At 12:38 yesterday morning, St. Louis felt the trembles of 4.0-magnitude earthquake, one of at least five small aftershocks of Friday’s earthquake.
According to the U.S Geological Survey National Earthquake Information Center, yesterday’s earthquake occurred near Mount Carmel, Illinois, 131 miles from St. Louis.
Xiaodong Song, associate professor in the department of geology at the University of Illinois at Urbana-Champaign said that while the original earthquake was moderate, in the Midwest earthquakes are typically more largely felt than in other areas.
“This earthquake was felt far and wide in the Midwest because earthquake waves (seismic waves) attenuate slower than, say, in California. The rock layers here are old and transmit seismic waves more efficiently. Rock layers in the West Coast are younger and absorb seismic waves better,” Song wrote in an e-mail to Student Life.
Song noted that earthquakes are rare occurrences in the Midwest, but that the largest earthquake ever recorded in North America was of 8.0-magnitude in 1811 and located on the New Madrid fault line.
While the next earthquake in this area cannot be predicted, Song said the Midwest and St. Louis should be prepared.
“We don’t know when a bigger one will come in this area. But it will affect St. Louis and much of the Midwest,” Song wrote. “The fact that the New Madrid/Wabash Seismic Zone is not very active does not mean we are not subject to seismic risks.”