Seismic Pulses before the February 27, 2010 M = 8.8 Chile Earthquake

Abstract—We study the records of ground motion vertical velocity in the vicinity of broadband seismic stations on the west coast of South America and in the adjacent region of the Pacific Ocean, where the M_w 8.8 earthquake occurred on February 27, 2010. Starting from 2009, asymmetric seismic pulses lasting several hundred seconds have been detected in records of some stations. These pulses occurred under quiet weather conditions and low geomagnetic activity. It is believed that the earthquake was preceded by tectonic movements in the oceanic and continental lithosphere.