Abstract and Pictures of my family

Submitted by kjensen on Wed, 2008-09-10 04:55.

Well, I have finished my abstract and submitted it to AGU at about 2200 UTC today. So, here it is. I will be working on the poster over the next little while, and I may just do it about a month before AGU that way I can have it fresh in my mind, but I will be working on it throughout the semester. I will post the poster once I finish it.

Seismicity of the Oaxaca Segment of the

Middle American Subduction Zone

Convergent plate boundaries generate potentially devastating great earthquakes when tectonic stresses accumulate on the plate interface. The Oaxaca segment of the Middle-America subduction zone offers an ideal opportunity for detailed studies of the plate interface due to its relatively rapid convergent rates, unusual shallow subduction angle, and ~50 km trench-to-coast distances that brings the seismogenic and transitional zones of the plate interface ~250 km inland. The short recurrence interval (decades) of megathrust events also allows us to compare current seismicity to past events in detail to examine the asperity and gap hypotheses to better characterize the seismic hazard. A network of seven broadband three-component seismometers was deployed in summer 2006 over an area of ~300 km west-east and 200 km north-south with nominal 80 km station spacing, providing the means to examine seismicity in detail for the first time in this region. We use the Antelope Software package to organize the first nine months of recorded waveforms, perform analyst event detections, generate source locations, and compute local magnitudes. We detected and located over 3000 earthquakes with this method. The bulk of the earthquakes follow the coastline with these hypocenters clustering near the plate interface, but we also detected a number of deeper (>40 km) intraslab earthquakes further inland. The microseismicity we detected outlines the down-dip end of the seismogenic zone near 25 km depth, consistent with the depth and inland extent of previous megathrust events. When the seismicity is compared with other recent studies, we find a clear spatial relationship that suggests a downward progression of deformation with the subducting plate from interplate seismicity to slow-slip events to non-volcanic tremor to intraslab earthquakes. We are also beginning to see temporal relationships between seismicity and episodic tremor and slip, including a swarm of 50 earthquakes at the down-dip end of the seismogenic zone with bursts of activity followed by pulses of non-volcanic tremor activity.