) as modeled in the M7.8 ShakeOut scenario earthquake. Although this is a large number, it is only 1 out of every 16 buildings in the region. Most buildings will not have significant damage. Moreover, only 1,500 of those buildings will actually collapse. That is less than 1 out of 30,000 buildings in southern California. Widespread collapse of many buildings is not realistic.

FACT: Earthquakes don’t kill people, buildings and their contents do.

The greatest risk in an earthquake is the severity of the shaking it causes to manmade and natural structures and the contents within these that may fail or fall and injure or kill people. There have been large earthquakes with very little damage because they caused little shaking and/or buildings were built to withstand that shaking. In other cases, smaller earthquakes have caused great shaking and/or buildings collapsed that were never designed or built to survive shaking.

Much depends on two variables: geology and engineering. From place to place, there are great differences in the geology at and below the ground surface. Different kinds of geology will do different things in earthquakes. For example, shaking at a site with soft sediments can last 3 times as long as shaking at a stable bedrock site such as one composed of granite.

Local soil conditions also play a role, as certain soils greatly amplify the shaking in an earthquake. Seismic waves travel at different speeds in different types of rocks. Passing from rock to soil, the waves slow down but get bigger. A soft, loose soil will shake more intensely than hard rock at the same distance from the same earthquake. The looser and thicker the soil is, the greater the energy movement will be. Fires are another major risk during earthquakes as gas lines may be damaged and particularly hazardous.

FICTION: During an earthquake you should head for the doorway.

That’s outdated advice. In past earthquakes in unreinforced masonry structures and adobe homes, the door frame may have been the only thing left standing in the aftermath of an earthquake. Hence, it was thought that safety could be found by standing in doorways. In modern homes doorways are no stronger than any other parts of the house and usually have doors that will swing and can injure you.

YOU ARE SAFER PRACTICING THE “DROP, COVER, AND HOLD ON” maneuver under a sturdy piece of furniture like a strong desk or table. If indoors, stay there. Drop to the floor, make yourself small and get under a desk or table or stand in a corner. If outdoors, get into an open area away from trees, buildings, walls and power lines. If in a high-rise building, stay away from windows and outside walls, stay out of elevators, and get under a table. If driving, pull over to the side of the road and stop. Avoid overpasses and power lines. Stay inside your car until the shaking is over. If in a crowded public place, do not rush for the doors. Crouch and cover your head and neck with your hands and arms. You should practice the “DROP, COVER AND HOLD ON” method at work and at home at least twice a year.

FICTION: Everyone will panic during the Big One.

A common belief is that people always panic and run around madly during and after earthquakes, creating more danger for themselves and others. Actually, research shows that people usually take protective actions and help others both during and after the shaking. Most people don't get too shaken up about being shaken up!

FICTION: You can’t plan ahead for an earthquake.

There are plenty of things you can do right now to prepare if you live in an earthquake-prone area.

1. Make sure each member of your family knows what to do no matter where they are when earthquakes occur:
   • Establish a meeting place where you can all reunite afterward.
   • Find out about earthquake plans developed by children's school or day care.
   • Remember transportation may be disrupted, so keep some emergency supplies--food, liquids, and comfortable shoes, for example--at work.
2. KNOW where your gas, electric and water main shutoffs are and how to turn them off if there is a leak or electrical short. Make sure older members of the family can shut off utilities.
3. LOCATE your nearest fire and police stations and emergency medical facility.
4. TALK to your neighbors--how could they help you, or you them after an earthquake?
5. TAKE Red Cross First Aid and CPR Training Course.
6. MAKE your disaster supply kit. Beyond the usual flashlights, batteries and radios, include a first-aid kit; work gloves; sturdy shoes or boots; a week’s supply of any presciption medications you or your family might need; credit card and cash; personal identifcation; extra set of keys; matches in a waterproof container; map of your area; phone numbers of family and other important people (doctors, veterinarians, etc.); copies of insurance policies and other important documents; special needs equipment (diapers, baby formula, hearing aid batteries; spare eyeglasses, etc.); three gallons of water per person; three-day supply of food per person; hand tools; a portable ABC fire extinguisher; sanitation supplies for you and your family; entertainment (toys, books, coloring books and crayons, playing cards)
7. BOLT bookcases, china cabinets, tall furniture, file cabinets, etc. to wall studs. Brace or anchor heavy electronics and other heavy items. Secure items that might fall. Move heavy or fragile items to lower shelves. Fasten drawers and cabinet doors with latches or locks. Brace overhead light fixtures. Strap your water heater to wall studs and bolt down any gas appliances. Look for other non-structural steps you can take in your home and workplace to reduce your chances for injury and loss.
8. ASK AN ENGINEER about the seismic safety of your home and/or business. It’s well known that unreinforced masonry structures can fail quickly during earthquakes. An inspection by a structural engineer now can help you decide if retrofitting will help your property withstand shaking.

FACT: The U.S. Geological Survey is conducting research to better forecast the effects of potentially damaging earthquakes throughout the United States and mitigate their effects.

Basic and applied scientific research is being carried out to predict the types of ground shaking expected from future large earthquakes based upon the probabilities (or likelihoods) of those earthquakes occurring, the physics of the earthquake source, the propagation of seismic waves through the Earth’s crust and local site effects. Together with rupture scenarios for specific faults, these hazard assessments are essential for multiple applications, including:

• Probabilistic seismic hazard assessments such as the National Seismic Hazard Map that underlie seismic provisions of building and other regulatory codes; as well as detailed urban seismic hazard maps that include the effects of rupture directivity, 3D basin response and soil nonlinearity. These urban hazard maps will be included in code updates for selected regions.
• Development of credible earthquake scenarios for specific faults with synthetic ground-motion time histories for evaluating current engineering design practice, improving building codes and for emergency planning and public education.
• Other uses of these hazard products include: 1) site-specific designs and retrofits of critical and major facilities such as bridges, hospitals, nuclear power reactors, dams and tall buildings, 2) modeling damage patterns and damage to specific structures after earthquakes, 3) assessing secondary earthquake hazards such as liquefaction and landslides and 4) computing actuarially sound earthquake insurance premiums.

If people were asked where in the United States do most earthquakes happen, they are likely to answer California. They’d be correct. But earthquakes are a hazard in other parts of the country, too.

The U.S. Geological Survey (USGS) estimates that nearly half of all Americans live in areas with some potential for damaging earthquakes. That includes people living in the central states where there is what USGS calls “strong shaking potential.”

If you live under the threat of earthquakes, there are ways you can prepare. They start with collecting emergency supplies, including personal needs, and planning ahead. Here are three more ways you can prepare.

There’s no way to know when or where an earthquake will happen. The best scientists can do is calculate the probability that a significant earthquake will happen in a specific area within a certain number of years.

It is, however, possible to better know the earthquake hazard where you live and the earthquake risk to your community.

An earthquake hazard is anything associated with an earthquake that may affect the normal activities of people. This includes landslide, liquefaction, tsunamis, and seiches.

Use the USGS National Seismic Hazard Map to learn the general earthquake hazard in your area. The map shows how many times earthquakes could cause damaging ground shaking in 10,000 years. That doesn’t mean the earthquakes won’t happen before. They could happen at any time.

Your earthquake risk is the probable building damage and the number of people that are expected to be hurt or killed if an earthquake occurs on a particular fault. Earthquake risk and earthquake hazard are sometimes incorrectly used interchangeably. High earthquake hazard does not mean high risk.

The best way for you to stay informed about both the hazard and risk to your community is to contact your local emergency management or geological survey office. Understanding your risk can help you take steps to protect yourself and your property.

Earthquakes can trigger tsunamis. A tsunami can strike any U.S. coast, but the hazard is greatest in places near subduction zones. For example, Hawaii, Alaska, Washington, Oregon, California, and the U.S. Caribbean islands. If you live along the coast in one of these places, you are at risk from tsunamis.

Earthquakes can have immediate and long-term impacts on health and safety. They can cause injuries, anxiety and stress, and death.

Participating in emergency response activities like the Great ShakeOut earthquake drill can teach you practical skills that you can use during an earthquake. Take these steps:

1. STOP and stay put. Stay inside if you are inside and outside if you are outside. If inside and if possible, move away from glass, hanging objects, bookcases, cabinets, and large furniture that could fall. If you are outside, move away from buildings, utility wires, and fuel and gas lines.
2. DROP down onto your hands and knees. This position protects you from falling but allows you to still move if necessary.
3. COVER your head and neck (and your entire body if possible) underneath a table or desk. If there is no shelter nearby, get down near an interior wall or next to low-lying furniture that won’t fall on you, and cover your head and neck with your arms and hands. If you are in bed, hold on and stay there. Protect your head with a pillow.
4. HOLD ON to your shelter (or to your head and neck) until the shaking stops. Be prepared to move with your shelter if the shaking shifts it around.

Studies of injuries and deaths caused by earthquakes over several decades show that you are much more likely to be injured by falling or flying objects than to die in a collapsed building.

Imagine your home or workplace being picked up and shaken sideways. What would be thrown around and cause injury or damage?

Reduce your risk of injury by taking no-cost steps to secure the space around you:

• Move or secure furniture, such as bookcases, away from beds, sofas, or other places where people sit, sleep, or spend a lot of time.
• Move heavy objects to lower shelves.
• Move heavy or unstable objects away from doors and escape routes.

Consider buying earthquake insurance if you have the means and live someplace where there’s a high earthquake hazard. Standard homeowners’ and renters’ insurance policies do not cover damage resulting from land movement or landslides.

Earthquake insurance isn’t a realistic option for everyone. Increases in insurance premiums have made it difficult to find coverage in many areas. California experiences 90% of the country’s earthquakes, but only 10% of residents had earthquake insurance in 2014.

There are many things to consider when deciding whether to buy earthquake insurance. They include how often earthquakes happen in your area, how long it’s been since the last earthquake, the value of your home and its contents, and the cost of the insurance and restrictions on coverage (i.e., the deductible).

There are many places in the United States, called “fault zones,” that are at risk for serious earthquakes. These include states along the west coast, in the south, and in the central United States. While very strong or intense earthquakes are rare, less powerful earthquakes can also be dangerous. The key to surviving an earthquake and reducing your risk of injury lies in planning, preparing, and practicing what you and your loved ones will do if it happens.

Know the signs of an earthquake.

During an earthquake, you may hear a roaring or rumbling sound that gradually gets louder. You may also feel a rolling sensation that starts out gently and, within a second or two, grows violent.

OR

You may first be jarred by a violent jolt. A second or two later, you may feel shaking and find it difficult to stand up or move from one room to another.

Learn the safe spots.

During an earthquake, most deaths and injuries are caused by collapsing building materials and heavy falling objects, such as bookcases, cabinets, and heating units.

• Learn the safe spots in each room of your home. A safe spot may be underneath a sturdy table away from walls or underneath your covers with a pillow over your head if you are already in bed.

Plan and practice what to do if an earthquake strikes.

By planning and practicing what to do if an earthquake strikes, you and your loved ones can learn to react correctly and automatically when the shaking begins.

• Get the entire family to practice an earthquake drill, especially if you have children. Participating in an earthquake drill will help you and your loved ones understand what to do in case you are not with them during an earthquake.
• Make sure you and your children also understand the school’s emergency procedures for disasters. This will help you coordinate where, when, and how to reunite with your children after an earthquake.

Drop, cover, and hold on during your earthquake drill.

• DROP down onto your hands and knees immediately. This position protects you from falling but still allows you to move if necessary.
• COVER your head and neck (and your entire body if possible) underneath a sturdy table or desk. If there is no shelter nearby, get down near an interior wall or next to low-lying furniture that won’t fall on you, and cover your head and neck with your arms and hands. Try to stay clear of windows or glass that could shatter or objects that could fall on you.
• HOLD ON to your shelter (or to your head and neck) until the shaking stops. Be prepared to move with your shelter if the shaking shifts it around.

Create an evacuation plan.

If an earthquake happens, you and your loved ones may need to evacuate a damaged area afterward. By planning and practicing for evacuation, you will be better prepared to respond appropriately and efficiently to signs of danger or to directions by civil authorities.

• Take a few minutes with your family to discuss a home evacuation plan. Sketch a floor plan of your home, walk through each room, and discuss evacuation details. If you live downstream from a dam, know flood-zone information.
• Plan a second way to exit from each room or area, if possible. If you need special equipment, such as a rope ladder, mark where it is located.
• Mark where your emergency supply kit (including food, water, first aid) and fire extinguishers are located.
• Locate where the utility switches or valves are located so that they can be turned off, if possible.
• Indicate the location of your family’s emergency outdoor meeting place.

Create an emergency supply kit.

Stock up on emergency supplies that can be used after an earthquake. These supplies should include a first aid kit and emergency supply kits for the home and automobileexternal icon, including emergency water and food. Store enough supplies to last at least 3 days.

You should also make a list of important information (like telephone numbers of emergency contacts, insurance information, and important medical information) and gather any important documents (like medical documents, birth certificates, and passports). Store these items in a secure location like a fireproof or waterproof safe.

Items for your home

Assemble an emergency supply kit for your home. In addition to your standard emergency supply kit, some additional items that may help after an earthquake include the following:

• An ax
• A shovel
• A broom
• A rope for towing or rescue
• Sturdy shoes that can provide protection from broken glass, nails, and other debris
• Gloves (heavy and durable for cleaning up debris)
• Fire extinguisher (multipurpose, dry chemical type)
• A whistle or other signaling device carried in your purse or backpack

Prepare your home for earthquakes

Secure hazards in your home.

Make sure to inspect your home and its surrounding for any possible hazards and secure them if you can. Remember: anything can move, fall, or break during an earthquake or its aftershocks.

• Identify potential hazards in each room, including windows and other glass items, unanchored bookcases, furniture that can topple, items on shelves, and areas that could be blocked by falling debris. Secure them, where possible, with “L” brackets, corner brackets, aluminum molding, or eyebolts.
• Secure cabinet doors by installing sliding bolts or childproof latches.
• Secure your large appliances (like refrigerators, water heaters, and stoves) with flexible cable, braided wire, or metal strapping. Wrap your water heater and attach it to wall studs.
• Move heavy mirrors and pictures hanging above beds, chairs, and other places where you sit or sleep. Otherwise, anchor these items with wire through eye screws bolted into wall studs. Or place screws on both sides, top, and bottom of the frame and screw these into the studs.
• Replace heavy ceramic or glass hanging planters with light-weight plastic or wicker baskets.
• Identify poisons, solvents, or toxic materials in breakable containers and move these containers to a safe, well-ventilated storage area. Keep them away from your water storage and out of reach of children and pets.

Tips for Securing Shelves

To keep items from falling off open shelves, attach a wooden or metal guardrail to each shelf. You can also use fishing line for a less visible alternative.

You should also make sure to place heavy or large objects on lower shelves. Use Velcro®-type fastenings to secure some items to their shelves.

Inspect and secure your home’s structure.

Examine the structural safety of your house. If your house is of conventional wood construction, it will probably be relatively resistant to earthquake damage, particularly if it is a single-story structure.

• Strengthen the areas of connection between beams, posts, joists, and plates using “T” and “L” straps, mending plates, joist hangers, twin post caps, and nails and lap screws. Pay particular attention to exposed framing in garages, basements, porches, and patio covers.
• Check your chimney or roof for loose tiles and bricks that could fall in an earthquake. Repair loose tiles or bricks, as needed.
• Protect yourself from falling chimney bricks that might penetrate the roof, by reinforcing the ceiling immediately surrounding the chimney with 3/4-inch plywood nailed to ceiling joists.

For information on structural safety standards and qualified contractors in your area, contact your city or county government office on community development or building code enforcement. If you want to do the work yourself, many hardware or home-improvement stores will assist you with information and instructions.

Shut off utilities.

• Know where and how to shut off utilities, including gas, electricity, and water, at the main switches or valves. Check with your local utility companies for instructions.
• Teach all family members how and when to shut off utilities.

1. Fire extinguisher

2. Adequate supplies of medications that you or family members are taking

3. Crescent and pipe wrenches to turn off gas and water supplies

4. First-aid kit and handbook

5. Flashlights with extra bulbs and batteries

6. Portable radio with extra batteries

7. Water for each family member for at least two weeks (allow at least 1 gallon per person per day) and purification tablets or chlorine bleach to purify drinking water from other sources

8. Canned and package foods, enough for several days and mechanical can opener. Extra food for pets if necessary

9. Camp stove or barbecue to cook on outdoors (store fuel out of the reach of children)

10. Waterproof, heavy-duty plastic bags for waste disposal.

Know what to do to keep yourself and your loved ones safe during an earthquake. In most situations, you can protect yourself if you immediately DROP, COVER, and HOLD ON.

Drop. Cover. Hold on.

In most situations, you can protect yourself if you immediately:

• DROPdown onto your hands and knees before the earthquake knocks you down. This position protects you from falling but allows you to still move if necessary.
• COVERyour head and neck (and your entire body if possible) underneath a sturdy table or desk. If there is no shelter nearby, get down near an interior wall or next to low-lying furniture that won’t fall on you, and cover your head and neck with your arms and hands.
• HOLD ON to your shelter (or to your head and neck) until the shaking stops. Be prepared to move with your shelter if the shaking shifts it around.

If you are inside, stay inside.

DO NOT run outside or to other rooms during an earthquake. You are less likely to be injured if you stay where you are.

To reduce your chances of being hurt, take the following actions:

• If possible, within the few seconds before shaking intensifies, quickly move away from glass, hanging objects, bookcases, china cabinets, or other large furniture that could fall. Watch for falling objects, such as bricks from fireplaces and chimneys, light fixtures, wall hangings, high shelves, and cabinets with doors that could swing open.
• If available nearby, grab something to shield your head and face from falling debris and broken glass.
• If you are in the kitchen, quickly turn off the stove and take cover at the first sign of shaking.
• If you are in bed, hold on and stay there, protecting your head with a pillow. You are less likely to be injured staying where you are. Broken glass on the floor can cause injuries if you walk or roll onto the floor.

DO NOT stand in a doorway.You are safer under a table. In modern houses, doorways are no stronger than any other part of the house. Doorways do not protect you from the most likely source of injury − falling or flying objects. Most earthquake-related injuries and deaths are caused by falling or flying objects (such as TVs, lamps, glass, or bookcases), or by being knocked to the ground.

If you are in a high-rise building, drop, cover, and hold on.

• Move away from windows and outside walls.
• Stay in the building.
• DO NOT use the elevators. The electricity may go out, and the sprinkler systems may come on.
• If you are trapped, stay calm. Try to get someone’s attention by tapping on hard or metal parts of the structure. Doing so may increase your chances of being rescued.

If you are inside a crowded place, drop, cover, and hold on.

• Do not rush for the doorways. Others will have the same idea.
• Move away from display shelves containing objects that may fall.
• If you can, take cover and grab something to shield your head and face from falling debris and glass.

If you are outside, stay outside.

Stay inside if you are inside and outside if you are outside.

• Move away from buildings, utility wires, sinkholes, and fuel and gas lines. The greatest danger from falling debris is just outside doorways and close to outer walls of buildings.
• Go to an open area away from trees, telephone poles, and buildings. Once in the open, get down low and stay there until the shaking stops.
• The area near the outside walls of a building is the most dangerous place to be. Windows, facades, and architectural details are often the first parts of the building to collapse. Stay away from this danger zone.

If you are in a moving vehicle, stop as quickly and safely as possible.

• Move your car to the shoulder or curb, away from utility poles, overhead wires, and under- or overpasses.
• Stay in the car and set the parking brake. A car may jiggle violently on its springs, but it is a good place to stay until the shaking stops.
• Turn on the radio for emergency broadcast information.
• If a power line falls on the car, stay inside until a trained person removes the wire.
• When it is safe to begin driving again, watch for hazards created by the earthquake, such as breaks in the pavement, downed utility poles and wires, rising water levels, fallen overpasses, or collapsed bridges.

If you are in a stadium or theater, stay in your seat. Protect your head and neck with your arms or any way possible.

• Do not leave until the shaking is over.
• Walk out carefully watching for anything that could fall during the aftershocks.

If you are near the shore, drop, cover, and hold on until the shaking stops.

• If severe shaking lasts 20 seconds or more, immediately evacuate to high ground as a tsunami might have been generated by the earthquake.
• Move inland 2 miles (3 kilometers) or to land that is at least 100 feet (30 meters) above sea level immediately. Don’t wait for officials to issue a warning.
• Walk quickly, rather than drive, to avoid traffic, debris, and other hazards.

If you cannot drop to the ground, try to sit or remain seated so you are not knocked down.

• If you are in a wheelchair, lock your wheels. Remove any items that are not securely attached to the wheelchair.
• Protect your head and neck with a large book, a pillow, or your arms. The goal is to prevent injuries from falling down or from objects that might fall or be thrown at you.
• If you are able, seek shelter under a sturdy table or desk. Stay away from outer walls, windows, fireplaces, and hanging objects.
• If you are unable to move from a bed or chair, protect yourself from falling objects by covering up with blankets and pillows.
• If you are outside, go to an open area away from trees, telephone poles, and buildings, and stay there.
• For more resources for people with impaired mobility and other access and functional needs, visit the Earthquake Country Alliance.

Damaged buildings, damaged power lines, and leaking gas and water lines are just a few of the hazards you might face after an earthquake. Keep yourself and your loved ones safe after an earthquake by following the recommendations below.

Expect aftershocks.

• After an earthquake, you may experience aftershocks. Aftershocks are smaller earthquakes that follow a larger earthquake. These can happen minutes, days, weeks, or even months after an earthquake.
• If you feel an aftershock, DROP, COVER, and HOLD ON.

If you are trapped, attract attention to yourself.

• Try to attract attention to yourself. Send a text, bang on a wall or a pipe, or use a whistle to help rescuers find you.
• Protect your mouth, nose, and eyes from dust.

If you are in an area at risk for tsunamis, go inland and seek higher ground.

• In some cases, earthquakes can cause tsunamis in areas along the coast. These can happen minutes to hours after a strong earthquake.
• If you hear an official tsunami warning or notice signs of a tsunami, evacuate immediately. Get to higher ground as far inland as possible. Follow instructions from local authorities — they may direct you to a different route than you had planned.
• Visit the American Red Cross Tsunami Preparedness webpage for information on how to prepare for and stay safe during and after a tsunami.
• Learn about health and safety risks from tsunamis.

Be careful near damaged buildings.

• Do not enter a damaged building. Earthquakes can damage buildings and make them unsafe. Wait until local authorities tell you it is safe to go inside.
• Leave your home or building if you hear shifting or unusual noises. Strange noises could mean the building is about to fall.

Inspect your home for damage.

• Carefully check your home’s walls, floors, doors, windows, and staircases for damage. If you see structural damage, like cracks in the foundation or missing support beams, you may need to relocate to a shelter or another safe location.
• Check gas, electrical, and water lines for damage. If you smell gas or see a broken line, shut off the main valve from the outside. (Note: if gas is turned off, a professional must restore service.)
• Do not use matches, lighters, appliances, or light switches until you are sure there are no gas leaks. Sparks from electrical switches could ignite gas, causing an explosion.
• For more information, visit American Red Cross – Checking Your Home: Structural Elements.

If the power is out, use flashlights instead of candles.

• If you must use candles, keep them away from anything that can catch fire. Always stay near lit candles.
• Keep a fire extinguisher handy, and make sure your family knows how to use it. Read the National Fire Protection Association’s tips for using fire extinguishers.

• Learn more about hazards related to power outages.

Take care of any wounds or injuries to prevent infection.

• The risk for injury during and after an earthquake is high. Get first aid quickly to help heal small wounds and prevent infection.
• Learn more about proper wound care after a disaster.

If you can, help others in need.

• Check to make sure you are not hurt. If you are able, help others.
• Follow FEMA’s advice for how you can help others during an emergency.

Stay away from power lines.

• Watch out for fallen power lines that may be hanging overhead.
• Stay clear of fallen power lines. Call the electric company to report them.
• Learn more on how to protect yourself from electrical hazards after a disaster.

Prevent carbon monoxide poisoning.

Fuel-burning equipment creates carbon monoxide (CO). This can include equipment like generators, pressure washers, charcoal grills, and camp stoves. You can’t smell or see carbon monoxide, but if it builds up in your home, it can cause sudden illness and death.

• Never use portable gasoline or coal-burning equipment or camp stoves inside your home, basement, or garage. Keep it outside and at least 20 feet from any window, door, or vent.
• Use a battery-operated or battery backup CO detector any time you use a generator or anything else that burns fuel.
• If you have a CO detector and it starts beeping, leave your home right away and call 911.

Protect yourself from animals and pests.

• Stay away from wild or stray animals after an earthquake. Call 911 or your public health department to report them.
• Report dead animals to local officials.
• Learn more on how to protect yourself from animals or pests after a disaster.

Drink safe water. Eat safe food.

• Throw away perishable foods that have not been refrigerated properly due to power outages; also discard foods with an unusual odor, color, or texture. When in doubt, throw it out.
• Listen to reports from local officials for advice on water precautions in your home. Do not use contaminated water to make baby formula, make ice, brush your teeth, wash and prepare food, wash your hands, or wash dishes.
• Bottled, boiled, or treated water is safe for drinking, cooking, and personal hygiene. Your state, tribal, local, or territorial health department can make specific recommendations for boiling or treating water in your area.
• Learn more on how to keep food safe and use safe water after a natural disaster or emergency.

Clean up your home safely.

• Take steps to protect yourself and your loved ones during cleanup after an earthquake.
• Follow our cleanup tips and monitor your radio or television for up-to-date emergency information.

Stay connected and informed.

• Listen to receive emergency information and instructions from your battery-operated TV or radio, social media, or cell phone text alerts.

• Register to the American Red Cross Safe and Well This lets people know you are okay.
• Save phone calls for emergencies – text messages may be more reliable.

Take care of your emotional health.

During and after an earthquake, it is natural to experience different and strong emotions. Coping with these feelings and getting help when you need it will help you, your family, and your community recover from a disaster.

• Connect with family, friends, and others in your community.
• Take care of yourself and each other and know when and how to seek help.
• Learn more on how to take care of your emotional health after a disaster.

An earthquake is the shifting of the Earth’s plates, which results in a sudden shaking of the ground that can last for a few seconds to a few minutes. Within seconds, mild initial shaking can strengthen and become violent. Earthquakes happen without warning and can happen at any time of year. Certain states are more prone to higher frequency of earthquakes, particularly California, Hawaii, Nevada, and Washington.

Earthquakes are quite common and occur somewhere around the world every day. However, the vast majority are considered minor. The U.S. Geological Survey in 2015 reported more than 3,000 earthquakes in the United States.

Even minor earthquakes that cause little damage and destruction can cause people to experience emotional distress (especially in areas not accustomed to these events). Aftershocks can continue to occur for months afterwards and can be just as stressful.

It’s normal for people to experience emotional distress during an earthquake. Simply anticipating the possibility of what could be lost or destroyed during the event can cause people to experience overwhelming anxiety or lose sleep. Other signs of emotional distress related to earthquakes include:

• Being easily startled
• Having difficulty sleeping or sleeping too much
• Having thoughts and memories related to the earthquake that you can’t get out of your head

Who is at Risk for Emotional Distress?

The following groups are most at risk for emotional distress due to earthquakes:

• Earthquake survivors. People living in impacted areas, particularly children and teens, previously exposed to traumatic, life-threatening situations are especially vulnerable to emotional distress. These people also may have once been displaced.
• Friends and loved ones. It’s normal for friends and family members located outside the impacted area to feel anxious about people who are in direct proximity to an earthquake.
• First responders and recovery workers. These individuals may experience prolonged separation from loved ones (depending on the severity of the earthquake) and show signs of mental fatigue.

Returning to a home, business, school, or place of worship impacted by an earthquake may cause additional distress, especially if there is structural damage. A temporary or permanent loss of employment may also occur.

Remember, too, that the anniversary of a disaster or tragic event can renew feelings of fear, anxiety, and sadness in disaster survivors. Sounds such as sirens or the sight of destroyed buildings or cracks in the walls can also trigger emotional distress among earthquake survivors. These and other environmental sensations can take people right back to the event, or cause them to fear that it’s about to happen again. These “trigger events” can happen at any time.

Creating evacuation plans and gathering emergency supplies before an earthquake occurs can give you a sense of control and help you and your loved ones feel more secure in the event of an earthquake.

People can experience a wide range of emotions before and after a disaster or traumatic event. There’s no right or wrong way to feel. However, it’s important to find healthy ways to cope when these events happen.

An earthquake is a sudden, rapid shaking of the ground caused by the shifting of rocks deep underneath the earth’s surface. Earthquakes can cause fires, tsunamis, landslides or avalanches. While they can happen anywhere without warning, areas at higher risk for earthquakes include Alaska, California, Hawaii, Oregon, Puerto Rico, Washington and the entire Mississippi River Valley.

Prepare Before an Earthquake

The best time to prepare for any disaster is before it happens.

• Practice Drop, Cover, and Hold On with family and coworkers.
• Make an Emergency Plan: Create a family emergency communications plan that has an out-of-state contact. Plan where to meet if you get separated. Make a supply kit that includes enough food and water for several days, a flashlight, a fire extinguisher and a whistle.
  • Being prepared allows you to avoid unnecessary excursions and to address minor medical issues at home, alleviating the burden on urgent care centers and hospitals.
  • Remember that not everyone can afford to respond by stocking up on necessities. For those who can afford it, make essential purchases and slowly build up supplies.
• Protect Your Home: Secure heavy items in your home like bookcases, refrigerators, water heaters, televisions and objects that hang on walls. Store heavy and breakable objects on low shelves.
  • Consider making improvements to your building to fix structural issues that could cause your building to collapse during an earthquake.
  • Consider obtaining an earthquake insurance policy. A standard homeowner’s insurance policy does not cover earthquake damage.

Stay Safe During

If an earthquake happens, protect yourself right away:

• If you are in a car, pull over and stop. Set your parking brake.
• If you are in bed, turn face down and cover your head and neck with a pillow.
• If you are outdoors, stay outdoors away from buildings.
• If you are inside, stay and do not run outside and avoid doorways.

Protect Yourself During Earthquakes

1. Drop (or Lock)

Wherever you are, drop down to your hands and knees and hold onto something sturdy. If you’re using a wheelchair or walker with a seat, make sure your wheels are locked and remain seated until the shaking stops.

2. Cover

Cover your head and neck with your arms. If a sturdy table or desk is nearby, crawl underneath it for shelter. If no shelter is nearby, crawl next to an interior wall (away from windows). Crawl only if you can reach better cover without going through an area with more debris. Stay on your knees or bent over to protect vital organs.

3. Hold On

If you are under a table or desk, hold on with one hand and be ready to move with it if it moves. If seated and unable to drop to the floor, bend forward, cover your head with your arms and hold on to your neck with both hands.

Using a Cane?

Using a Walker?

Using a Wheelchair?

Stay Safe After

There can be serious hazards after an earthquake, such as damage to the building, leaking gas and water lines, or downed power lines.

• Expect aftershocks to follow the main shock of an earthquake. Be ready to Drop, Cover, and Hold On if you feel an aftershock.
• If you are in a damaged building, go outside and quickly move away from the building. Do not enter damaged buildings.
• If you are trapped, send a text or bang on a pipe or wall. Cover your mouth with your shirt for protection and instead of shouting, use a whistle.
• If you are in an area that may experience tsunamis, go inland or to higher ground immediately after the shaking stops. Avoid contact with floodwaters as they can contain chemicals, sewage, and debris.
• Check yourself to see if you are hurt and help others if you have training. Learn how to be the help until help arrives.
  • If you are sick or injured and need medical attention, contact your healthcare provider for instructions. If you are experiencing a medical emergency, call 9-1-1.

Once you are safe, pay attention to local news reports for emergency information and instructions via battery-operated radio, TV, social media or from cell phone text alerts.

• Register on the American Red Cross “Safe and Well” website so people will know you are okay.
• Use text messages to communicate, which may be more reliable than phone calls.
• Be careful when cleaning up. Wear protective clothing, including a long-sleeved shirt, long pants, work gloves and sturdy thick-soled shoes. Do not try to remove heavy debris by yourself. Wear a mask and maintain a physical distance of at least six feet while working with someone else. Use an appropriate mask if cleaning mold or other debris. People with asthma and other lung conditions and/or immune suppression should not enter buildings with indoor water leaks or mold growth that can be seen or smelled. Children should not take part in disaster cleanup work.