Alright, welcome to. Did you just feel that unless it's not earthquakes. My name is Blair Schneider and I am the Outreach Manager for the Kansas Geological Survey.
I'm Leila Joyce. I am a graduate research assistant at the Kansas geological survey.
And so today we're going to talk to you about earthquakes and we have five major learning goals. First, we want to understand what an earthquake is
Identify where earthquakes can occur. And then we're going to give you two case studies. Our first case study is from earthquakes here in Kansas.
And then a second case study looking at the earthquakes in Puerto Rico and lastly of course we're going to teach you what to do if you're in an earthquake. So let's begin.
So what is an earthquake? It's a sudden and violent shaking of the ground as a result of movements within the Earth's crust or volcanic action. This movement releases stress which is energy that's been built up by forces inside the earth. And so if you watch this animation here.
There it is. Our earthquake occurs and it sends these acoustic waves through the interior of the Earth, which creates shaking along the ground.
So here's another animation that gives you an example of how that earthquake occurs here at a plate boundary. So we have one plate that is subducting below the other. I'll go ahead and hit play.
And these plates are moving. So they have the oceanic plates subducting below the continental plate and there's an area where they get locked
So the plates are still moving. But there's an area here where they're actually stuck together. And it's really building up stress and eventually that lock is going to release as you see here, and an earthquake occurs.
The strength of that earthquake depends entirely on the amount of stress that was released at the time.
And another important thing I want to point out about this is if you look at the time frame here in year it's taking hundreds of years for that stress to build up.
And then when that earthquake actually actually happens. It's all happening within about a 30 plus minute time frame.
So where do earthquakes occur? This is a snapshot from Smithsonian mag - definitely check them out! It's a really cool resource.
98% of our earthquakes correspond to the plate boundaries. And so this image that you're looking at here on the left is a map of plate boundaries across the globe.
And this image here again taken from Smithsonian mag is showing you green dots that represent an earthquake of magnitude 4 or greater since approximately 1898
So each of these green dots here you can see pretty much perfectly outlines following these plate boundaries.
So if 98% of earthquakes occur on plate boundaries 2% of them have to occur somewhere else.
So how do we have earthquakes in the central United States? So what I'm showing you here is actually hazard map that was created by the USGS, the United States Geological Survey.
And it shows the probability that ground shaking will exceed a certain level over a 50 year period.
The low hazard areas indicated in gray and blue have a 2% chance of exceeding a designated low level of shaking and high hazard areas which are more of that red, purple color have a 2% chance of topping a much greater level of shaking.
So much more damage at the surface. So here in Kansas, we're pretty much contained within this blue area of hazard level, which is a low level of hazard.
But nearby in the central US, we have this really hotspot area where we have some high hazard. So we're going to look at both of these areas to understand why we're having earthquakes here since we don't exist on a plate boundary in this area.
So this hotspot area is known as the New Madrid seismic zone.
And its really well known because in the winter of 1811-1812
It generated a sequence of Earth earthquakes that lasted for several months and included three very large earthquakes estimated to be between a magnitude 7 and 8.
They destroyed several settelements along the Mississippi River, caused minor structural damage as far away as Cincinnati, Ohio, and St. Louis, Missouri, and they were felt as far away as Hartford, Connecticut, Charleston, South Carolina, and New Orleans.
In this region, it also dramatically affected the landscape. They caused bank failures along the Mississippi River, landslides in Kentucky and Tennessee, and uplift and subsidence of large tracts of land along the Mississippi River floodplain.
At one point, there's a particular area where it actually forced the Mississippi River to flow backwards. That's how extreme these earthquakes,were.
They liquefied subsurface sediment over a large area, resulting in ground fissuring and violent venting of water and sediments.
One account of this phenomena stated that the Pemiscot Bayou "blew up for a distance of nearly 50 miles."
So this is a pretty popular area because we've had some pretty big quakes hit and so they're wondering what's going on here.
So beginning in 1974the USGS installed seismometers. These are instruments that actually measure the ground shaking
And they've recorded thousands of small to moderate earthquakes in northeast Arkansas, southwestern Kentucky, southeast Missouri and northwestern Tennessee and that's what's indicated on this map here.
So what's happening here? So the seismic zone here is about 45 miles wide and about 125 miles long.
The seismic zone is located in the northern part of what has been called the Mississippi Embayment. That's what you're seeing here at the surface.
The upper 30 meters of sediment within this embayment is just sand silts and clays deposited by the rivers and their tributaries over the past 60,000 years. Then just below that you've got a layer of marine sedimentary rocks that are about 50 to 100 million years old.
Below those marine rocks, we have some rocks that are Paleozoic in age. They are sedimentary and they're 570 million years old.
Below those the rocks or even older and we have evidence that about 600 million years ago these rocks became deformed. At that time 600 million years ago, the North American continent almost broke apart.
And during this process of continental rifting, there was a deep valley that formed and it's bounded by faults. It's known as the known as the Reelfoot Rift. And so that's that buried rift here.
So we can identify this as a subsurface system of fractures and faults in the earth crust. So that's what the geology looks like below this region. And so then there's multiple hypotheses as to why we have so much seismic activity here.
One hypothesis suggests that fracturing in this region is resulting from stresses brought on by the down cutting of the Mississippi River into the surrounding landscape.
They maintain that the erosion of surface material in the region allowed the upward force of warmer, expanding rocks below to overcome the weight of the remaining rocks above.
Other hypotheses attribute faulting to the continued rebound of the crust stemming from the most recent ice age. So after those glaciers all melted and retreated back what will naturally happen is the continent will actually start to like rebound or uplift because that weight has been removed.
Another hypothesis is that there is a buildup of pressure within that Reelfoot rift zone located in those crystal rocks underground
So the faults on which the earthquakes occur here are buried beneath 100 to 200 feet thick layers of sot river sediments called alluvium. So we actually can't see them at the surface and that makes it
Harder to observe and harder to track so it leaves a lot of unknown questions. And that's why we have multiple hypotheses to try and explain this question.
So how do we have earthquakes in Kansas? 2% of our earthquakes generally don't occur along the plate boundaries and these are called interplate earthquakes.
And they're produced when rocks beneath the earth's surface suddenly move along faults, which are just fractures that occur along weak points in the earth.
And geological processes, such as the deposition and erosion of surface rock, can actually trigger faults by altering the balance of stresses on the subsurface rocks. So just natural processes can trigger these faults and create stress that builds up and then releases.
In Kansas. We actually do have a few structures that can create natural earthquakes.
So the first one you'll see here is the Nemaha ridge, indicated in a blue here. It runs north to south across Kansas and extends into Oklahoma and into Nebraska.
It's a buried mountain range. It was formed about 300 million years ago and is bounded by faults that are still slightly active today, especially the Humboldt fault zone that forms the eastern boundary of the Nemaha ridge.
About 50 miles west of the Nemaha ridge is the Mid-continent Rift zone, that's indicated by green here.
This is a zone of the earth's continental crust that was ripped apart and filled with oceanic crust, So basaltic rocks, about 1.1 billion years ago.
This zone of rifting extended from central Kansas near Salina, northeastward across Nebraska, Iowa, and Minnesota and all the way up into the Lake Superior region.
We don't know why, but the rifting stops after spreading only about 30 to 50 miles, and if it hadn't stopped eastern Kansas and western Kansas would likely be on different continents today.
So these areas, the mid-continent rift, the Nemaha ridge zone, And then this central Kansas uplift zone, are areas where we have seen natural earthquakes occur.
So here's a summary of the history of earthquakes in Kansas. We do have at least 25 documented earthquakes and by that I mean we have 25 instances where people noticeably felt an earthquake in the state between 1867 and 1976.
But to better understand earthquakes in Kansas, seismologists at the KGS actually maintained a network of seismometers throughout the state beginning in 1977 through June 1989.
This network could pick up ground movements 1000 times smaller than the thickness of a human hair.
So, for example, they could detect artillery firings at Fort Riley from 30 miles away, and it could also register large earthquakes in remote locations as far away as Japan and South America.
So during this 12 years of recording, they recorded more than 200 small earthquakes in Kansas and Nebraska.
The largest one measured about magnitude 4 and the smallest was a magnitude of about 0.8.
The largest recorded Kansas earthquake was centered in Wamego, go east of Manhattan, all the way back in 1867.
It measured seven on the modified Mercalli scale and toppled chimneys, cracked foundations and was felt as far away as Iowa.
So we do have earthquakes in Kansas. They have gotten up into the to the four and five range even more recently, but the level of damage.
Isn't what you would see on like a plate boundary and Leila is going to be talking about that during her portion of the presentation. So while we do see damage from earthquakes in Kansas.
It's a lot different than the type of earthquake you would experience if you were in Puerto Rico, or in California on one of these major plate tectonic boundaries.
So we have another contributor for earthquakes in Kansas, and that's something called induced seismicity
So beginning in 2013 the state saw an increase in seismic activity, particularly in the south central part of the state
This increased shaking raised questions about whether human activity or induced seismicity was to blame.
And so one of our solutions to study that was to install another seismic network. And so we actually have one of our KGS scientists here Shelby Peterie installing one of the seismic network stations.
Out in South Central Kansas.
And here's a map showing you where our seismic network stations are across the state. We currently have 12 in these different counties and we are planning to install six more.
So from this, we learned that in the years 2013 to 2014
Nearly all of the recent earthquakes occurred within two southern counties which you're looking at here, Harper and Sumner County, down here.
This is where we were seeing a large chunk of these earthquakes. So what you're looking at on this map here, the dark dots show the locations of earthquakes reported
By the USGS and the KGS between 1977 through 2012. The orange dots indicate earthquakes reported by the USGS in 2013 and 2014.
And the light green areas are showing you some of those prominent subsurface geological structures.
And so what we're looking at here is when we're dealing with induced seismicity, we also need to consider industry production.
So we're looking specifically at Class I and Class II wells. Currently, the state manages 50 Class I wells. These are deep industrial wastewater wells, so any waste water or kind of waste products can be injected into these deep
underground injection wastewater wells, which are managed by the Kansas. Department of Health and environments and then across the state. We also have approximately 5000 salt water disposal wells. These are called Class II wells and these are managed by the KCC.
Cumulative injection volumes in most areas of the state have been consistent for the past several years, but there was a dramatic change in approved volume increases occurring in South Central Kansas where Harper and Sumner are.
So while I'm talking about well injection, just to clarify that really fast. What you are looking at here is actually a picture where they inject materials into a well
Extraction of oil and gas from underground produces really large volumes of highly saline water.
And so this water after it's extracted is typically disposed of in deep saltwater disposal wells. We're talking thousands of feet below the surface.
And so during this time frame, the annual salt water disposal volume in Harper county increased from the historic rate of about 10 million barrels to more than 100 million barrels by 2015. So this is a huge increase
This is a three to four times increase compared to historical levels for injection
Most of these high-volume wells inject fluid into a rock formation, called the Arbuckle group, which is made up of highly permeable Cambrian to Ordovician age sedimentary rocks.
There's no underlying confining layer in  many places along this unit. And so these rocks are hydraulically linked to the Precambrian granite basement that lies below. These basement rocks typically have many faults, mapped or unmapped
And generally, they have sparse historical earthquake activity. So that's the key thing here, large injection rates that are now coming into contact with Precambrian granite basement below.
So in response to that we did have a regulatory response after discovering this
The KCC ordered reduced injection volumes for salt water disposal wells located within a set of ellipses defined around these high seismicity zones in Harper and Sumner counties.
So you can see right here. These black ellipses here are those high seismicity zones where they ordered reduced rates. So by July 2015 salt water disposal rates were reduced to near the maximum historic rate in this area prior to this uptick in earthquakes.
A year after salt water disposal volumes are restricted earthquake activity within this injection restricted area dropped dramatically. We only had about 250 earthquakes with magnitude 2 or larger in 2016 compared to nearly 800 in 2015. And so here you're seeing
Those earthquakes after these injections were reduced. And you can see a real drop in the number of earthquakes that have occurred.
Now one thing I do want to point out: we have a really common misconception that induced seismicity is because of hydraulic fracturing, often called fracking.
That really isn't accurate. And so I want to make sure we address that misconception here.
So to be clear, the first frac job in Kansas was actually all the way back in 1947. We have been hydraulic fracturing wells since 1947.
But this induced seismicity issue wasn't raised until you know 2013 so historically fracturing of wells has been going on for a long time, but this induced seismicity is just now becoming more prominent.
So I'm going to play a video for you. This is done by Marathon Oil and I think it does a really good job of explaining what happens when a well is hydraulically fractured from start to stop.
Geologists have known for years that substantial deposits of oil and natural gas are trapped in deep shale formations and these shale reservoirs were created 10s of millions of years ago.
Around the world today with modern horizontal drilling techniques and hydraulic fracturing the trapped oil and natural gas and the shale reservoirs is being safely and efficiently produced gathered and distributed to customers.
Let's look at the drilling and completion process of a typical oil and natural gas well
Shale reservoirs are usually one mile or more below the surface well below any underground source of drinking water, which is typically no more than 300 to 1000 feet below the surface.
Additionally, steel pipes called casing cemented in place, provide a multi layered barrier to protect fresh water aquifers.
During the past 60 years the oil and gas industry has conducted fracture stimulations in over 1 million wells worldwide.
The initial steps are the same as for any conventional well the whole is drilled straight down using fresh water based fluids which cools the drill bit.
The bit carries the rock cuttings back to the surface and stabilizes the wall of the well bore. Once the hole extends below the deepest freshwater aquifer.
The drill pipe is removed and replaced with steel pipe called surface casing. Next cement is pumped down the casing.
When it reaches the bottom it is pumped down and then back up between the casing and the borehole wall creating an impermeable additional protective barrier between the well bore and any fresh water sources.
In some cases, depending on the geology of the area and the depth of the well, additional casing sections may be run and like surface casing
Are then cemented in place to ensure no movement of fluids or gas in between those layers and the groundwater sources.
What makes drilling for hydrocarbons in a shale formation unique is the necessity to drill horizontal. Vertical drilling continues to a depth called the kickoff point
This is where the well bore begins curving to become horizontal. One of the advantages of horizontal drilling is that it's possible to drill several wells from only one drilling pad.
Minimizing the impact to the surface environment. When the targeted distance is reached the drill pipe is removed and additional steel casing is inserted through the full length of the well bore.
Once again, the casing is cemented in place. For some horizontal developments, new technology in the form of sliding sleeves and mechanical isolation devices replace cement in the creation of isolations along the well bore.
Once the drilling is finished and the final casing has been installed, the drilling rig is removed and preparations are made for the next step: Well completion.
The first step in completing a well is the creation of a connection between the final casing and the reservoir rock.
This consists of lowering a specialized tool called a perforating gun which is equipped with shaped explosive charges down to the rock layer containing oil or natural gas.
This perforating gun is then fired, which creates holes through the casing summit and into the target rock. These perforating holes connect the reservoir and the well bore.
Since these perforations are only a few inches long and are performed more than a mile underground, the entire process is imperceptible on the surface.
The perforation gun is then removed in preparation for the next step, hydraulic fracturing.
The process consists of pumping a mixture of mostly water and sand mixed with a few chemicals and under controlled conditions into deep underground reservoir formations.
The chemicals are generally for lubrication and to keep bacteria from forming and help carry the sand.
These chemicals typically range in concentrations from 0.1 to 0.5% by volume and help to improve the performance of the stimulation.
Stimulation fluid is sent to trucks that pump the fluid into the well bore and out through the perforations that were created earlier.
This process creates fractures in the oil and gas reservoir rock and the sand in the frack fluid remains in these fractures in the rock and keeps them open when the pressure is relieved.
This allows the previously trapped oil or natural gas to flow to the well bore more easily.
This initial stimulation segment is then isolated with a specially designed plug and the perforating guns are used to perforate the next stage this stage is then hydraulically fractured in the same manner.
This process is repeated along the entire horizontal section of the well, which can extend several miles.
Once the stimulation is complete, the isolation plugs are drilled out and production begins. Initially water and then natural gas or oil flows into the horizontal casing and up the well bore
In the course of initial production of the well approximately 15 to 50% of the fracturing fluid is recovered.
This fluid is either recycled to be used on other fracturing operations or safely disposed of according to government regulations.
The whole process of developing a well typically takes from three to five months, a few weeks to prepare the site, four to six weeks to drill the well, and then 1-3 months of completion activities which includes one to seven days of stimulation
So I'll just pause it there. So you can kind of see with that hydraulic fracturing.
The amount of that explosive I would compare that to you know when they set that off that charge at that kind of a depth.
That's like equivalent to maybe like dropping a gallon of milk on the ground so that activity is not what's contributing to the induced seismicity in Kansas. What we are seeing is that
Like tthey said, when they pulled out that plug the first thing that comes out is water.
So the Groundwater Protection Council estimates that US oil and gas industry generates approximately 3400 billion litres of produced water each year.
So before the oil and gas comes out all of that saltwater or that brine water is actually extracted from the well as and it has to go back underground.
So if they are injecting this wastewater into these disposal wells and they're doing it at too high of an injection rate, it can trigger underlying faults within the subsurface
And I wanted to show you a really cool resource that you have to play with. You can actually explore Kansas earthquakes. If you visit the KGS website at the following link.
You can look at different earthquakes across the state or in particular, counties, you can look at them by year. So right here any earthquake that occurred over a magnitude 2 is indicated for the year of 2016
This would be a great way to kind of explore and play with what's happening across the state. Here is in 2017 all earthquakes over magnitude 2. In 2018 and 2019 also so you know look and see what patterns or trends are you seeing occurring over time.
Right before we move on to Leila's case study let's quickly talk about what to do during an earthquake in Kansas. There's a really cool resource called shakeout
And I'll include the links to these safety video series so you can watch them. But essentially, stop, drop and cover. If you have an earthquake occurring and you're inside, you need to stop, drop and cover.
So if you're indoors. Stay there. Get under a desk or table and hang on to it.
Or move it to a hallway or against an inside wall. Stay clear of windows, fireplaces or heavy furniture, appliances, or things that could fall on you.
Get out of the kitchen. That's actually a really dangerous place. Don't run downstairs or rush outside while the building is shaking or while there's danger of falling and hurting yourself.
If you're outside get into the open. Get away from the buildings, power lines, chimneys and anything else that might fall on you.
And then what about when you're driving a car.
If you're driving stop! but carefully move your car as far out of traffic as possible.
Don't stop on or under a bridge, overpass or under trees, light posts, power lines, again, anything that could fall on top of your car.
And then stay inside your car until the shaking stops and I recommend you know stopping putting your emergency brake on when you do resume driving, make sure to watch for breaks in the pavement fallen rocks, or any other bumps in the road.
And then lastly, if you're in a mountainous area. I know here in Kansas that's not quite the case but you know if your traveling, you do need to make sure to also watch out for falling rock, landslides, trees, etc.
Alright, we're now going to transition over to Leila..
On December 28 2019 Puerto Rico began experiencing a swarm or series of strong shallow earthquakes. The first of magnitude 4.7 shook the south coast of the island and was felt to some degree across much of the territory.
Over the next week, even stronger earthquakes would rock the island, causing power outages and leaving thousands of people homeless. To understand why those earthquakes occurred, let's look at Puerto Rico's tectonic setting.
This slide shows the tectonic plates that influenced the earthquakes in Puerto Rico and the rest of the Caribbean. So we see the North American plate, the South American plate, the Coco's plate and the Caribbean Plate kind of squeezed between them.
The arrows indicate the direction that the plates are moving and the red and yellow dots show earthquake epicenters, you can see that they definitely occur along a lot of those plate boundaries.
So just to help you get yourself kind of oriented as to where we're talking about. Here's the Yucatan peninsula of Mexico.
Here's Cuba, Hispaniola, the island that holds both Haiti and the Dominican Republic. The island of Jamaica and then under this cloud of red and yellow dots is the island of Puerto Rico and the smaller islands of the Caribbean kind of curve down here under this cloud of dots.
So let's zoom in a little bit to look a little bit more closely.
So now we're looking at the northern boundary between the Caribbean Plate and the North American plate.
You can see that rather than being just one line the boundary between the plates is more of a zone. There are several micro plates. See, these three here several micro plates are squeezed between the two larger plates.
In some places like non north of Puerto Rico and south of Puerto Rico and north of Puerto Rico and south of Puerto Rico.
The plates are are being subducted or one is being pulled underneath the other, but in other places like here to the north in the Dominican Republic and Haiti, the plates are kind of grinding past each other. So think about people walking past each other in a really tight crowd.
As you might imagine being squeezed between two larger plates put stress and strain on the microplate that contains Puerto Rico and the US Virgin Islands, which are right here. So if we zoom in even further.
We can see what that stream looks like in terms of fault zones within Puerto Rico. So here we see the island of Puerto Rico and the fault zones that run through it.
So this map only shows where the fault zones appear on land, but it's important to remember that those faults zones do extend down under the down under the ocean.
So we have the Great Northern Puerto Rico fault zone. The Great Southern Puerto Rico fault zone.
And then down here. So as before each of these dots represents an earthquake epicenter with up degrading degrading degrading magnitudes and locations.
So based on what I told you so far, you might think that Puerto Rico is no stranger to earthquakes and you're sort of right
Puerto Rico frequently experiences, earthquakes, but they're either too small for people to feel or just a slight annoyance. Before this year, our last big earthquake occurred over 100 years ago in 1918.
On October 11 1918 a magnitude 7.3 earthquake struck northwest Puerto Rico and was felt strongly across the entire island. The earthquake triggered a landslide under the ocean in the passage between Puerto Rico and the Dominican Republic, which then caused a tsunami.
So within 10 minutes of feeling the earthquake,  the sea pulled back from the shore exposing coral reefs and leaving fish gasping on the sand.
Then a 20 foot wave rushed onto the Northwest and west coast. The earthquake and tsunami killed 116 people, destroyed homes, businesses and small farms that laid near the coast. Aftershocks of the earthquake would continue for over six months.
So here we see several buildings that have been destroyed by the shaking itself. These are brick buildings. So all of these photos are actually from my hometown of Mayaquez on the west coast of Puerto Rico.
These other images here, here and here are homes and businesses that have been literally pulled out to see by the tsunami.
So the epicenter of the 1918 earthquake was just about up here to the northwest of Puerto Rico, so about where that cursor is
And it reverberated down the Great Southern Puerto Rico fault zone.
Our current strong earthquakes or most recent strong earthquakes have their epicenters off the south west coast down here and reverberate along this fault zone.
The first earthquake, a magnitude 4.7 was felt on December 28 of 2019. A magnitude 5.8 followed on January 6 of 2020. Then early in the morning on January 7 2020
A magnitude 6.4 shook everyone awake. This is ATM security footage of the moment that the earthquake struck. So you'll see the man run towards his car to kind of hold on to it. And it's because his young daughter was inside the car.
The three strongest earthquakes, on December 28, January 6 and 7, were accompanied by many, many aftershocks. Schools, homes, historic churches
and geologic features, which you can see here on this slide, collapsed. Thousands of people lost their homes and many more feared sleeping in their homes because they didn't know if it was safe.
People slept in their cars, in tents and makeshift refuges and out in the open if they had to. If they had no other choice. We were also afraid that there would be a tsunami. Thankfully, there wasn't
It's important to note that part of the reason the 2020 earthquakes were felt so strongly and were so devastating to infrastructure is because the epicenters were very shallow
An epicenter of intermediate depth occurs at approximately 87 kilometers below the surface of the air.
The 2020 Puerto Rico earthquakes epicenters were only between one and three kilometers below the surface. The earthquakes were so shallow that people could sometimes hear the waves moving through the rocks below them. It was really very frightening.
Today, Puerto Rico continues to experience small aftershocks the aftershocks will probably continue for months to come.
But even when the aftershocks stop the legacy of these earthquakes will continue.
Satellite imagery showed up to 7 inches of displacement due to the earthquakes. In practical terms, this means the area's closest to the epicenters
are now nearly 7 inches lower in elevation and shifted very slightly to the west. So this image is from NASA was created by NASA from satellite data.
And it shows how much displacement or change occurred in the area of the earthquake epicenters. So areas in red became lower, areas in blue became a little bit higher, just from the movement of these the movement of these earthquakes.
The 7 inches might not sound like a lot of change. But if you have a home or a business that is on a low broad coastline 7 inches is a lot
These photos are of a near shore area in the south coast of Puerto Rico. These are areas that as you might guess were previously on dry sand and reasonably far away from the actual shoreline and now they are shallowly submerged in the ocean.
This video, which is another shakeout video, will give you an idea of what to do in if you are in an earthquake while on the shore.
Reaching up earthquake drills encourage you to practice how to protect yourself during an earthquake, let's learn what to do when you're near the shore.
Along the shore of the ocean you are at risk for a tsunami. Tsunami's are most often created by large undersea earthquakes or landslides as shift the water up or down, sending out waves in all directions.
When these earthquakes are far away, there are several hours before waves arrived. When larger earthquakes happen just off shore of your location.
You may only have a few minutes. In this situation, there are natural warning signs of a potential tsunami.
One such sign is feeling strong earthquake shaking near the shore, whether you areat the beach or in the building immediately drop down onto your hands and knees.
An earthquake is less likely to knock you over in this position, and you are a smaller target for anything falling or flying
Then cover your head with your arms clasp your hands around your neck and bend over to protect your vital organs.
Finally, hold on. Remain on your knees. Close your eyes and mouth to protect against dust and debris. Remain in this position until the shaking stops.
Other natural warning signs of an imminent tsunami is seeing the ocean rise or fall and usually far or hearing a loud roar from the ocean.
So whether you feel strong shaking or observe these other signs immediately evacuate as a tsunami maybe on its way.
If you're in a designated tsunami zone, follow evacuation signs to a safe place. If there are no signs get to high ground or inland away from the water as far as possible.
Walk quickly rather than drive to avoid traffic debris and other hazards. You might also be safe going to a high floor of a sturdy structure.
Unlike a tsunami from a nearby earthquake, a tsunami created by a distant earthquake may not arrive for several hours. It's important to know the first wave is usually not the largest and most dangerous. The danger can last for hours sometimes days.
In this situation, the National Weather Service will issue warnings that are transmitted from your local emergency management department tsunami sirens.
broadcast media and weather radios. If you receive a tsunami warning at or near the shore. Follow the directions of emergency officials.
In order to evacuate. Take your emergency kit and get to high ground or inland away from the water as far as possible. Once you reach a safe place. Stay there.
The tsunami is a series of waves. And the first one is not always the largest
Ocean currents can be dangerously strong, especially in harbors and coastal rivers. Do not leave your evacuation area until you hear from officials that it is safe. Learn more about tsunamis and register your tsunami preparedness activities at tsunamiso.org
Visit shakeout.org to practice earthquake safety with millions of people worldwide and to see videos showing what to do in a variety of situations.
In closing, I want to show you how the waves of the January 7 earthquake rippled across the continental United States. We didn't feel that earthquake in Kansas, but the US array of seismograph absolutely did.
Thanks for listening, everyone.
