South Carolina seismic activity not uncommon

A recent small earthquake in the Lowcountry shook houses in the Summerville area. College of Charleston Geology professor Dr. Erin Beutel (byoo-tel), said the tremor that occurred last Wednesday registered about a two on the Richter scale. Beutel says a tremor of that magnitude would feel like an 18 wheel truck passing by your home rattling your coffee cup. Beutel says the Summerville area and other parts of the state typically gets several tremors a year.”We have averages just like with floods that happen sometimes more years than not. We have two to seven reported felt earthquakes {annually). That doesn’t mean that there are not more that are happening or people felt and didn’t report. We are talking about just the ones that are reported.”
Beutel says a 2.5 quake was recorded in the Summerville area in January. Beutel Says South Carolina experiences quite a few seismic episodes annually, but it does not compare with the tremendous amount of seismic activity that occurs in states like California, Washington, and Alaska.
Beutel says the strongest earthquake in the state occurred in and around the Charleston area on August 31, 1886, and is considered in historical times as the greatest earthquake on the U.S. east coast. Beutel says the earthquake is estimated to have been around a magnitude seven. Beutel says since their was no seismometers around at the time the magnitude was estimated using reports of the damages that occurred at the time. Beutel says scientists are studying the geological history of a region by digging trenches and studying how the earth well below the surface has been affected by a process known as liquefaction.
“Liquefaction is where the ground saturated in water basically turns into a slurry and you only have that with magnitude six and above earthquakes. You see that in a geologic record (of an area) about every 500 years. We see on average, once again we get nervous as scientists because mother nature doesn’t like to be predictable, we see large earthquakes of that size (the 1886 quake) around every 500 years.”
Beutel says according to historical documentation, the 1886 quake was felt over a vast area from Canada to the Gulf of Mexico.
Beutel says the study of a region’s seismic history can help architects determine how buildings are constructed to withstand frequent seismic activity. Beutel says the information also helps in determining where nuclear facilities are located.
“I believe that nuclear facilities have a certain size earthquake that they have to be able to withstand and they try to locate those as far away from active areas as possible.”