China Quakes Give U.S. Temblors Pause
Unlike the myth about lightning, earthquakes in the center of a landmass seem to never strike the same place twice. University of Missouri, Columbia researcher, Mian Liu, observed the unpredictable nature of quakes by examining the 2,000 year recorded history of earthquakes in north China.
Liu believes that his observation in China could hold a warning for the central United States.
Nearly a two centuries ago, the Mississippi River flowed backwards after a massive earthquake shook southern Missouri on February 7, 1812.
The series of quakes that rocked the New Madrid area from 1811 to 1812 weren’t the first quakes to strike the area and many scientists doubt they will be the last. But recent research by Liu and his colleagues suggests seismologists should look beyond the New Madrid fault.
“In North China, where large earthquakes occur relatively frequently, not a single one repeated on the same fault segment in the past two thousand years,” Liu said in a University of Missouri press release.
“So we need to look at the ‘big picture’ of interacting faults, rather than focusing only on the faults where large earthquakes occurred in the recent past.”
Southern Missouri experienced at least two other major shake-ups in the past 2,000 years between 800 and 1000 AD, according to a 1996 paper by researchers at the Center for Earthquake Research and Information at the University of Memphis, Tennessee. Another pair of quakes may have shook the areas near what is now Marked Tree and Blytheville, Arkansas, between 1200 and 1400 AD.
“This led scientists to believe that more were on the way,” said co-author Seth Stein of Northwestern University in a press release.
“However, high-precision Global Positioning System measurements in the past two decades have found no significant strain in the New Madrid area. The China results imply that the major earthquakes at New Madrid may be ending, as the pressure will eventually shift to another fault,” said Stein.
While this study suggests that the location of mid-continent earthquakes may be difficult to predict, the researchers are hopeful that the results will help them understand the quakes.
Mid-landmass quakes affect the central and eastern United States, northwestern Europe, and Australia.
The results were published in the journal Lithosphere.
IMAGE 1: 2008 Chinese earthquake-damaged road in Dujiangyan, Sichuan (Wikimedia Commons)
IMAGE 2: Earthquakes recorded in the New Madrid seismic zone since 1974. (USGS, Wikimedia Commons)