A study of the 2006 and 2007 earthquake sequence of Pisco, Peru, with InSAR and teleseismic data

We combine interferometric synthetic aperture radar (InSAR) and teleseismic body waves to study the largest earthquake (M(w) 8.1) in a sequence of events on the subduction megathrust near Pisco, Peru. Our analysis includes some of the first InSAR data from the ALOS satellite and wide swath data from the Envisat satellite. The teleseismic data indicate the slip maximum occurred 60 90 seconds after the mainshock started. The InSAR data constrain the main slip patch to be about 70 km from the hypocenter, suggesting an extremely low rupture velocity (<1.5 km/s) or long slip rise time. No large earthquake has occurred in the 2007 rupture area since at least 1746 and possibly 1687, suggesting significant aseismic deformation in the area. The slip deficit apparently cannot be filled with rapid after-slip. In addition, the area where the Nazca Ridge is subducting appears to be either a seismic gap or a persistent area of aseismic slip.