1. Real-time Monitoring of Slip Triangles: Tremor Activity –Average envelope seismogram amplitudes in tremor passband –Active Tremor = black triangles Arrows: GPS Short-term Velocity –50-day GPS site velocities after long-term velocity is removed –Slow Slip = large arrows pointing towards trench

2. January-February 2007

3. June-July-August 2007

4. April-May-June 2008

5. NVT Location Approach Filtered envelope waveforms STA/LTA to find NVT bursts Pick relative times of good S/N arrivals –By hand and/or automated 1D inversion for locations Analyze for patterns in space and time

6. NVT Migration in Southern Cascadia 2005-2006: Hand-picked vs. Automated

7. NVT Migration Along All of Cascadia 2007-2008 (Automated) Still preliminary, but find long migrating episodes that overlap in time despite being separated by >100 km Three 2007-2008 events are more interrelated along- strike than all events in previous few years

8. NVT Locations So Far Still plenty of work for us to do in the northern half Beginning to see a persistent gap at OR-CA border NVT band primarily between 30-40 km slab contours Matches some aspects of slab curvature

9. Integrating ETS with Earth Structure and Geology ETS Periodicity Surface Wave Crust Structure Body Wave Mantle Structure Brudzinski & Allen, 2007 Arc volcanism Schmidt et al., 2008