Post earthquake slow slip following the 2012 Nicoya Earthquake
Tuesday, 23 February 2016: 3:45 PM
Nicholas K Voss1, Timothy H Dixon1, Zhen Liu2, Rocco Malservisi1, Susan Y Schwartz3, Marino Protti4 and Victor Gonzalez4, (1)University of South Florida Tampa, Tampa, FL, United States, (2)Jet Propulsion Laboratory, Pasadena, CA, United States, (3)University of California-Santa Cruz, Santa Cruz, CA, United States, (4)Observatorio Vulcanológico y Sismológico de Costa Rica, Heredia, Costa Rica
Abstract:
Slow Slip Events (SSE) beneath the Nicoya Peninsula in Costa Rica have been occurring regularly (recurrence interval ~21 months) since the installation of continuous GPS stations in 2002. This recurrence interval continues unchanged past the September 5th, 2012 Nicoya M 7.6. Following the earthquake, an SSE occurred ‘right on time’ in February of 2014, 20 months after the preceding SSE, despite ongoing postseismic deformation. This Mw=7.0 event is located downdip of the coseismic slip area, at a depth between 25 and 45 km, coincident with the location of prior deep SSEs. Shallow slow slip does not occur during the 2014 event, possibly indicating a change induced by the earthquake, since pre-earthquake SSEs generally included shallow slip. Further, a new event appears to have begun in the fall of 2015 and is ongoing as of submission of this abstract. It appears that the recurrence of SSEs in the Nicoya was unaltered by the 2012 earthquake. We explore the behavior of these post earthquake SSEs using Mohr-Coulomb failure stress analysis and discuss their relationship with the 2012 earthquake.
