The June 23, 2001 Peru earthquake and the southern Peru subduction zone

The plate boundary between the South American and Nazca plate along the south-central Peru coast has been the site of large destructive earthquakes for many centuries, including the June 23, 2001 (M-W=8.4) event. This underthrusting event has a fault area of 320 km by 100 km based on relocated aftershocks during the first three weeks following the mainshock. Modeling of the teleseismic broadband P waves of the 2001 Peru earthquake indicates two pulses of moment release with the larger second pulse located 130 km southeast of the mainshock initiation, indicating a unilateral rupture to the southeast. Based on intensity and tsunami reports, previous earthquakes in 1868 and 1604 were larger than the 2001 earthquake, while an event in 1784 was smaller. This provides further evidence that the size of earthquakes along the Peru coast has changed between successive earthquake cycles.