HR: 0800h
AN: T21A-0345    [Abstracts]
TI: Spatial and Temporal Patterns of Non-Volcanic Tremor Source Locations All Along the Cascadia Subduction Zone
AU: * Boyarko, D C
EM: boyarko4@gmail.com
AF: Miami University, 114 Shideler Hall, Oxford, OH 45056, United States
AU: Brudzinski, M R
EM: brudzimr@muohio.edu
AF: Miami University, 114 Shideler Hall, Oxford, OH 45056, United States
AB: Along the interface of a convergent plate boundary, the potential for megathrust earthquakes lay in the seismogenic zone, where the converging plates are locked and accumulating strain. Downdip from the seismogenic zone, the increasing temperatures and oceanic slab dehydration generate a transitional zone between the locked and free-slip portions of the subduction interface. Episodic Tremor and Slip (ETS), the correlation of slow slip events monitored by GPS observations and non-volcanic tremor (NVT) monitored by seismic signals, is believed to originate in this transitional zone. The processes that govern ETS and its relationship to megathrust earthquakes in space and time remain unresolved, although ETS has been proposed to impact the likelihood of megathrust earthquakes. Given the increased density of seismometers with the initial deployment of the Earthscope Transportable Array over the past 2 years, one can begin to examine the sources of NVT all along the Cascadia subduction zone in detail. We analyze NVT signals following Obara (2002) in which the cross-correlation of filtered envelope seismograms is used to define S-wave arrivals that are then converted to hypocentral locations. We apply this technique to the last ten years of seismic data collected at both short-term and long-term stations along the entire Cascadia subduction zone to determine spatial and temporal patterns in source locations. Specifically, we will address segmentation and recurrence defined by where and when ETS events start and stop, as well as hypocentral migration rates, directions and geographic variability.
DE: 7215 Earthquake source observations (1240)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 8123 Dynamics: seismotectonics
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
DE: 9350 North America
SC: Tectonophysics [T]
MN: 2007 Fall Meeting