November 3, 2011
Scientists studying the Aug. 23 5.8-magnitude earthquake and the subsequent aftershocks say it's possible there is a new fault line in Central Virginia.
U.S. Geological Survey (USGS) workers Mark Carter and Mike Blanpied hosted a live Twitter lecture Wednesday titled “Did You Feel It? The Virginia Earthquake of August 23, 2011.” Months after the historic quake – the strongest in Virginia in 114 years – seismologists are taking advantage of nature's lesson.
“Following an earthquake of this kind it's a unique opportunity for scientists to get a better understanding of this earthquake and its aftershocks,” said Blanpied, an associate program coordinator for the USGS Earthquake Hazards Program.
The 208 portable seismographs they have placed throughout Central Virginia have recorded more than 600 aftershocks since the original quake, although only about 40 of those have registered a 2.0 or higher on the USGS “Latest Earthquakes” map.
While all that is normal, Blanpied and Carter say what those aftershocks revealed was, well, shocking.
“The fact that we had a big earthquake was not a surprise, but the exact fault that it might have occurred on is a bit more of a mystery,” he explained.
“What we might be looking at is either a new fault or a previously undiscovered one deep within the geologic formations here,” Carter wrote.
If that's true, and the 5.8 quake occurred on a previously unknown fault, it could mean more strong earthquake in the future. The potential discovery has led USGS seismologists to do new geological mapping to determine exactly how many fault lines are under Central Virginia.
Although they cannot say when or where, scientists are positive Central Virginia will continue to feel more minor to severe aftershocks for possibly years to come.