The Pisco (Peru) earthquake of 15 August 2007

Abstract

The Mw 8.0 Pisco earthquake struck at 6.40pm local time with an epicentre offshore about 150 km south of Lima. At least 519 people were killed, and over 1,300 injured. Over 38,000 homes were destroyed and more than 100,000 were made homeless. 14 hospitals were destroyed and many other facilities damaged. The city of Pisco was worst affected with serious damage to the majority of adobe buildings. Other cities and towns nearby suffered similar damage to a lesser extent, depending on the distance from the epicentre. The capital Lima was not seriously affected, although there was some minor damage to buildings.
 Strong ground motions were felt for over two minutes. In this subduction earthquake a tsunami was generated and affected tens of kilometres of coast.
 The New Zealand Society for Earthquake Engineering Society (NZSEE) sent a 6-person reconnaissance team to Peru. The team spent three days in Lima meeting with key authorities and four days in the field observing some of the earthquake-affected area. This report describes the team’s observations and comments on the implications for earthquake engineering practice.
 Highlights of the event in the eyes of the team were:
 
 The long duration of the event – over 2 minutes of strong shaking
 The unique geotechnical context – no rainfall and sandy soils
 Significant liquefaction damage to roads and buildings
 Poor performance of adobe construction
 Generally good performance of reinforced concrete brick infill – but there were major collapses.
 Good performance of some unreinforced masonry buildings
 Widespread use of shear walls in major buildings in Lima
 Engineered structures generally performed well
 Damage to parts of Pan American Highway due to liquefaction
 Minimal damage to a major steel mill, designed to international standards
 Collapse and/or overload of telecom systems for up to four hours following the event, isolating Pisco and Ica
 Water and waste water systems and storage were seriously affected in Pisco, and significantly in Ica
 Port St Martin, serving Pisco, was seriously damaged but functional
 Coordination of overseas / international aid needs careful consideration as part of response planning.
 Management of response resources is critical.
 There were significant tsunami effects which were variable in height up to 10 metres.
 Relatively minor damage to architectural finishes and building services can render hospitals non-functional.
 Survival of industrial facilities was important in reducing social impact by saving jobs.
 The best of Peruvian earthquake engineering is international standard.
 The development of earthquake-resistant standards in schools over the last three decades has paid dividends with modern designs performing well.