1. Recent ETS results in NW Washington Tremor Locations and Migration during last four ETS events Locked Zone relative to Tremor Location Inter ETS Tremor Swarms: Adds up to nearly as much as ETS tremor Gutenberg-Richter Power-Law Distribution N = A  -0.6 = a10 -0.9Mw L = A  1/n n = 2-3 Tremor depths beneath arrays are near plate interface based on S-P times from cross correlation 100 LFEs within 100 m of each other are on plate interface Down-dip limit of tremor coincides with down-dip limit of low-velocity zone below plate interface (CAFE result) Creager, Wech, Vidale, Sweet, Ghosh, Melbourne, Houston and Abers

2. Tremor Migration for four ETS events Wech, Creager and Melbourne, JGR, submitted

3. Tremor and Slip summed over 4 ETS events

4. 2004, 2005, 2007 ETS Sharp western boundary to tremor Consistently 75 km from tremor to 40% locking Crustal earthquakes stop at eastern tremor boundary Tremor is most active over water

5. ETS vs inter-ETS tremor Wech, Creager and Melbourne; JGR, submitted

7. Gutenberg-Richter Power-Law Distribution of Tremor Swarms N = A *  -0.6 log 10 N=a10 -bM w b=0.9 if moment proportional to duration Creager and Wech

8. Tremor Swarm Duration vs Length Slope=1/2 Slope=1/3 Slope=1 Creager and Wech

9. An hour of LFEs

11. LFEs locate ~20km east of BS array at depth of ~47km, which is the depth to the plate interface at that location. Individual LFE S-P times vary by no more than 0.03s, suggesting they all locate within several hundred meters of each other.

12. La Rocca, Science, next week Checking location by cross-correlation of horizontal with vertical across 5-minute windows S-P timeZero lag

13. La Rocca, Science, 2009 Checking location thrice S-P time Beam (rainbow) and envelope (green stars)

14. LaRocca et al., Science, 2009

15. Schematic interpretation of receiver function results.

16. Abers, MacKenzie, Rondenay, Zhang, Wech, Creager, submitted, Geology

18. ETS Every 15 months Creager & Wech * BS Array

19. Inter ETS Tremor Feb 2007 to April 2008 some patches repeat up to 5 times Creager and Wech

22. 84 sensors in a km 2, Caught 8 days with light tremor last March, then 17 days of heavy tremor passing directly underneath last May Time (days) UW dense array pilot study 1 km