Earthquakes: Frequently Asked Questions

• Where can I find current earthquake lists and maps?
• Can I get on a list to receive an e-mail message when there is an earthquake?
• How can I report an earthquake experience or related observation?
• Where can I search an earthquake catalog?
• Where can I see current or past seismograms?

• Can you predict earthquakes?
• Can animals predict earthquakes?
• Can you prevent large earthquakes by making lots of small ones, or by "lubricating" the fault with water?
• Can some people sense that an earthquake is about to happen?
• Is there earthquake weather?
• Are there more earthquakes in the morning/in the evening/at a certain time of the month?
• Can the position of the moon or the planets affect seismicity?
• Can the ground open up during an earthquake?
• Will California eventually fall off into the ocean?
• Why are we having so many earthquakes? Has earthquake activity been increasing?
• Do earthquakes cause volcanoes?

• What is an earthquake and what causes them to happen?
• Can we cause earthquakes? Is there any way to prevent earthquakes?
• Can earthquakes be predicted?
• There have been alot of earthquakes lately. Does that mean a big one is coming?
  There have not been many earthquakes lately. Does that mean a big one is coming?
• What do we know about the interior of the Earth?
• What is plate tectonics?
• What is a fault and what are the different types?
• At what depth do earthquakes occur?
• What is "surface rupture" in an earthquake?
• What is the relationship between faults and earthquakes?
• How do we know a fault exists?
• Where can I go to see the/a fault?
• What does an earthquake feel like?
• Foreshocks, Aftershocks - What's the difference?
• Two earthquakes occurred on the same day. Are they related?
• Where can I get a fault map?
• Where can I get a fault maps with roads and towns?
• Where can I find information about faults in my area?
• How can I find out about earthquakes in my area?
• Where can I find information about volcanoes?
• How can I find out about tsunamis?

• Where can I buy a Richter scale?
• How are earthquakes recorded? How are earthquakes measured? How is the magnitude of an EQ determined?
• What are the different magnitude scales, and why are there so many?
• Why are there often different magnitudes reported for the same earthquake?
• What is "moment magnitude"?
• What are the earthquake magnitude classes?
• How do you give a Richter magnitude to earthquakes that occurred prior to the scale?
• When was the first instrument that actually recorded an earthquake?
• What is a P wave? An S wave?
• What was the duration of the earthquake?
• What does an earthquake look like?
• How do seismologists locate an earthquake?
• What is intensity? What is the Modified Mercalli Intensity Scale?
• What is the difference between intensity scales and magnitude scales?
• How much energy is released in an earthquake?
• What is acceleration, velocity, and displacement?
• What is spectral acceleration?
• What are those beachball figures?
• What are GMT and UTC (in reference to the time of an EQ)?

• What is a seismometer? What are seismographs? How do they work?
• What are seismograms? How do you read them?
• How is the movement of the seismometer converted into a seismogram?
• How can I make my own seismometer?

• What are the effects of earthquakes?
• At what magnitude does damage begin to occur in an earthquake?
• Where can I find photographs of earthquake damage?
• Why do earthquakes in other countries seem to cause more damage and casualties than earthquakes in the U.S.?
• How do you classify/measure the shaking that you feel during an earthquake? Sharp jolts versus rolling motion?
• What are isoseismal maps?
• What is liquefaction?
• Do earthquakes cause volcanoes?
• What are earthquake lights? Are they real?

• Are earthquake probabilities or forecasts the same as prediction?
• What is the probability that an earthquake will occur in the Bay Area?
• What is the probability that an earthquake will occur in the LA Area?
• What is seismic hazard and how is it determined?
• Where can I find seismic hazard maps?
• How do earthquakes affect buildings?
• How will my house hold up in an earthquake? Can the USGS send someone out to evaluate my property?
• How are engineers making bridges and buildings safer from earthquakes?
• What are the Guidelines for evaluating and mitigating seismic hazards in California?
• What is the USGS doing to mitigate and respond to earthquake hazards?
• How do I decide whether or not to get earthquake insurance?

• Where do earthquakes occur?
• What is the biggest earthquake ever?
• What is the biggest earthquake in the United States?
• Which States in the United States have the most earthquakes?
• Which State has the most damaging earthquakes?
• Which States have the smallest number of earthquakes?
• I want to move to a place that doesn't have earthquakes. Where can I go?
• How many earthquakes worldwide occur each day? Each year?
• Where I find a list of the largest earthquakes in my town?
• Where can I find a list of the most destructive earthquakes in the world?
• Where can I find a list of the largest earthquakes in the United States?
• Where can I find a list of significant damaging California earthquakes?
• Where can I find other lists of earthquakes?
• Can I do an earthquake catalog search to get my own list of earthquakes?

• What is the Comprehensive Test Ban Treaty?
• What is the role of seismology in monitoring a CTBT?
• What are the differences between explosions and earthquakes?
• Can nuclear explosions cause earthquakes?
• Can we use alot of explosives to cause small earthquakes in order to prevent having large ones?

• Washington/Oregon
• California
• Nevada
• Utah
• Central US/New Madrid
• East Coast/New England

• During an EQ should you head for the doorway?
• What emergency supplies do I need?
• How can I plan ahead for an EQ?
• What should I do during an EQ?
• Things NOT to do during an EQ?
• What can I expect in my house when an EQ occurs?
• What do you do AFTER EQ?
• What are the steps to EQ safety/awareness?

• What are some good books on earthquakes and geology?
  
• Where can I find educational materials?
  
• Where can I find other online resources on earthquakes?

Most of this information was compiled from the following sources:

• US Geological Survey, Western Region Office, Menlo Park, CA
• US Geological Survey, Eastern Region Office, Reston, VA
• US Geological Survey, NEIC, Golden, CO
• University of California, Berkeley, Seismological Laboratory - FAQ link
• US Geological Survey, National Seismic Hazards Mapping Project - FAQ link
• University of Washington Seismological Laboratory - FAQ link
• University of Nevada, Reno, Seismological Laboratory - FAQ link
• University of Utah, Seismograph Stations - FAQ link
• University of Memphis, CERI - FAQ link
• University of Arizona
• Multidisciplinary Center for Earthquake Engineering Research (MCEER) - FAQ link
• California Geological Survey