60 Second Science
Whose Fault?: North American Earthquakes
by Sharmin Shanur
The earthquake in Mexico City last Tuesday has shaken people all around the world. With hundreds of casualties and thousands of damaged buildings, it seems Californians need to prepare for the worst. However, the earthquake in Mexico was a unique situation. Unlike any highly populated city in the world, Mexico City resides over a shallow lakebed, so it’s foundation mimics jello—this means that after an earthquake occurs, the ground reverberates back and forth, causing much more damage to the city’s infrastructure. For this reason, the earthquake was especially detrimental to Mexico City.
Originally, geologists and seismologists had been watching the Guerrero Gap, a section of a fault near the coast, in hopes of preparing for an upcoming earthquake. The Guerrero Gap has not caused an earthquake for decades, and for this reason scientists believed that all the built-up pressure at the fault would cause a quake. However, the epicenter of the Mexico City earthquake was not in that gap. The earthquake emerged 35 miles below the surface from the interior mountains of Mexico City. Scientists had been watching the wrong area.
Of course, this begs the question, should we be worried about a devastating earthquake striking California? According to Julie Dutton, a geophysicist at the U.S. Geological Survey’s National Earthquake Information Center, and Professor Andrew Newman from the School of Earth and Atmospheric Sciences at Georgia Tech, there is nothing to worry about. The earthquakes in Mexico City have no connection with California’s infamous San Andreas Fault. This does not mean California will not have any earthquakes—it just means there is no correlation between the two.