Regional landslide hazard assessment from seismically induced displacements in Monterrey Metropolitan area, Northeastern Mexico

The first regional seismic landslide hazard assessment for Northeastern Mexico is presented. Regional maps predicting the expected areal limits for potential earthquake-induced landslides in terms of coseismic displacements for the 2010 San Pedro earthquake (M 4.0) and two postulated M 5.5 and M 6.5 scenario earthquakes are shown. Permanent displacements were obtained from a global empirical regression based on a critical acceleration ratio (a_c/PGA) estimation. Results for the M 4.0 San Pedro event show low cumulative displacements concentrated around the epicentral zone. For this event, occurrence of a few small landslides as disrupted slides and falls were likely. For M 5.5 and M 6.5 scenarios the coseismic displacements depict a high potential for widespread and complex slope failures mainly in the Sierra Madre Oriental hilly areas, although foothills inside the Monterrey Metropolitan Area would be affected. The worst scenario we have postulated is a M 6.5 earthquake during the hurricane season. Hypothetical full-saturated and strong seismic shaking conditions would trigger several rock and soil avalanches as well as other complex landslides. Related damage for this event would be very catastrophic to civil infrastructure and substantial injuries and loss of life are expected mainly in the southwestern portion of the Monterrey Metropolitan Area. Results constitute a useful tool in order to mitigate potential earthquake-induced damage related to regional slope failures.