Submit Abstracts for GSA 2009 Session T75: "Slow Slip and Non-Volcanic Seismic Tremor..."

Forwarded invitation from Justin Rubinstein, USGS Menlo Park:

Dear Colleagues,

We'd like to encourage you to submit an abstract for GSA 2009 session T75. "Slow Slip and Non-Volcanic Seismic Tremor in Cascadia and Beyond: Observations, Models, and Hazard Implications."  This session aims to explore the many different slow-slip and tremor phenomena that have recently been discovered in an ever-increasing number of localities. There is a focus on the Cascadia region, as the meeting will be taking place in the middle of the Cascadia subduction zone in Portland, OR, October 18-21.  We look forward to your contribution to this important and timely topic.

Abstract submissions are due August 11, 2009:
http://gsa.confex.com/gsa/2009AM/cfp.epl

Best Regards

Monica, Carene, Evelyn, and Justin

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T75. "Slow Slip and Non-Volcanic Seismic Tremor in Cascadia and Beyond: Observations, Models, and Hazard Implications."

Conveners:  M. Maceira & C. Larmat (Los Alamos), E. Roeloffs and J. Rubinstein  (USGS)

The recent discovery of non-volcanic tremor and slow aseismic slip has resulted in a flurry of research activity across many geologic and geophysical disciplines. The two phenomena are often coupled and recurrent, in which case they are called Episodic Tremor and Slip (ETS). Current research suggests that non-volcanic tremor and slow slip are both members of a family of unusually slow earthquakes. These slow earthquakes occur in diverse tectonic environments and appear to have the same mechanism as ordinary earthquakes, but differ from normal earthquakes in their source location and moment-duration scaling. Unlike ordinary earthquakes, which grow explosively in size with increasing duration, slow earthquakes, whether large or small, grow at a constant rate.   

The hazard implications of tremor and slow-slip are also quite important. Tremor and slow-slip are typically found on the deep extension of faults, just below the region of the fault that produces the more familiar, and dangerous, "ordinary" earthquakes. Thus, the slip from these slow events could load, or even trigger, large earthquakes in the shallower portion of the fault zone.  For this reason alone they merit intense study. Their recent discovery in different tectonic environments around the globe (Japan, Cascadia, New Zealand, Costa Rica, Taiwan, California) also points out that there is much that we still have to learn about the conditions propelling rupture on deep faults, and that earthquake science is a field where further fundamental discoveries may require the synergy of observational and material Earth science.  

Recent deployment of hundreds of seismometers, GPS stations, borehole strainmeters, and other geophysical instrumentation as part of the Earthscope experiment has enabled identification of nearly 40 isolated ETS events along the Cascadia forearc. ETS events are observed from northern California to Vancouver Island, Canada. However, many questions remain unanswered as the underlying cause of these newly identified events, or their impact on general Cascadia seismicity, their distribution and periodicity along strike, and their impact on the depth extent of the eventual megathrust rupture. Given its location in Portland, the center of the Cascadia subduction zone, the 2009 GSA meeting is the perfect venue to gather those involved in conducting research related to this newly discovered branch of the earthquake family.