Staff Dispatch: Learning From the Mexico City Earthquake, by Dana Brechwald

* First in an occasional series of dispatches from MTC and ABAG staff about their experiences out in the field. From the Bay Link Blog.



On September 19, 2017, Mexico City experienced a damaging magnitude 7.1 earthquake, resulting in the deaths of 228 people and the collapse of 44 buildings. The 2017 earthquake occurred on the 35th anniversary of another deadly earthquake in the city that killed nearly 10,000 people.



Due to geological, building construction and social factors, Mexico City is highly vulnerable to earthquakes. Much of the city sits on an ancient lake bed that has been drained over the last several centuries to accommodate the city's expansion. This geology leads to significant subsidence and loose soils, which worsens ground shaking and can cause liquefaction in earthquake events.



In addition, although Mexico's current building codes are similar to those in the Bay Area, many existing buildings date back decades or centuries, before these codes were in place. Nearly 60 percent of residential buildings are self-built without permits or inspections, meaning they don't comply with any codes at all. Many of these residents are also highly vulnerable due to their social status — they often lack savings, insurance, secure jobs or even legal rights to their own homes.



For the remainder of the dispatch, visit https://blog.bayareametro.gov/posts/staff-dispatch-learning-mexico-city-earthquake