The February 27, 2010 Maule, Chile earthquake (Mw = 8.8) is the fifth largest earthquake to occur since 1900. Its effects were felt along 600 km of the central Chile coast. Initial field observations suggest that tectonic displacement of the hanging wall produced both uplift of over 2 m and subsidence of up to 1 m in coastal regions. The tsunami initiated by the rupture devastated parts of the coast and killed hundreds of people. Strong shaking lasted for over a minute in some areas, and widespread damage occurred in some cities. A large number of significant aftershocks contributed additional damage to an already fragile infrastructure.

This major earthquake was the subject of several post-earthquake reconnaissance efforts. This report presents the observations of the NSF-sponsored Geo-engineering Extreme Events Reconnaissance (GEER) team. GEER team members included engineers, geologists, and scientists from Chile and the United States. The GEER team worked closely with other reconnaissance teams, including EERI, USGS, NIST, FEMA, TOSG, PEER, and ASCE, amongst others, to document the geotechnical effects of this significant event so that our understanding of earthquakes can be improved and we may turn disasters such as this one into knowledge for advancing societal resilience.