Seismologist Mario Pardo rebukes notion that Pichilemu, Chile experiencing "seismic swarm"

Friday, March 19, 2010

The Lolol church, one of the 66 churches in the O'Higgins Region. The photo shows the severe structural damage that suffered the church after the earthquakes.
Image: Diego Grez.

Mario Pardo, a geophysicist at the University of Chile, has ruled out that a "seismic swarm" exists in the coastal town of Pichilemu, about 259 kilometers from Santiago. As of last Thursday, almost 70 seisms have been registered in that zone.

Pichilemu was the epicentre of a 6.9 moment magnitude earthquake last Thursday that resulted in two aftershocks of magnitude greater than six.

"These are aftershocks associated to that earthquake. They are not more than a technicality: a seismic swarm doesn't correspond to an aftershock sequence that will last in some time", he explained.

The seismologist, in an interview with Cooperativa Radio, explained that the situation in Pichilemu occurs generally in areas where the aftershocks "can't be differentiated from a main seism, where they have very similar magnitudes, and when they take some time to disappear".

Adobe houses and historic buildings sustained the most damaged in the region: in fact, Monsignor Alejandro Goic said that only 2 of the 66 traditional catholic buildings in the region were not damaged. Damages to Catholic churches solely in the O'Higgins Region were estimated at almost 20 billion Chilean pesos (US$ 38 million). "It's stratospheric, a number that surpasses us absolutely," Goic said.