Combining seismic arrays to image the high-frequency characteristics of large earthquakes



This study investigates the source properties of the 2007 inline image 8.0 Pisco, Peru, 2007 inline image 8.4 and 7.9 Mentawai Islands, Indonesia, 2009 inline image 8.1 Samoa Islands and 2010 inline image 8.8 Maule, Chile, earthquakes using a backprojection technique that utilizes data from multiple seismic arrays. Combining seismic arrays increases azimuth and distance coverage and improves lateral resolution. The four subduction interface events show rupture propagation towards the bottom of the seismogenic zone. In addition, all of the earthquakes show evidence of multiple rupture segments with varying rupture speeds and directions. Relating these segments to the specific features of the subduction zones (e.g. interseismic coupling) suggests that asperity sizes may be controlled by subtle features of the subducted slab.