New Mexico Tech PhD student Emily Morton was selected to receive the outstanding student presentation award at the 2016 Annual Meeting of the Seismological Society of America. The meeting was held in Reno, NV, in April and had over 625 presentations. Emily's presentation can be viewed here on the members-only section of the SSA website, and her abstract can be viewed below:
Session: Multidisciplinary Studies of Earthquakes - Slow, Fast, and In Between: A Broad Range of Fault Behavior in Space and Time
CASCADIA SEISMOGENIC ZONE EARTHQUAKE DETECTION AND LOCATION
MORTON, E. A., New Mexico Tech, Socorro, NM, USA, firstname.lastname@example.org; BILEK, S. L., New Mexico Tech, Socorro, NM, USA, email@example.com; ROWE, C. A., Los Alamos National Laboratory, Los Alamos, NM, USA, firstname.lastname@example.org
The Cascadia Subduction Zone (CSZ) produces regularly observed episodic tremor and slip (ETS) behavior and geologic evidence indicates past great earthquakes have occurred along the margin. With the absence of a historically observed great earthquake, small and moderate magnitude earthquakes are needed to infer fault zone conditions, but the CSZ is notable for its dearth of such events. The seismogenic zone appears to reside primarily offshore; therefore the paucity of observed small, interplate earthquakes may arise partly from the use of only on-land seismometers, far from the earthquake sources. The Cascadia Initiative (CI) community seismic experiment includes ocean bottom seismometers (OBS) deployed directly above the presumed locked seismogenic zone, in addition to land seismometers. We use the CI dataset to search for small magnitude interplate earthquakes previously undetected by the on-land sensors.
Within the first year of CI waveforms, we select a subset of M0.1-3.7 earthquakes from existing earthquake catalogs, whose preliminary locations and depths suggest that they occurred on the plate interface. We create templates to build a subspace detector by windowing waveforms around the arrival times for these events on CI OBS and land seismometers. Our initial efforts targeted a known cluster of repeating events off the coast of central Oregon, yielding 293 unique detections. Eighty-six are well located, most of which occur in the vicinity of the targeted cluster. Here we present detections and locations for the first year of CI deployment. Ongoing efforts will include continuing detection and location along the margin during CI deployment. Future plans include source parameter analysis of events along the margin for fault zone characterization.