Coherence and Spectra Analysis of the USARRAY TA PY Posthole Test Array

Transcription

1 Coherence and Spectra Analysis of the USARRAY TA PY Posthole Test Array Frank Vernon Scripps Institution of Oceanography University of California, San Diego David Thomson Dept. Math and Statistics Queens University 7 May 018

2 Outline USArray Alaska Deployment Motivation PFO Testbed IRIS PSD results Spectra and Coherences Event data Conclusions

3 TA Alaska Sensor Emplacement The Lund-Drill is designed for TA in Alaska: 1600 lbs Sling load weight 8% Augering 3% Backhoe 69% Downhole Hammer NEED: a hole in rock, frozen ground or up to M into soils. Hammer drill, NK Drill in Skyvan, bound for Middleton Island Hammer Drilling, AK.SCRK Mike Lundgren auger in Palmer AK

4 PFO PY Posthole Installation

5 Figure 1: Instrumental setting at Piñon Flat Observatory (red triangle on overview map). PY Array - Piñon Flat Observatory A LSM EW LSM NS LSM NW SE Pinon Flat 1 RLG small array medium array large array LSM 00 m B C

6 Piñon Flat PY Array

7 Piñon Flat PY Array 90 meter aperture 6 meter minimum spacing

8 Piñon Flat PY Array 00 meter aperture 3 meter minimum spacing

9 Piñon Flat PY Array 1080 meter aperture 730 meter minimum spacing

10 Nominal STS and Trillium 10 PH Responses Broadband Sensors 10 Sec Long Period Corner

11 Nominal STS and Trillium 10 PH Responses Broadband Sensors 10 Sec Long Period Corner STS - ~40 Hz

12 Nominal STS and Trillium 10 PH Responses Broadband Sensors 10 Sec Long Period Corner STS - ~40 Hz T10PH - ~00 Hz

13 Nominal STS and Trillium 10 PH Responses Broadband Sensors 10 Sec Long Period Corner STS - ~40 Hz T10PH - ~00 Hz Similar response < 10 Hz

14 BHZ Sensor Comparison PDFs 1 Jan - Dec Nearly identical PDFs for both sensors

15 BHN Sensor Comparison PDFs 1 Jan - Dec Slightly more long period noise on Trillium

16 BHN Sensor Comparison PDFs 1 Jan - Dec Slightly more long period noise on Trillium Slightly quieter long period noise on STS

17 BHE Sensor Comparison PDFs 1 Jan - Dec Slightly more long period noise on Trillium

18 BHE Sensor Comparison PDFs 1 Jan - Dec Slightly more long period noise on Trillium Slightly quieter long period noise on STS

19 GSN-PY BHZ Sensor Comparison 1 Jan - Dec Similar performance between STS- Posthole and STS-1

20 GSN-PY BHN Sensor Comparison 1 Jan - Dec Improved performance of STS- Posthole over STS-1

21 AZ-PY BHZ Sensor Comparison 1 Jan - Dec Improved performance of STS- Posthole over surface STS-

22 AZ-PY BHN Sensor Comparison 1 Jan - Dec Improved performance of STS- Posthole over surface STS-

23 STS HHZ BPH01-BPH0 6 Meter Separation multi taper spectra 00 sps 600 sec windows 600 sec offset 140 windows 10 tapers 6 NW (time bandwidth product)

24 STS HHZ BPH01-BPH0 6 Meter Separation multi taper spectra 00 sps 600 sec windows 600 sec offset 140 windows 10 tapers 6 NW (time bandwidth product) multi taper coherence Section Average MSC ****

25 STS Coherence BPH01-BPH0 6 Meter Separation HHZ MSC Section Average MSC ****

26 STS Coherence BPH01-BPH0 6 Meter Separation HHZ MSC HHN MSC << HHZ 0.01 Hz to 0.1 Hz > HHZ 1 Hz to 10 Hz Section Average MSC ****

27 STS Coherence BPH01-BPH0 6 Meter Separation HHZ MSC HHN MSC << HHZ 0.01 Hz to 0.1 Hz > HHZ 1 Hz to 10 Hz HHE MSC Similar to HHN Section Average MSC ****

28 Trillium 10 PH HHZ BPH03-BPH04 6 Meter Separation multi taper spectra 00 sps 600 sec windows 600 sec offset 140 windows 10 tapers 6 NW multi taper coherence FLV-py 04 Z

29 Trillium 10 PH HHZ BPH03-BPH04 6 Meter Separation multi taper spectra 00 sps 600 sec windows 600 sec offset 140 windows 10 tapers 6 NW multi taper coherence Section Average MSC **** FLV-py 04 Z

30 Trillium 10 PH Coherence BPH03-BPH04 6 Meter Separation HHZ MSC HHN MSC << HHZ 0.01 Hz to 0.1 Hz > HHZ 1 Hz to 10 Hz HHE MSC Similar to HHN Section Average MSC ****

31 Trillium 10 PH Coherence BPH03-BPH04 6 Meter Separation HHZ MSC HHN MSC << HHZ 0.01 Hz to 0.1 Hz > HHZ 1 Hz to 10 Hz HHE MSC Similar to HHN Section Average MSC ****

32 Trillium 10 PH Coherence BPH03-BPH04 6 Meter Separation HHZ MSC HHN MSC << HHZ 0.01 Hz to 0.1 Hz > HHZ 1 Hz to 10 Hz HHE MSC Similar to HHN Section Average MSC ****

33 HHZ 6 Meter Separation Section Average MSC **** BPH01-BPH0 STS Section Average MSC **** BPH03-BPH04 Trillium 10 PH FLV-py 04 Z

34 MSC 6 Meter Separation BPH01-BPH0 STS BPH03-BPH04 Trillium 10 PH Section Average MSC **** Section Average MSC ****

35 STS Coherence - 6 meters vs 870 meters BHZ BHN BHE Section Average MSC **** Section Average MSC ****

36 Section Average MSC **** STS Coherence - 6 meters vs 870 meters BHZ FLV-py 13 Z Section Average MSC **** BHN BHE

37 Potential Horizontal Response Issues BPH01-BPH0 STS BPH03-BPH04 Trillium 10 PH FLV-py 0.HH E FLV-py 04 E Percent Order Statistics 140 Sections Percent Order Statistics 140 Sections

38 Potential Horizontal Response Issues BPH01-BPH0 STS BPH03-BPH04 Trillium 10 PH FLV-py 0.HH E FLV-py 04 E Percent Order Statistics 140 Sections Percent Order Statistics 140 Sections

39 Signatures of Solar modes in BPH09 N Spectra Solar Mode Refs 007 PIEEE07 Thomson et al 01 GJI Thomson and Vernon 016 IEEE Thomson and Vernon Multiple-taper spectrum, K= p T p 1 8 Data from PY/163-1M/BPH_09_N_016d078.1M 1 sect, K= 8 BT pt/sect, Rayleigh uhz 99% 90% % T 8 p 4 7

40 STS HHZ BPH01-BPH0 Coherogram Section Average MSC **** ***

41 Coherogram ***

42 Coherogram Local Events ***

43 Coherogram Teleseismic Event ***

44 PY STS-, Trillium 10BH 00 m

45 Cohero and Spectragrams Spectragram- Spectragram-

46 Coherence and Spectra One-day average coherence One-day average spectra

47 016 Year Long 6 meter Coherogram 01-0-HHE 01-0-HHN 01-0-HHZ HHE HHN HHZ

48 016 Year Long 330 meter Coherogram 0-08-HHE 0-08-HHN 0-08-HHZ Distance ~ 330m HHE HHN HHZ

49 016 Year Long 780 meter Coherogram HHE HHN HHZ 09-1-HHE 09-1-HHN 09-1-HHZ

50 016 BHZ Coherence

51 016 BHN Coherence

52 016 BHE Coherence

53 Three Teleseisms

54 Mw 6.7 Gulf of California 017 SRL Donner et al

55 Mw 6.7 Gulf of California 017 SRL Donner et al

56 Mw 6.7 Gulf of California Array Derived Rotation and Strain 017 SRL Donner et al.

57 Mw 6.7 Gulf of California Comparison with PFO Strain and Rotation 017 SRL Donner et al.

58 Summary USArray Posthole Deployment provides consistent high quality data STS and Trillium 10 PH show similar performance All array elements with the same orientation are have highly coherent ground noise in the microseism band Outside the microseism band the coherence of ground noise drops significantly as a function of distance. Earthquake signals exhibit higher coherence across a wider bandwidth Small Aperture Arrays of posthole broadband sensors can effectively measure strain and rotation of earthquakes.