New Madrid Fault “Shutdown” Theory Challenged

March 16, 2009

An expert on seismic activity at the University of Illinois says he doesn't buy into a recent theory that the New Madrid Seismic Zone could be 'shutting down.'

Professors from Purdue and Northwestern universities have used GPS technology to measure surface movement in the region, which is now at less than point-two millimeters a year. The researchers say the slower the ground moves, the longer it takes for the next earthquake. The last massive ones -- three of them -- occurred in the New Madrid in 1811 and 1812.

But the Director of the UI's Mid-America Earthquake Center says those readings don't mean much since we don't understand how the mechanism is happening. Amr Elnashai also says these measurements shouldn't apply to a fault line unlike any other worldwide. He questions the definition of "closing down," saying there's no evidence of other earthquake faults that have closed down.

Elnashai says the latest theory also ignores the work of the New Madrid researchers with the University of Memphis and US Geological Survey. He says scores of scientists have determined that soil in the seismic zone has liquefied as a result of quakes that occurred well before the 1800s, and could lead to more quake activity.

Elnashai says there could be a million other explanations behind slow fault motion... and that two scientists shouldn't put the extensive research of many others and safety of eight states into jeopardy.

Story source: AP