SEAOSC Safer Cities Reconnaissance Team: Building Performance Observations and Community Resilience Assessment following the M7.1, September 19, 2017 Central Mexico Earthquake

摘要

The 2017 Central Mexico (Puebla) earthquake struck on the afternoon of the 32nd anniversary of the Mw 8.0 1985 Mexico City earthquake. At Mw7.1, the 2017 earthquake released an order of magnitude lower energy than the 1985 event, but the epicenter was located closer to Mexico City; the 2017 epicenter was located approximately 120km southeast of Mexico City, while the 1985 event was centered approximately 370km south-west of Mexico City. As such, the 2017 event created ground motions with characteristics that differed significantly from those recorded during the 1985 event. In response to the September 19, 2017 event, the Structural Engineers Association of Southern California (SEAOSC) assembled a team of structural engineers and one geotechnical engineer to travel to Mexico City as part of the Safer Cities Advisory Program. The objectives of the SEAOSC Safer Cities Reconnaissance Team (SCRT) were to 1) survey building damage and identify lessons applicable to the inventory of California construction, 2) assess community resilience, and understand how local jurisdictions were interacting and communicating with the affected communities, and 3) record building damage using 360-degree cameras, for the purpose of future earthquake response training. The SCRT traveled to Mexico City, and to the smaller rural town of Jojutla in the state of Morelos, closer to the epicenter of the earthquake. These two cities represented two extremes in terms of building construction and community resilience efforts. While significant structural damage was located in "pockets" throughout Mexico City, the damage in Jojutla was far more widespread. This paper provides a summary of the observed performance of residential and commercial construction, including retrofitted buildings in both urban and rural areas. Interviews with building officials and members of the local community are also discussed, outlining some of the logistics the local jurisdiction faced in the days and weeks after the earthquake, and the recovery efforts of affected communities.