1. Signals and Trends in Borehole Strainmeter Data Strainmeter Short Course 2009 Earthscope Meeting, Boise May 12, 2009 Strainmeter Short Course 2009 Earthscope Meeting, Boise May 12, 2009

2. Signals and Trends State of borehole compression Earth tides Barometric pressure response Seismic signals Non-tectonic signals Strain transients

3. Trends: Borehole Dominant signal over months is borehole relaxation. Long term trend should be areal compression. 3 gauge areal strain = (CH0+CH1+CH2)/3 120° 90° CH0 CH2CH1 30°

4. Trends: Borehole Extension +ve areal strain=(CH0+CH2+CH3)/3 “Classic Trends” Digital Counts (x10 3 ) 21.3 Microstrain Compression -ve B087, Ford Ranch

5. Trends: Borehole Extension +ve Digital Counts (x10 3 ) 0.4 Microstrain Compression -ve B087, Ford Ranch

6. Network State of Compression Extension +ve Compression Rate (nanostrain/day) Compression -ve December 15, 2008 - April 15, 2009 Extension +ve Compression -ve PBO BSM Network, Compression Rate 74% in compression Days since installation

7. Extension and steps B040, York, Northern California GTSM21 designed to operate under compression Digital Counts (x10 3 ) 147.3 Microstrain

8. 16.6 Microstrain Extension and steps B040, York, Northern California Digital Counts (x10 3 ) More likely to see steps in non-compressional BSM 21% of BSMs record steps 58% of non compressional BSMs record steps

9. Extension and steps B040, York, Northern California Rate of steps decrease as BSM turns to compression Digital Counts Digital Counts (x10 3 ) 2.7 Microstrain

10. Extension and steps Source of step unknown: Nothing on other gauges Nothing on B009 or B011 16.8 Microstrain B010, PGC, Vancouver Island, Canada Digital Counts (x10 3 ) B009 B010 B011 168m 250m

11. Trends: Seasonal B009, PGC B009, PGC, Vancouver Island, Canada Digital Counts (x10 3 )

12. Trends: Seasonal B009, PGC B009, PGC, Vancouver Island, Canada microstrain Herb Dragert reports farmer irrigating fields

13. Hydrostatic Coupling B006, Shores, Washington Possibly hydrologically coupled Little or no shear strain Drifting phase in tidal signal Little strain accumulated over 3.5 years 4.3 Microstrain Digital Counts (x10 3 )

14. Tidal signal Expect optimal performance in the tidal band M2 and O1 peaks should be visible in the spectrum Areal and shear consistency

15. Tidal signal CH0 CH1 CH2 CH3 microstrain B018, Delphi, Seattle, WA Detrended gauge data

16. Tidal signal M2 O1 dB/cpd Band passed gauge data, 0.25 to 4 cpd (3 years) B018 Delphi, Seattle, WA

17. Tidal Consistency 120° CH0 CH2CH1 120° 90° CH3 CH1 3 gauge areal strain (CH0+CH1+CH2)/3 2 gauge areal strain (CH1+CH3)/2

18. Tidal Consistency Areal ±10° 69% Shear ±10° 65% Areal ±25 44% Shear ±25% 65% Strainmeters M2 Phase Difference M2 Amplitude Ratio

19. B018, Delphi, Seattle, WA Barometric Response Barometric Pressure mbar Pressure increase = gauge compression CH0 CH1 CH2 CH3 microstrain Tides removed

20. Barometric Response Barometric Pressure mbar CH0 CH1 CH2 CH3 microstrain B018, Delphi, Seattle, WA Pressure increase = gauge compression Tides & barometric response removed

21. Barometric Response Average barometric response coefficients ParkfieldOlympic P. Strainmeters AnzaMSHYSORN.CMojave Typical Range 2-10 nanostrain/millibar

22. 9-12 second calibration signal, 30 minutes past the hour Null point before and after signal 9-12 second calibration signal, 30 minutes past the hour Null point before and after signal High frequency signals Digital Counts (x10 6 ) B022, May 31, 2008, 1-sps data

23. High frequency signals Digital Counts

24. B022 Spectrogram, May 31, 2008 B006 M6.6 Mid Indian Ridge Calibration spikes Microseism CH1 CH2 CH0 CH3

25. Seismic Shear: M5.4 LA, July 29, 2008

26. March 19, 2009 M7.6 Tonga, March 19, 2009 Olympic Peninsula: Seismic Shear

27. Non Tectonic Signals

28. Noise: Rainfall Several of the PBO BSMs show strain signals correlated with rainfall When looking at transients check the rainfall measurements, all PBO sites have rain gauges

29. Noise: B022 Rainfall B022, Oregon CoastB022, Seaside, Oregon Coast Site in river flood plain, prone to flooding Digital Counts Rainfall (mm/hr)

30. Noise: Pathfinder, Anza Co-located, Pathfinder strainmeters Microstrain B082 B089 Microstrain CH0 CH1 CH2 CH3

31. Noise: Pathfinder, Anza Co-located, Pathfinder strainmeters B082 B089 Microstrain

32. Noise: B001 Pumping B001, Golbeck, Washington Digital Counts 0.1 Microstrain 2 gauges compression 2 gauge in extension PNW: B001 B045 Anza: B082 B089 B088

33. Noise: Storms Digital Counts (x10 3 ) B012, Ucluelet, Vancouver Island, Canada February 4, 2006 February 4, 2006 February 5, 2006

34. Noise: Downhole Temperature B022, Seaside, Portland Counts Temperature °C Downhole Temperature Digital Counts (x10 3 ) Increase in downhole temperature => compression

35. Noise: Downhole Temperature B012 restart, February 11, 2009 Temperature °C Downhole Temperature Digital Counts (x10 3 ) Instrument restart Increase in downhole temperature => compression

36. Solar Noise Noise is introduced when solar panels start to charge up in early morning. Visible in the 1 and 20-sps data set. PBO engineers found that rerouting cables helped.

37. Solar Noise: 1 sps B916, Mojave, March 20, 2008B058 2009:083 1sps Spectrum CH1 CH2 CH0 CH3

38. Solar Noise: 20 sps CH1 CH2 CH0 CH3 B916, Mojave, March 25, 2008

39. Tectonic Signals

40. A Strain Transient: Cascadia ETS B012 B009 B004 B003 B005-7 B001 Cascadia Episodic Tremor and Slip

41. A Strain Transient: Cascadia ETS B012 B009 B004 B003 B005-7 B001 B018 Cascadia Episodic Tremor and Slip B004, Hoko Falls, WA 2Ene Strain Eee-Enn

42. Cascadia Episodic Tremor and Slip 2Ene Strain Eee-Enn 2007 Tremor 2005 Tremor B004 microstrain

43. Cascadia Episodic Tremor and Slip 2Ene Strain 2008 Tremor B004 microstrain

44. Spring 2008 Cascadia ETS B012 B009 B004 B003 B005-7 B001 B018 microstrain Pacific Northwest BSMs: Shear strain propagation of tremor (www.pnsn.org) May 4 May 15 May 31 April 2008May 2008

45. 2009 Cascadia ETS ? B012 B009 B004 B003 B005-7 B001 B018 Pacific Northwest BSMs: Shear strain microstrain April 2009May 2009

46. ETS March 2009, B012, Vancouver Island B012, Ucluelet, March 2009: Processed Gauge Data microstrain Detrended gauge data Tide removed Tide and pressure removed

47. ETS March 2009, B012, Vancouver Island microstrain Tensor Strain Detrended gauge data Tide removed Tide & pressure removed

48. Creep Events, Parkfield Middle Mountain Area, Parkfield PBO-BSM

49. Creep Events, Parkfield Middle Mountain Area, Parkfield PBO-BSM 2Ene Strain Eee-Enn B073 Varian, Parkfield microstrain Right lateral creep events

50. Creep Events, Parkfield B073 Varian, Parkfield 1-sps Gauge Data

51. Yellowstone Tremor

52. microstrain 2Ene Strain Eee-Enn Eee+Enn B208, Lake Junction, Yellowstone Dec 27 M3.5 Dec 29 M3.9 Jan 2 M3.5 Detrended areal and shear strain