Credit: The Virginian-Pilot

What if the February 15, 2013 meteor strike hit the United States, and not Russia? What if it were the size of the meteorite that struck off the coast of Virginia during the age when modern mammals began to appear? What if . . .

A Blast from the Past

About 35 million years ago, an enormous meteorite, a mile or two in diameter and traveling up to 134,000 miles per hour slammed into the shallow Atlantic Ocean where eastern Virginia is today. It vaporized billions of tons of ocean water, melted rocks, cut through a few thousand feet of sediment, and with a catastrophic explosion, created a 24 mile-wide crater. It created a devastating tsunami, scattered tons of sediment along much of the East Coast, and caused glassy particles of solidified melt rock to rain down as far away as Texas.

This explosion was equal to about 10 trillion tons (that’s 10,000,000,000,000) of TNT and is known as the Chesapeake Bay impact crater, the largest crater in the U.S. and the seventh largest in the world. Some of the ejected material, known as ejecta, fell back to the earth, including some that melted and recrystallized into small glass globules called tektites, after the Greek word for “melted.”

“It used to be that people thought that impact craters were extinct volcanoes, even the ones on the moon. But USGS scientists proved there were minerals in these craters that could have only been made by impacts,” said David Powars, a USGS geologist who has been studying the Chesapeake Bay crater for over 25 years.

What was the Effect?

The space debris penetrated through several hundred feet of ocean water and a couple thousand feet of wet sediments. “The enormous blast-splash was about 30 miles high before it collapsed back down,” said Powars.

A map showing the location of the Chesapeake Bay impact crater

The resulting 56-mile diameter complex crater has the shape of an inverted sombrero, with a deep central hole in the crystalline rock. A 1,000- to 4,000-foot-high steep slope marks the outer rim of the crater. In addition there is an approximately 22-mile-wide surrounding area full of faults from the impact, which brings the entire impact crater structure to a diameter of 96 miles. Over the last 35 million years since the catastrophic impact, eastern Virginia has mostly been covered with shallow ocean waters that have buried the crater with fine grain sediments.

Discovering the Impact Crater

The puzzle of the impact crater may have started 135 years ago when the water-well drillers for the Union Army at Fort Monroe, Virginia, worked for five years to drill a 907-foot-deep well, only to find undrinkable, brackish water. But the initial evidence for the crater wasn’t obtained until the mid-1980s, when a core sample was recovered that included 135-35 million-year-old particles of weathered rock and marine plants and animals. Definitive evidence of the crater came in the early 1990s with the release of marine seismic data (a kind of large-scale sonogram) from Texaco and Exxon that provided imagery of the 56-mile complex crater.

The Impact Crater’s Effects on Southeastern Virginia Today

“I think it’s safe to say that without the Chesapeake Bay impact crater the Bay would not look the same today” said Powars. The crater draws the great rivers of the Chesapeake Bay Delta to it, leading to the distinctive shape of the Bay.

The signal from the meteor on February 15, 2013 in Russia was picked up by seismometers in the region that are monitored by the USGS. The attached graphic shows the signal recorded on three seismometers.Small ground motion was observed as far as 4,000 km away from the
explosion.

The crater has affected daily life for area residents – from the early settlers at Jamestown to those who live there today. Until the crater was discovered there was no satisfactory explanation for a bulge of salt water that intrudes into the underground freshwater aquifers of central Virginia. Also historical earthquake data show that four earthquakes align with the outer rim of the crater, including one that occurred in 1995 in York County. All of these factors point to the fact that this 35 million-year-old impact crater is affecting us today.

As frightening as the meteor incident in Russia must have been for those affected, another event like the one that led to the Chesapeake impact crater would have a profound impact on the entire globe. The good news is that scientists are now constantly monitoring objects in space and the effects such objects could and do have when they approach our planet.

Students participate in the Great Southeast ShakeOut earthquake drill at Langston Hughes Middle School in Reston, Virginia. They are conducting the “drop, cover and hold on” safety procedure.

More than 2.7 million people are currently signed up to simulate recommended safety actions during an earthquake in nine states – Tennessee, Oklahoma, Missouri, Alabama, Arkansas, Kentucky, Indiana, Illinois and Mississippi.

You are invited to join millions of people who will Drop, Cover, and Hold On at 10:15.a.m. on February 7, 2013* in the 2013 Great Central U.S. ShakeOut!

Last year more than 12.5 million people were registered in ShakeOut drills worldwide. Participating is a great way for your family or organization to be prepared to survive and recover quickly from big earthquakes.

During the drill, participants will “drop, cover, and hold on.” This is the recommended safety action to take during an earthquake.

Millions of people have participated in ShakeOut drills since 2008. The drill is your chance to practice how to protect yourself and do your part to help prevent a major earthquake from becoming a catastrophe.

Earthquake Hazard in the Central U.S. Remains a Concern

There is broad agreement in the scientific community that a continuing concern exists for a major destructive earthquake in the New Madrid seismic zone. Many structures in Memphis, Tenn., St. Louis, Mo., and other communities in the central Mississippi River Valley region are vulnerable and at risk from severe ground shaking. This assessment is based on decades of research on New Madrid earthquakes and related phenomena by dozens of Federal, university, State, and consulting earth scientists.

This will be the third year an earthquake preparedness drill is officially held in the central United States. Even if you don’t live in one of these locations, this is an important exercise as earthquakes are a hazard worldwide. Keep in mind that you might travel somewhere where an earthquake could occur. Everyone, everywhere, is encouraged to participate in the ShakeOut.

Sign Up and ShakeOut

Although the ShakeOut is TOMORROW, it is not too late to register to participate. Mark your calendar and register for the ShakeOut drill near you. Families, schools, businesses, and organizations can all get involved and sign up.

There are many ways to participate, and a variety of resources and tips are provided online. This includes pre-made flyers, drill broadcast recordings, drill manuals, and more.

What to Do During the Drill

The drill will begin at 10:15 a.m. local time. If you are indoors, you should “drop, cover, and hold on.” Drop to the floor, take cover under a sturdy desk or table, and hold on to it firmly. If you are not near a desk or table, drop to the floor against the interior wall and protect your head and neck with your arms. Avoid exterior walls, windows, hanging objects, mirrors, tall furniture, large appliances, and kitchen cabinets with heavy objects or glass.

While down on the floor, take a moment to look around at what could be falling during a real earthquake. Those items should be secured or moved after the drill.

During an earthquake, the recommended safety action is to “drop, cover, and hold on.”

If you happen to be outdoors, move to a clear area if you can safely do so. Avoid power lines, trees, signs, buildings, vehicles, and other items that could fall on you. If you are driving, pull over to the side of the road, stop, and set the parking brake. Avoid stopping under overpasses, bridges, power lines, or traffic signs. Stay inside the vehicle until the shaking is over.

USGS Science in ShakeOut

The U.S. Geological Survey (USGS) is a proud founder and supporter of ShakeOut.

Students participate in the Great Southeast ShakeOut earthquake drill at Langston Hughes Middle School in Reston, Virginia. They are conducting the “drop, cover and hold on” safety procedure.

The USGS has created and provides information tools to support earthquake loss reduction, including hazard assessments, scenarios, comprehensive real-time earthquake monitoring and public preparedness handbooks. USGS science provides the basis for earthquake scenarios that shape preparedness exercises such as the ShakeOut. USGS earthquake hazards research helps emergency managers understand where earthquakes occur and what the potential damages and losses would be.

The original ShakeOut was based on a comprehensive analysis of a major earthquake in southern California known as “The ShakeOut Scenario.” That project was completed in 2008 and led by the USGS with many partners as a demonstration of how science can be applied to reduce risks related to natural hazards. The concept and organization of a public drill came out of the collaboration between the USGS, the Southern California Earthquake Center (SCEC), and other partners through the Earthquake Country Alliance (ECA). SCEC is a research consortium funded in part by the USGS. ECA is a public-private partnership of people, organizations, and regional alliances that are led by SCEC and work together to improve preparedness, mitigation, and resiliency by supporting and coordinating efforts that improve earthquake and tsunami resilience.

The success of the 2008 ShakeOut spurred the organizers at ECA to take the concept worldwide, and turn it into an annual day of disaster preparedness activities. Nationwide, ShakeOut activities are now coordinated and supported by many agencies and partners including SCEC, the Federal Emergency Management Agency (FEMA), the National Science Foundation (NSF), the Central United States Earthquake Consortium (CUSEC), the American Red Cross, and others.

The USGS provides rapid alerts of potential impacts from an earthquake through its Prompt Assessment of Global Earthquakes for Response (PAGER)  system. Sign up to receive earthquake notices through the USGS Earthquake Notification System. If you feel an earthquake, report your experience on the USGS “Did You Feel It?” website.

Learn More

Students participate in the Great Southeast ShakeOut earthquake drill at Langston Hughes Middle School in Reston, Virginia. They are conducting the “drop, cover and hold on” safety procedure.

Learn how to prepare at home using the 7 Steps to Earthquake Safety from “Putting Down Roots in Earthquake Country” written for different areas of the country and in several languages.

Find out more about why the Earthquake Hazard in the New Madrid Seismic Zone Remains a Concern.

Additional information on what you can do to prepare for earthquakes at work and home is available on the Great ShakeOut website.

USGS CoreCast

ShakeOut Drill: Preparing for Earthquakes

Recorded for the October 18, 2012 Great ShakeOut held in the southeastern United States.

Transcipt and Details

•  Start with Science to Address Vulnerable Coastal Communities
• Hurricane Sandy Coastal Change Hazards
• Predicted Likelihood of Coastal Change Impacts from Hurricane Sandy
• Hurricane Sandy Storm Tide Data and Mapper
• Water-Quality Sampling Immediately After Hurricane Sandy
• Real-Time Monitoring: Rapid deployment storm tide sensors and streamgages, and permanent streamgages in Sandy impact area
• USGS Issues Landslide Alert for Hurricane Sandy
• WaterWatch: View streamflow during Hurricane Sandy (Oct 29 and subsequent days)

• Coastal Change Hazards: Hurricanes and Extreme Storms
• Coastal Elevation Data: Access National Elevation Dataset and other coastal elevation information
• Sustainable Estuaries, Coastal, Urban, and River Enviroments
• Ready.gov

More than 160 USGS scientists, technicians, and specialists are responding to Hurricane Sandy’s aftermath, from Virginia to Massachusetts. Crews from USGS are working hard to retrieve data for emergency managers.

Hurricane Sandy’s impacts have been significant. Many USGS tidal sensors recorded peaks of record and several were completely overtopped. In addition, high-water marks flagged by USGS crews show sizeable storm surge, including 18.98 feet at Long Branch, NJ; 12.93 feet at the Verazzano Narrows Bridge between Brooklyn and Staten Island, NY; and 7.43 feet at Lindenhurst on Long Island, NY.

USGS scientist recovers storm surge sensor in Annapolis, MD.

Storm-Surge Sensors

USGS crews are currently out retrieving the more than 150 storm-surge sensors that were deployed prior to Sandy’s landfall. These sensors extended from the mouth of the Chesapeake Bay in Virginia to the coast of Maine.

The data from these sensors will be used to create models of the precise time the storm-tide arrived, how ocean and inland water levels changed during the storm, the depth of the storm-tide throughout the event, and how long it took for the water to recede.

This information gathered is being used to assess storm damage, discern between wind and flood damage, and improve computer models used to forecast future coastal change.

All data collected by these sensors and the existing USGS streamgage network are available on the USGS Storm-Tide Mapper.

High-Water Marks

In addition, at the request of FEMA, USGS scientists are marking high-water marks. Crews in New York currently have 150 sites they are checking, many established in the 1992 Noreaster that struck the Long Island area. New Jersey crews have an additional 100 sites they are checking along the Atlantic shoreline as conditions are safe to do so. USGS scientists from Maryland, Delaware, Connecticut, and Rhode Island are also be looking for high-water marks in their areas.

USGS scientist Kerry Caslow using RTN GPS surveying to establish an elevation for a storm-tide sensor in New Jersey. Photo credit: Chris Smith, USGS.

High-water marks serve a very important function in assessing damage. USGS crews look for sustained high-water marks, meaning indications of the highest level the water stayed for a time. Because water-levels change often due to wave action, sustained high-water marks allow USGS scientists to determine the levels the water stayed at long enough to cause significant impacts.

High-water marks are useful in determining the amount of damage sustained due to flooding and storm surge. Impact models use high-water marks to determine likely levels of damage to a building’s structural integrity, as well as potential scour damage. Scour damage is the abrasive erosion caused by dissolved solids in water rubbing against buildings or other structures that can wear away the surface, eventually leading to instability.

In addition, FEMA uses high-water marks to determine what damage comes from wind and what damage comes from water when formulating their own impact models.

Coastal Change

In addition, USGS crews have returned to coastal New Jersey and Long Island to do lidar surveys for before and after studies of coastal change, using the pre-storm lidar surveys taken October 26^th and 27^th.

Also, USGS crews will conduct aerial surveys from Cape Hatteras, North Carolina, to Montauk, New York. These surveys will include oblique aerial photography and lidar topography. The photographs will be compared to pre-storm photography for a qualitative look at coastal erosion, while the lidar data will be compared to pre-storm beach elevations to quantify actual changes in the beach, such as dune erosion and overwash.

Water Quality

USGS crews have also performed water quality sampling at various locations, including the Delaware River near Trenton, New Jersey; from the Potomac River and the Eastern Shore in Maryland; various sites in Washington, DC, and sites throughout Northern Virginia.

Oblique aerial photographs of Fire Island, New York, at Pelican Island before and after Hurricane Sandy impacts shows coastal change on an undeveloped coastline.

Oblique aerial photographs of Seaside Heights, New Jersey, before and after Hurricane Sandy impacts shows coastal change on a developed coastline.

• Hurricane Sandy Storm Tide Mapper (accessible version and web services)
• Water-Quality Sampling After Hurricane Sandy
• USGS Issues Landslide Alert for Hurricane Sandy
• Real-Time Monitoring Sites
• Coastal Elevation Data and Research
• Coastal Change Hazards: Hurricanes and Extreme Storms
• Flood Information
• WaterWatch
• Ready.gov

***Updated: coastal change section edited from original, based on an updated assessment from October 29, 2012***

As millions of northeast residents bought water, batteries and food this weekend in preparation for Hurricane Sandy, USGS scientists, engineers, and technicians worked up and down the Atlantic Coast, deploying storm-surge sensors and maintaining real-time streamgages in preparation for Hurricane Sandy’s arrival.

Storm-Surge and Real-Time Sensors

USGS Storm-Tide Mapper, showing all data collected by the storm-surge sensors and the USGS streamgage network.

Much of the work involved installing more than 150 storm-surge sensors along the Atlantic coast, from the mouth of the Chesapeake Bay to Massachusetts. These sensors, which measure water elevation every 30 seconds, augment an already robust network of coastal and inland streamgages in place to monitor water levels throughout the storm.

A USGS scientist installs a storm-surge sensor for Hurricane Rita in 2005, the first storm in which these sensors were deployed.

In addition, eight of the recently deployed sensors are Rapid Deployment Gages, which provide real-time information to help forecast floods and coordinate flood-response activities in affected areas. These real-time gages will complement the many near real-time streamgages already installed along rivers and streams.

All data collected by these sensors and the existing USGS streamgage network are available on the USGS Storm-Tide Mapper.

Working with various partner agencies such as NOAA, FEMA, and the U.S. Army Corps of Engineers, the USGS strapped the storm-surge sensors – typically about 1 ½ inches wide and a foot long – to piers, docks or other structures in the water expected to withstand the storm.

They record the precise time the storm-tide arrived, how ocean and inland water levels changed during the storm, the depth of the storm-tide throughout the event, and how long it took for the water to recede.

This information gathered will be used to assess storm damage, discern between wind and flood damage, and improve computer models used to forecast future coastal change.

Anticipated Coastal Change

Probabilities of collision, overwash, and inundation for Sandy for the Atlantic coast of Delmarva.

Elevated water levels and waves during tropical storms can lead to dramatic coastal change of beaches and dunes. The USGS has completed an assessment of likely coastal-change impacts from Hurricane Sandy.

Nearly 91 percent of the coast along the Delmarva Peninsula is very likely to experience beach and dune erosion from the storm, while overwash is expected to affected more than  half of the shoreline, and 22 percent of the beaches are expected to experience inundation by waves and storm surge   In these areas, waves and storm surge transport large amounts of sand across coastal environments, depositing sand both inland and offshore, causing significant changes to the landscape.

Overwash, the landward movement of large volumes of sand from overtopped dunes, is forecasted for portions of the east coast with the projected landfall of the storm. The severity of overwash depends on the strength of the storm, the height of the dunes, and how direct a hit the coast takes.

Probabilities of collision, overwash, and inundation for Sandy for the Atlantic coast of New Jersey

The models show that along the New Jersey shore, 98 percent of the coast is very likely to experience beach and dune erosion, while 54 percent is very likely to experience overwash, and 9 percent to experience inundation.

It also indicates that on the south shore of Long Island, N.Y., including Fire Island National Seashore, 93 percent of the coast is very likely to experience beach and dune erosion, 12 percent to experience overwash, and 4 percent to experience inundation; the lower percentages of overwash and inundation in these areas is because of the relatively high dune elevations.

The impact of previous storms on sandy beaches along the mid-Atlantic Coast has made them increasingly vulnerable to significant impacts such as erosion.

Beaches and dunes often serve as the first line of defense for coastal communities against flooding and other hazards associated with extreme storms.

Probabilities of collision, overwash, and inundation for Sandy for the southern coast of Long Island

Any compromise to these features means that storm-related hazards are more likely to threaten coastal property, infrastructure, and public safety during a future extreme storm event.

• Hurricane Sandy Storm Tide Mapper (accessible version and web services)
• Water-Quality Sampling After Hurricane Sandy
• USGS Issues Landslide Alert for Hurricane Sandy
• Real-Time Monitoring Sites
• Coastal Elevation Data and Research
• Coastal Change Hazards: Hurricanes and Extreme Storms
• Flood Information
• WaterWatch
• Ready.gov

The current NOAA forecast for Hurricane Sandy’s track. USGS is ready to deploy sensors along the Atlantic coast to measure storm tide height.

The U.S. Geological Survey is keeping careful watch as Hurricane Sandy continues to track northeast along the east coast of Florida and the Atlantic coast.  Along with federal partners, the agency is taking actions to help minimize potential risks to lives and property.

Before, during and after any hurricane or tropical storm affecting the United States, the USGS is involved in measuring the height and intensity of the storm surge, and monitoring water levels of inland rivers and streams, providing critical information used to forecast floods.  Using state-of-the-art modeling, the USGS is also involved in forecasting coastal change caused by storm surge, assessing the likelihood of beach erosion, overwash or inundation.

USGS Streamgaging Network at the Ready

The USGS, in cooperation with local, state and federal agencies, operates long-term sensor networks on inland rivers and streams throughout the nation. These networks provide real-time data important to the National Weather Service, FEMA, the U.S. Army Corps of Engineers, and other USGS partners involved in issuing flood and evacuation warnings, coordinating emergency responses to communities, and operating flood-control reservoirs.

The USGS streamgaging network is primed and ready to go for Hurricane Sandy, no matter where the storm finally makes landfall.

Data from the USGS Streamgaging Network are routinely used for water supply and management, monitoring floods and droughts, bridge and road design, determination of flood risk, and for many recreational activities. However, during a storm’s landfall, this network helps capture the depth and duration of storm-surge, as well as the forecasted time of its arrival and retreat.  Understanding storm surge allows for more accurate modeling and prediction capabilities and for improved structure designs and response for public safety. Inland streamgages also are used to track the rainfall and flooding caused by the remnants of the storm.

USGS crews are on alert.  Immediately after the worst of the storm has passed, USGS hydrologists will deploy to measure high-water marks at rivers and streams and to verify high river flows and peak stages. The crews will also calibrate and repair streamgages damaged by the storm to ensure they continued to transmit information in real time to users working to protect lives and property.

USGS Deploys Additional Storm Surge Sensors on the Atlantic Coast

Figure 2. USGS storm surge sensor deployed for Hurricane Isaac earlier this year. USGS installed more than 200 sensors in preparation for Isaac’s landfall, to measure and record storm surge height and power.

Storm surges are increases in ocean water levels generated at sea by extreme storms and can have devastating coastal impacts.  Prior to extreme weather events, the USGS may also deploy storm surge sensors at key coastal locations just a few days – or sometimes hours — before a Hurricane or Tropical Storm’s anticipated landfall. These storm surge sensors, housed in vented steel pipes a few inches wide and about a foot long, are installed on bridges, piers and other structures that have a good chance of surviving a storm surge during a hurricane. The number of sensors installed and their locations depend on the strength of the storm as well as what gages may already be in place.

In preparation for Hurricane Sandy, the USGS is ready to install additional sensors along the Atlantic coast, from Virginia to Massachusetts.  These sensors can record water level and barometric pressure every 30 seconds to document storm-surge crests – or waves of water – as they make landfall.

Storm tide sensors were previously deployed along the Atlantic coast in preparation for Hurricane Irene, in 2011. The data they collected were instrumental in understanding the effects of hurricanes and tropical storms on the East Coast.

Together, the USGS Streamgaging Network and the mobile USGS storm surge sensors provide critical data to the National Weather Service, FEMA and other USGS partners involved in issuing flood and evacuation warnings and in coordinating emergency responses to communities. In the event of a large tropical storm event, storm surge information will also help public officials assess storm damage, discern between wind and flood damage, and improve computer models used to forecast future floods.

Monitoring Coastal Change

Overwash, which occurs when waves and storm surge overtop dunes and transport sand landward, is a likely impact of hurricanes and tropical storms. The severity of erosion and overwash depends on the strength of the storm, beach elevation, and how direct a hit the coast takes.

While it’s difficult to tell where exactly the storm is headed or what its impacts may be, USGS scientists are using state-of-the art models to give emergency managers and local residents an accurate picture of what coastal changes are likely to occur if Hurricane Sandy makes landfall along the Atlantic coast.

Using the same system that modeled coastal impacts from Hurricane Isaac earlier this year, USGS scientists will post interactive maps using data on coastal features and models of hurricane waves and surge to predict the likely impact of Hurricane Sandy to the coast.

Tracking River Levels in Real Time

All information from USGS Nationwide Streamgaging network can be accessed at the USGS WaterWatch website. In a storm, this information can be particularly useful to local residents who want to know how increased rainfall from tropical storm Isaac will impact the rivers and stream in their areas. This site displays maps, graphs and tables that describe current and past streamflow conditions for the United States. The real-time streamflow data are generally updated on an hourly basis.

WaterAlert also allows users to receive updates about groundwater levels, water temperatures, rainfall and water quality at sites where USGS collects real-time water information.

For information on the latest storm track, listen to NOAA radio.  For information on preparing for the storm, go to Ready.gov or Listo.gov.

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Children participating in an earthquake drill on April 23, 2009, at the British School in Tokyo, Showa Campus. The drill is based on the Japanese Earthquake Early Warning System.

During the drill, participants will “drop, cover, and hold on.” This is the recommended safety action to take during an earthquake.

Millions of people have participated in ShakeOut drills since 2008. The drill is your chance to practice how to protect yourself and do your part to help prevent a major earthquake from becoming a catastrophe.

This will be the first year an earthquake preparedness drill is officially held in the southeastern United States. The Great Southeast ShakeOut includes Georgia, South Carolina, North Carolina, Virginia, Maryland, and the District of Columbia. Official ShakeOut drills will also be held on October 18 in Alaska, Arizona, British Columbia, California, Guam, Idaho, Nevada, Oregon, Puerto Rico, southern Italy, and Washington.

Even if you don’t live in one of these locations, this is an important exercise as earthquakes are a hazard worldwide. Keep in mind that you might travel somewhere where an earthquake could occur. Everyone, everywhere, is encouraged to participate in the ShakeOut.

Sign Up and ShakeOut

Although the ShakeOut is just days away, it is not too late to register to participate. Mark your calendar and register for the ShakeOut drill near you. Families, schools, businesses, and organizations can all get involved and sign up.

There are many ways to participate, and a variety of resources and tips are provided online. This includes pre-made flyers, drill broadcast recordings, drill manuals, and more.

What to Do During the Drill

The drill will begin at 10:18 a.m. local time. If you are indoors, you should “drop, cover, and hold on.” Drop to the floor, take cover under a sturdy desk or table, and hold on to it firmly. If you are not near a desk or table, drop to the floor against the interior wall and protect your head and neck with your arms. Avoid exterior walls, windows, hanging objects, mirrors, tall furniture, large appliances, and kitchen cabinets with heavy objects or glass.

While down on the floor, take a moment to look around at what could be falling during a real earthquake. Those items should be secured or moved after the drill.

During an earthquake, the recommended safety action is to “drop, cover, and hold on.”

If you happen to be outdoors, move to a clear area if you can safely do so. Avoid power lines, trees, signs, buildings, vehicles, and other items that could fall on you. If you are driving, pull over to the side of the road, stop, and set the parking brake. Avoid stopping under overpasses, bridges, power lines, or traffic signs. Stay inside the vehicle until the shaking is over.

USGS Science in ShakeOut

The U.S. Geological Survey (USGS) is a proud founder and supporter of ShakeOut.

The USGS has created and provides information tools to support earthquake loss reduction, including hazard assessments, scenarios, comprehensive real-time earthquake monitoring and public preparedness handbooks. USGS science provides the basis for earthquake scenarios that shape preparedness exercises such as the ShakeOut. USGS earthquake hazards research helps emergency managers understand where earthquakes occur and what the potential damages and losses would be.

The original ShakeOut was based on a comprehensive analysis of a major earthquake in southern California known as “The ShakeOut Scenario.” That project was completed in 2008 and led by the USGS with many partners as a demonstration of how science can be applied to reduce risks related to natural hazards. The concept and organization of a public drill came out of the collaboration between the USGS, the Southern California Earthquake Center (SCEC), and other partners through the Earthquake Country Alliance (ECA). SCEC is a research consortium funded in part by the USGS. ECA is a public-private partnership of people, organizations, and regional alliances that are led by SCEC and work together to improve preparedness, mitigation, and resiliency by supporting and coordinating efforts that improve earthquake and tsunami resilience.

The success of the 2008 ShakeOut spurred the organizers at ECA to take the concept worldwide, and turn it into an annual day of disaster preparedness activities. Nationwide, ShakeOut activities are now coordinated and supported by many agencies and partners including SCEC, the Federal Emergency Management Agency (FEMA), the National Science Foundation (NSF), the Central United States Earthquake Consortium (CUSEC), the American Red Cross, and others.

USGS employees across the nation are signing up to participate in the drill, raising awareness and providing an opportunity to test occupant emergency plans.

The USGS provides rapid alerts of potential impacts from an earthquake through its Prompt Assessment of Global Earthquakes for Response (PAGER)  system. Sign up to receive earthquake notices through the USGS Earthquake Notification System. If you feel an earthquake, report your experience on the USGS “Did You Feel It?” website.

Podcast

Listen to a podcast interview on ShakeOut. The interview is with Mike Blanpied, who is the Associate Program Coordinator for the USGS Earthquake Hazards Program, as well as Mark  Benthien, who is the Director of Communication, Education and Outreach with SCEC and coordinates the Great ShakeOut worldwide.

Learn More

Learn how to prepare at home using the 7 Steps to Earthquake Safety from “Putting Down Roots in Earthquake Country” written for different areas of the country and in several languages.

News media can also find information online regarding events, contacts and other items of interest.

Additional information on what you can do to prepare for earthquakes at work and home is available on the Great ShakeOut website.

I’m Robert Leeper, a senior Bachelor of Science student majoring in geology at California State University, Fullerton. While attending Cerritos College in 2007, I applied for an internship at the Southern California Earthquake Center. During my internship, I was assigned to work with the USGS Multi-Hazards Demonstration Project, on the Great Southern California “ShakeOut” earthquake scenario. Following my internship, I was offered the opportunity to work for the USGS as a student employee under a Student Temporary Employment Program appointment, and I happily accepted. I am now a member of the USGS’s Science Application for Risk Reduction (SAFRR) team. SAFRR will aid in applying natural hazard science to improving the safety, security and economic well-being of the nation.

A Day in the Life

When I am not conducting field research, I am analyzing data recorded in a trench along the San Andreas Fault. I investigate spatial reference points using a computer program in order to identify stratigraphy that has been exposed by the trench. When an earthquake occurs, stratigraphy along the fault can be offset, and measuring the offset helps provide a better understanding of earthquake magnitude. When the stratigraphic layers are dated and those data are combined with earthquake magnitude data from the stratigraphy measurements, the magnitude and frequency of earthquakes on that fault become better understood. I am also working on creating photo-mosaics from a San Andreas Fault trench and preparing them for analysis. In addition, I’m writing a paleotsunami deposit fact sheet — a paleotsunami is a tsunami that occurred before the historical record, or a tsunami for which there is no written record.

This picture was taken while I was conducting post-storm debris-flow reconnaissance. The fault was covered by vegetation and sediment prior to the storms that hit the area after the Station Fire. To me, the small fault segment and the entire mountain range I was working in symbolized yet another, more well-known geologic hazard that residents of southern California face: earthquakes. While working in the field, I try to decipher and understand as much geology as I can.

I work with a team of scientists on a study that aims to identify a chronology of paleotsunami events along the California coast. At present, we are in the reconnaissance phase of the study, probing the subsurface in salt marshes and estuaries for anomalous and laterally continuous “beach” sand layers that could mean a paleotsunami occurred there. Once we identify sites of interest, we will conduct more in-depth studies and laboratory analyses.  The result of all this is that a better understanding of how often tsunamis have hit the California coast in the past will emerge. And of course, past events are an indication of what could happen in the present and the future. Consequently, the final results of the study will be used by the state of California to better assess its tsunami hazard; this research will also be incorporated by the SAFRR into our next hazard scenario.

Contributing to Science

The largest wildfire in Los Angeles County history, The Station Fire, burned in the mountains north of Los Angeles in late 2009. This wildfire greatly increased the danger of debris flows in subsequent storm seasons. After the fire and through 2011, I contributed to the development of a method that provided data on the timing of post-fire debris flows relative to rainfall.  Debris flows are fast-moving landslides that occur in a wide variety of environments throughout the world. They are particularly dangerous to life and property because they move quickly, destroy objects in their paths, and often strike without warning. After the fire, I installed, maintained and monitored real-time debris flow data-acquisition stations within the fire perimeter. As storms passed over the burned area, I was a point of contact that provided status reports from the field so other USGS personnel could forward the data to emergency management officials. Also, I am proud to say that I am coauthor of a peer-reviewed paper that presents the debris-flow timing data our team collected. The paper has been approved and scheduled for publication soon.

This photo was taken on the morning of February 6, 2010, shortly after the Mullally debris basin was filled to capacity and breached by debris flows. The photo shows a house that was destroyed by debris flows. The water heater and tan wall on top of the car are from the house that is to the left of the field of view (not in the photo). Debris, such as boulders, mud and tree stumps, are shown inside the house, which had a good portion of its walls and windows blown out.

My favorite experience with the USGS so far was responding to the debris-flow events of February 6, 2010; these events occurred in the foothills of the San Gabriel Mountains north of Los Angeles. I was called to the scene after debris flows breached containment basins and inundated the communities situated below them. When I saw the destruction and unimaginable power of the debris flows, my respect for the diversity and severity of geo-hazards was taken to a new level. Other memorable moments with the USGS include conducting media interviews while in the field conducting emergency debris-flow response during storms. I actively helped piece together and solve real-world geologic-hazard problems alongside professional scientists. Deciphering the complicated processes behind geologic hazards makes our world a safer place.

The Greater Good

I find great satisfaction in knowing that the work I am doing helps humanity understand geologic hazards better, which in turn makes all of our lives safer. I hope to continue working for the USGS once I start graduate school in the spring of 2013. After I complete graduate school, I would like to have a career with the USGS. Working for the USGS has provided me with invaluable field and laboratory research experience.

Every day, I gain an understating of what it takes to manage a successful long-term research project and to see it through to fruition. I would like people to know that the USGS is an organization that conducts research for the betterment of humanity. Whether it is research on groundwater quality or on earthquake early warning systems, the scientists at the USGS are conducting research that benefits us all.    

Robert Leeper being interviewed by the media during a storm. Residents of the affected communities and the media wanted to know how the mountains were holding up and if any debris flows had occurred during the current storm. It turned out that no debris flows were recorded during this particular storm because the intense rainfall did not pass over the burned area as had been forecasted earlier that day.

The ground in Japan began rumbling March 9, 2011, with a series of large foreshocks measuring over magnitude 6 and peaking at magnitude 7.2. But it was not until two days later that the main event, which would trigger the tsunami responsible for the bulk of the destruction, occurred. At magnitude 9.0, the massive earthquake is world’s fifth largest earthquake since 1900. In Japan, it is the largest since modern instrumental recordings began 130 years ago. The tsunami even caused over $50 million in damage to nearly two dozen harbors in California.

Strong shaking lasted three to five minutes in some places. The tsunami damaged the Fukushima I Nuclear Power Plant, disabling the emergency generators needed to cool reactors and leading to nuclear meltdowns and radiation leaks. William Ellsworth, of the USGS Earthquake Science Center in Menlo Park, Calif., says photos and video of the tsunami will provide powerful evidence of the implications of hazard risk around the globe. “I no longer need to explain to anyone the power of, or danger posed by, a tsunami,” he said.

This USGS ShakeMap shows shaking intensity along the east coast of Japan during the March 11 magnitude 9.0 earthquake.

In the United States, scientists and staff at the USGS’s National Earthquake Information Center, which monitors all significant global earthquakes, began working around the clock as the Tohoku earthquake and its resulting tsunami occurred. They quickly produced products for emergency responders, the public, the media, and the academic community about the earthquake’s potential impact and damages, as well as provided scientific background for the interpretation of the event’s tectonic context and potential for future hazards.

When the shaking and tsunami subsided, they left staggering destruction behind. Japan reported around 20,000 casualties, making the event the 20^th most deadly earthquake and tsunami in the past 100 years. In addition, the country experienced $200-300 billion in property and infrastructure losses, an economic toll that will affect Japan for years to come.

Experts note, however, that most of the losses were caused not by the quake itself, but by the unexpectedly large tsunami. They estimate that fewer than 5 percent of the damage came from the earthquake, due to Japan’s investment in infrastructure, engineering, and preparedness. Engineered buildings performed well under the high shaking levels, and the Japanese Earthquake Early Warning system provided up to 90 seconds’ warning of the earthquake for some residents in Tokyo.

Lessons from Tohoku

Altough the Tohoku quake did not occur in the United States or its territories, it was one of the most thoroughly recorded seismic events of its magnitude and provides valuable information to U.S. scientists seeking to understand how similar events would affect this Nation.

Tom Brocher, center director for the USGS Earthquake Science Center in Menlo Park, said, “The investment by the Japanese government in earthquake monitoring instrumentation yielded an unprecedented scientific and engineering data bonanza that will help the Japanese to mitigate damage from future earthquakes.”

For example, these data mean that scientists now know more about the probability of similar earthquakes and the potential size of their resulting tsunamis. An unparalleled amount of strong ground motion data were recorded that will help reduce uncertainty in seismic hazard assessments in Japan and elsewhere.

Researchers also know more about the effects of such earthquakes. For example, many cases of liquefaction were witnessed and filmed for the first time. Liquefaction occurs when soil loses strength and stiffness due to an applied stress like an earthquake and behaves like a liquid, often causing damage to structures and infrastructure.

Seismologists across the globe were surprised by the magnitude of shaking that occurred in the segment of fault responsible for the Tohoku quake. Japanese scientists had not believed a quake of such intensity could occur in that area, which in turn impacted tsunami strength estimates. According to Brocher, the tsunami defenses in the area were built in the event of a tsunami resulting from a magnitude 8.0 earthquake, not a 9.0.

This USGS ShakeMap shows projected shaking along the West Coast in the event of a magnitude 9.0 earthquake occurring along the Cascadia Subduction Zone.

Thus, even though the Japanese had planned and were well-prepared for a 200- or 300-year tsunami, they were not prepared for the 1000-year tsunami (an event that’s likely to occur just once every 1,000 years) that came instead. Consequently, Japan is currently updating its tsunami disaster plans for all of its coastal areas and requiring that all plans take evidence from paleo-tsunami deposits into consideration.

Paleo-tsunami deposits are the sand and mud that tsunamis leave behind. By studying deposits from recent events like the March 11 tsunamis, scientists are able to develop criteria for what those deposits look like and use them to examine coastal areas for records of tsunamis that struck centuries back. They can tell when tsunamis occurred and how far inland they reached by looking at the evidence left behind.

USGS coastal and marine geologists Bruce Jaffe, Bruce Richmond, and Rick Wilson have worked with Japanese scientists over the past year to study these deposits in Japan. Said Jaffe, “Japan has learned from this tsunami that it’s necessary to look at the geologic evidence for tsunamis in conjunction with the current understanding of earthquake potential to accurately assess the future tsunami hazard.” He explained that “Each tsunami brings its own sand and mud. Japan recognizes the value of using the very rich record of past tsunamis to help us understand the hazard for future tsunamis.”

The United States is also conducting its own paleo-tsunami deposit studies in California, Alaska, the Caribbean, Puerto Rico, and the Virgin Islands to better understand the tsunami risk in those areas.

This image shows fish and mud deposited from the tsunami on the road ringing Kawaihae Harbor in Hawaii on Saturday, March 12, 2011, at approximately 02:00 p.m. HST.

In the United States, the USGS and other seismologists are using data gained from Tohoku to better understand and update information on hazards along the Alaska-Aleutian and the Cascadia Subduction Zones, which slant beneath and can affect Alaska, British Columbia, Washington, Oregon, and Northern California. According to Brocher, the Tohoku earthquake had similar characteristics to those that might be expected of giant earthquakes in these subduction zones, which are the points where one tectonic plate moves under another.

Insights gained from the Tohoku earthquake are leading scientists to re-evaluate the way they’ve assumed many other major faults are segmented. This may end up altering some hazard analyses for the West Coast, and will contribute to improved scenario modeling, building code development, and public warnings about tsunami threats.

Moving Forward: The Work Continues in the United States

This 2008 USGS National Seismic Hazard Map shows projected earthquake intensity across the United States, including Alaska, Hawaii, Puerto Rico and the U.S. Virgin Islands. . Information from these maps is used in building codes, insurance rate structures, risk assessments, and other public policy.

As part of the multi-agency National Earthquake Hazards Reduction ProgramtheUSGS Earthquake Hazards Program has the lead Federal responsibility to notify the public when earthquakes happen in order to enhance public safety and reduce losses through effective forecasts based on the best possible scientific information.

The USGS also monitors seismic activity throughout the Nation in a constant effort to understand what causes shaking, where it will occur, and how it will impact society.

We cannot predict earthquakes, and we cannot prevent them, but we can arm ourselves with information that helps us prepare for them and mitigate damage. As Ross Stein, a USGS geophysicist, said, “Earthquakes are part of our past. They’re part of our future. We will try our best, knowing what we are up against.”

Learn more about USGS research on earthquake hazards.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. The gas burst in 1986 from the 200-meter deep Lake Nyos was so violent that water washed over the 80-meter high promontory in the foreground.

In 1986 Lake Nyos, in the volcanic region of Cameroon, suddenly released a cloud of carbon dioxide into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages.

The cause was a phenomenon later named “exploding lakes,” a hazard scientists hadn’t even known existed before the 1986 tragedy. But since then, to prevent Lake Nyos from exploding again, an international team of scientists and engineers has developed and implemented a program to artificially remove gas from the lake through piping.

USGS scientists initially advised on the project and have long monitored gas levels in the lake to determine whether this removal has been successful. This winter, USGS again joins a team traveling back to Cameroon to upgrade and re-install the monitoring devices. They’ll also update devices monitoring gas levels in nearby Lake Monoun, another exploding lake, where CO₂ has now been completely removed as part of the same project.

Although most of us may not realize it, volcanoes release more than 100 million tons of CO₂ into the atmosphere each year. (For most of the Earth’s history, volcano emissions were the primary source of CO₂ to the atmosphere; now emissions are estimated to be about 30 billion tons per year, with 100 million tons from volcanoes.) Usually the gas released during an eruption is harmless because it is rapidly diluted to low concentrations. However, sometimes the gas can get trapped underground, where it cools and becomes pressurized. If an earthquake or other disturbance later breaks the seal on this trapped gas, a dangerous, large cloud of cold, dense CO₂gas can be released in a very short period.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. A small CO2 cloud from Lake Monoun killed 37 people in 1984.

Cameroon’s exploding lakes are a unique example of this phenomenon, where CO₂ is trapped in the bottom water of deep volcanic craters. The gas stays at the bottom of the lake, held down by the pressure of the overlying water. But eventually, CO₂ gas can start to bubble up to the top of the lake, which reduces the water pressure that usually holds the gas down. When this happens, the gas from the bottom of the lake can vent with exploding force, creating a suffocating cloud that can kill people and animals in low-lying areas.

In 1986 scientists from all over the world, including USGS scientists, traveled to Cameroon to study the disasters. Over the following years, they helped establish a plan to prevent CO₂ from ever again harming the people and livestock in the surrounding villages. Beginning in 2001, a French engineering firm installed pipes that reached the very bottom of the lakes. Pumps initially push some of the lower water upward, releasing water pressure and allowing CO₂ gas bubbles to form. Once bubbles form, the gas naturally flows up and out of the pipe at a controlled rate.

This technique has successfully resulted in the complete degassing of Cameroon’s Lake Monoun, which now poses no risk of gas release. Much of the gas in Lake Nyos has been removed as well, but degassing will continue for several more years before the CO₂ is completely gone.

The USGS continues to monitor water conditions at these two lakes. The probes that measure the dissolved gas pressure are built at USGS, and are permanently installed in the lakes. After a decade of use, the most recent probes now need to be replaced.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows a pipe top and raft at Lake Nyos. The self-driven fountain (inset) can reach a height of 150 feet above the lake surface while dissipating carbon dioxide.

These probes allow the USGS and other scientists to understand the natural recharge rate of gas to Lake Monoun, which will reveal the number of years required for gas to build back up to dangerous levels. Also, the probes help scientists track the build-up of methane, another potentially dangerous gas and a byproduct of the degassing. (When the water is piped up, nutrient-rich bottom waters settle on the surface and boost algal growth, resulting in a larger supply of organic material that eventually settles back to the bottom of the lake and produces methane.)

While exploding lakes in Cameroon are unique, volcanic CO₂ poses problems in some areas of the U.S., as well. In fact, in 1994, USGS researchers discovered that large volumes of CO₂ were seeping from beneath Mammoth Mountain, a young volcano in the Long Valley area of California. The seepage was triggered by a persistent swarm of earthquakes, and killed more than 100 acres of trees. The CO₂also forced the U.S. Forest Service to close the area to camping. The USGS continues to monitor this area, where earthquakes and gas seepage remain a concern.

In 1986, Lake Nyos, in the volcanic region of Cameroon, released a cloud of CO2 into the atmosphere, killing 1,700 people and 3,500 livestock in nearby towns and villages. Since then, engineers have been artificially removing the gas from the lake through piping. This photo shows the Lake Nyos pipe in operation. The 200-meter-long pipe is suspended from the raft and allows gas-rich water from the lake bottom to vent to the surface, where the CO2 dissipates into the atmosphere at a controlled rate. The shed on the control raft is about 6 feet high and the fountain is about 120 feet high. There are no pumps involved because the CO2 drives the fountain, just like a shaken bottle of champagne.

Every year in the U.S. and around the world, natural hazards cost lives and billions of dollars in damage. The USGS provides policymakers and the public with a clear understanding of natural hazards and their potential threats to society, and assists with developing smart, cost-effective strategies for achieving preparedness and resilience. The CO₂ removal in Cameroon and monitoring near Mammoth Mountain both save lives and underscore the value of sound science in mitigating natural disasters.

Bill Evans is the USGS scientist traveling to Cameroon for this work, which is part of the USGS National Research Program. NRP researchers study the flow and chemistry of water in the environment, and the techniques they develop can be applied in many fields, including in this case, the mitigation of natural hazards.

For more information, contact Kara Capelli.

August 23, 2011 USGS Community Internet Intensity Map

Tuesday, August 23, 2011 at 01:51 PM a 5.8 Earthquake occurred 38 miles outside of Richmond, VA.
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Let us know, Did You Feel It?

Portable Seismometers:

Over the next few days, the USGS will be deploying portable seismometers around northern Virginia in order to better characterize and monitor all aftershock activity and to better define the fault zone from which Tuesday’s earthquake originated.