19 April 2018 – Seminar

When: 16:00 on Thursday, 19th April 2018
Where: DIAS, Geophysics Section, 5 Merrion Square, Dublin 2, (library)

Speaker: Andrew Schaeffer (Department of Earth and Environmental Sciences, University of Ottawa, Canada)
Title: Imaging the locked to slow slip zone in Cascadia: combining on-shore seismic data with OBS infrastructure to illuminate the seismic-aseismic transition.

Abstract:

At subduction zones, the deep seismogenic transition from a frictionally locked to steady sliding interface is thought to primarily reflect changes in rheology and fluid pressure, and is generally located offshore. The development of fluid pressures within a seismic low-velocity layer (LVL) remains poorly constrained due to the scarcity of dense, continuous onshore-offshore broadband seismic arrays. I present recent results imaging the subducting Juan de Fuca oceanic plate in northern Cascadia using onshore and OBS teleseismic data and find that the signature of the LVL does not extend into the locked zone. In the second part of my talk, I highlight the salient features of the recently funded pan-Canadian OBS Instrument Pool, the National Facility for Seismic Imaging (NFSI), and emphasize the impact this new facility will have on our understanding of fundamental tectonic processes spanning the continent.