Effects of the September 2017 Earthquakes on Mexican Dams

Abstract

On September 7 and 19, 2017 two earthquakes of magnitudes 8.2 and 7.1, respectively, and their aftershocks occurred in Mexico in regions where more than 750 dams operate, from which around 154 were exposed. Most of the reservoirs were full at the time of the earthquakes, and therefore subject to unprecedented intense dynamic loads. A description of the earthquakes and an account of the affected dams is provided; some of the dams presented cracking in various parts, especially on the crests, due to large peak ground acceleration (PGA) values. Previous studies related to dam safety are briefly described, together with a comparison of current dam design criteria against dam design practices in Mexico at the time the dams were built. Safety revision protocols as well as design criteria and stability estimation procedures are also revised. Then, inspection actions are taken, and damages and seismic evaluation after the events are presented, as well as a discussion on seismic-induced dam crest settlement estimation. Finally, conclusions and recommendations regarding remedial actions are presented.