The M = 8.1 Chiapas and the M = 7.1 Puebla earthquakes occurred in the bending part of the subducting Cocos plate 11 days and ~600 km apart, a range that puts them well outside the typical aftershock zone. We find this to be a relatively common occurrence in Mexico, with 14% of M > 7.0 earthquakes since 1900 striking more than 300 km apart and within a 2 week interval, not different from a randomized catalog. We calculate the triggering potential caused by crustal stress redistribution from large subduction earthquakes over the last 40 years. There is no evidence that static stress transfer or dynamic triggering from the 8 September Chiapas earthquake promoted the 19 September earthquake. Both recent earthquakes were promoted by past thrust events instead, including delayed afterslip from the 2012 M = 7.5 Oaxaca earthquake. A repeated pattern of shallow thrust events promoting deep intraslab earthquakes is observed over the past 40 years.
|Title||Testing earthquake links in Mexico from 1978 up to the 2017 M=8.1 Chiapas and M=7.1 Puebla shocks|
|Authors||Margarita Segou, Thomas E. Parsons|
|Publication Subtype||Journal Article|
|Series Title||Geophysical Research Letters|
|Record Source||USGS Publications Warehouse|
|USGS Organization||Pacific Coastal and Marine Science Center|