New Madrid Earthquakes Remain a Mystery

No one knows what caused a series of major earthquakes centered near New Madrid, Missouri, and felt in much of the eastern United States 200 years ago, according to geologists at the “It’s Your Fault” conference, University of Missouri, February 18, 2012.

I attended to hear whether any new information would affect my Thunder Beneath My Feet manuscript (nothing did) and when to expect the next big ones (no one knows).

Experts can tell big earthquakes occurred in the state’s southeast corner about 1450 and 900 and at similar intervals for 5,000 or so years. They don’t know whether other catastrophic quakes are coming in 300 years, 50 years, or never. Some theorize that the few modest quakes and countless tremors since 1812 are aftershocks that will eventually end.

Professor Eric Sandoval, a member of the Missouri Seismic Safety Commission, called the New Madrid seismic zone one of the most difficult to understand on the planet. Located in the middle of—rather than on the boundary of—a tectonic plate, this zone doesn’t fit the models that apply in most of the world, including California.

New Madrid resembles a seismic zone in northern China, said Professor Mian Liu. Models indicate low hazard, but quakes have killed hundreds of thousands. He emphasized that over a few centuries quakes in such zones may occur in different locations. Why? Nobody knows for sure. Recorded history deals with only a fraction of earthquakes, and much of what happens deep beneath the earth’s surface remains a mystery.

I live about 300 miles from the New Madrid earthquake epicenter, close enough for a 7.+ quake to bring down chimneys and spires. Until geologists find more clues to the mystery, I won’t know whether my quake insurance makes sense.