NSFGEO-NERC: The Role of Asperities and Slow Slip in Subd. Zone Earthq. Rupture and Aftershock Sequ.: In sights from the 4/16/16 Pedernales Ecuador

In April 2016, the Pedernales Earthquake ruptured an ~ 130 km long, 100 km wide segment of the subduction zone along the coast of Ecuador in a Mw 7.8 megathrust event. Immediately after the earthquake a coordinated international rapid response effort deployed 48 broadband and intermediate period seismometers and 10 ocean bottom seismometers above the rupture zone and adjacent fault segments where large earthquakes occur on decadal time scales and slow slip events have been observed.
The seismic array is complemented by rapid response geodetic efforts and long term observations from permanent national seismic and geodetic networks in Ecuador. We will use subduction of the Nazca Plate beneath Ecuador and the Pedernales Earthquake and aftershock sequence to link along strike variations in structure and seismic properties to the distribution of slip behaviors observed (pre-, co- and post-seismic) to determine the relationship between slow slip and megathrust rupture. We will integrate analyses from a variety of broadband seismic techniques to examine the persistence of asperities for large to great earthquakes over multiple seismic cycles, the role of asperities in promoting or inhibiting rupture propagation, and the relationship between locked and creeping parts of the subduction interface.

Ecuador has a history of damaging earthquakes. Outcomes from this research will contribute to ongoing efforts to assess risk from subduction zone earthquakes in the wake of the April 16 2016 Mw 7.8 Pedernales earthquake. We are partnering with Build Change, a non-profit NGO, to develop materials to educate local communities on earthquake hazards and construction techniques to improve resiliency. This project supports research infrastructure in seismology and computation at three universities and includes education, professional development, and training for early career scientists (post-docs and graduate students) in an area where science and society overlap. Results from this research will be integrated into STEM education at both the graduate and undergraduate level. The Pedernales earthquake and aftershock sequence provides an excellent example for students to explore hazards associated with subduction zone processes, the earthquake cycle, and the integration of basic and applied research.