Peru Earthquake

First Posting | Summary
Posting Date: October 20, 2006, 12:00:00 PM

A strong earthquake struck off the coast of Peru on Friday, October 20, 2006, at 5:48 a.m. local time, 10:48 a.m. UTC. The USGS has estimated the earthquake’s magnitude at 6.5. The epicenter was located about 95 miles south-southeast of the Peruvian capital of Lima at an estimated depth of 20.6 miles. No injuries or major damage have been reported as yet, though there have been reports of minor damage to houses near the epicentral region. The Pacific Tsunami Warning Center did not issue a basin-wide tsunami alert, but did advise that a local tsunami could occur on the coast within 100 km of the epicenter. Peru’s earthquake history stretches back some 450 years. The Andes Mountains and the offshore Peru-Chile trench are significant breeding grounds for strong quakes. In June 2001, a magnitude 8.4 quake destroyed more than 17,500 homes, damaged 35,500, and killed 75 people—26 from a tsunami that reached up to 1 km inland in some locations. The most destructive earthquake in Peru in recent memory occurred in May 1970. This magnitude 7.9 temblor caused significant structural damage (estimated at the time near $350 million) and loss of life (upward of 70,000 by some estimates), mostly from landslides and building collapses. The source mechanism of this earthquake suggests a subduction zone event. Historically, central Peru has experienced a number of large destructive subduction-related earthquakes. Peru is located on the well-defined seismic belt of the Peru-Chile arc. The region is characterized by high seismic activity and a deep trench. The Nazca plate subducts under the overriding South American plate with an approximate convergence rate of 7.8cm/year. This particular earthquake occurred within the part of the subduction zone with notably flat characteristics. The Nazca plate subducts beneath the South America plate with about 30 degrees dipping angle to about the depth of 100 km, where it flattens and runs sub-horizontally for several hundred kilometers before dipping steeply into the upper mantle. The most recent rupture of the segment of the subduction zone where the earthquake happened was in 1974, generating a magnitude 8.0 earthquake. Two notable historic events in this region occurred in 1746 (magnitude 8.6-9.05) and 1687 (magnitude 8.4-8.8). These earthquakes ruptured the Nazca plate north and south of the epicentral location of this earthquake. In the May 2006 release of CATRADER, Peru was added to the AIR Earthquake Model for Mexico and South America. Using the latest available seismic information about today’s event, model results indicate that based on the location and focal depth of this earthquake, insured losses will be minimal.

First Posting | Downloads
Posting Date: October 20, 2006, 12:00:00 PM