A Year After the 2011 Virginia Earthquake: Will Shaking Continue?

A Year After the 2011 Virginia Earthquake: Will Shaking Continue

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Melanie Gade:  Hello, and welcome to USGS CoreCast. I'm your host, Melanie Gade. Today I am here with U.S. Geological Survey geologist Doctor Mike Blanpied. Doctor Blanpied has been very involved in USGS efforts and response to the August 23, 2011 Virginia earthquake. This magnitude 5.8 earthquake which occurred near Mineral, Virginia, was among the largest to ever occur on the Eastern Seaboard in the past 400 years. The earthquake was felt on the East Coast from Northern Florida to Ontario, Canada, and as far west as Mississippi.

Today we are going to discuss whether shaking of this kind could happen again in the area in the near future. 

So Mike, my first question to you is: Were people surprised by the earthquake? Do you think they should have been?

Dr. Mike Blanpied:  Well, we don't feel earthquakes in the Eastern U.S. very often, and for most people in the east this was the first earthquake they ever felt. Many people were not even aware that it was an earthquake. They just knew that something was shaking. Scientists were not surprised that this earthquake happened because we know that such things have happened in the past and will happen in the future. There was an earthquake of similar size in Southwest Virginia in the late 1800s.

In fact, Central Virginia had been designated as a seismic zone on USGS seismic hazard maps because it has a frequent occurrence of smaller magnitude earthquakes. We had recognized the possibility that this earthquake would happen, but of course as with any earthquake we can only say that it's likely and we can never say exactly when it's going to occur.

Melanie:  My follow up question then would be, what is the likelihood that a similar earthquake could happen again in this area in the near future?

Mike:  Well, there are many faults that are available for making earthquakes. The fact that we just had one meant that there was an aftershock sequence, of course. So it was very likely that we had aftershocks afterwards. That likelihood is dwindling away. It's still possible we'll have some big aftershocks, but not as likely as it was earlier on. And overall in the region, the likelihood has not changed. There's a small, but not a zero, chance that we'll have a large and damaging earthquake pretty much anywhere in the eastern U.S. We hope that when the next one occurs, whenever that is, that, like this one, it's located well away from urban areas.

Melanie:   Mike, I have just one final question for you: In an earthquake, can you tell me, what can people do to stay safe?

Mike:  For many people in the East, this was their first earthquake and people really were taken off guard and people reacted, not even knowing it was an earthquake in some cases. The best thing to do if you're indoors is to drop down low, get underneath something, and hang on. Drop, cover, and hold on. If you are outdoors during an earthquake, move away from buildings and away from anything that might fall. What you don't want to do during and earthquake is start out indoors and then run outside. Because, the most likely place to get hurt is just outside of a building, which is exactly where you'll be during the shaking when things are falling off the building. So if you're indoors, stay put. Protect yourself. If you're outdoors, move away from the building.

The earthquake is only going to last for a few seconds so hang on, ride it out, and then move to safety afterwards.

Melanie:  Thank you, Mike. This concludes this episode of USGS CoreCast. Visit Earthquake.USGS.gov for more information about the USGS Earthquake Hazards Program. And don't forget to follow the USGS on Twitter at Twitter.com/USGS or visit our other social media channels at USGS.gov/socialmedia. CoreCast is a product of the U.S. Geological Survey, Department of the Interior. I'm Melanie Gade, thanks for listening.