Seminar given by Professor Peter Malin in İstanbul University.

1. ISTANBUL UNIVERSITY ENGINEERING SCIENCES - 19 SEPT 2011 BOREHOLE SEISMOLOGY IN URBAN SETTINGS Peter Malin & IESE StaffInstitute of Earth Science & EngineeringUniversity of Aucklandp.malin@auckland.ac.nzand many SAFOD, LVEW, Basel, and other collaborators IESE Staff

2. Talk Outline Background: What’s the problem – why borehole seismology in urban settings…..???

3. Two examples…. Auckland HarratRahat ….living in Istanbul, you can probably think of a third!

4. Talk Outline Background: What’s the problem – why borehole seismology in urban settings…..??? Seismic city-noise in Auckland New Zealand Tea Time ….2 times a day

5. Talk Outline Background: What’s the problem – why borehole seismology in urban settings…..??? Surface seismic station – Riverhead, Auckland. NZ Day Night

6. REASON #1. NOISE REDUCTION! Results of test station installed at Riverhead, NZ, depth of 245m 1 min 1 minute Same small event M~1 Borehole Surface

7. Talk Outline More Background: Installation map Observatory versus depth chart Current standard seismographs Motivation for borehole observatories Detection Location Imaging Research Some Examples Basel Switzerland In progress – CAGS Donghai 5.2 km Observatory

8. Where does IESE work?

9. LVEW SAFOD PH TCDP PBO (113) Stations SAFVA PBO PALM ORO&QH 1.ii Observatory versus depth chart Depth Current Standard 5.2 km 195 C 4.5 Hz Definitions x & y = Surface z = Borehole In meters 4096 CCDP SAFOD MH SAFOD MH 2048 BASEL PARALANA 1024 GIPPS 512 BASEL SPEC SCO2 ICO2 256 PARKFIELD MONTY SAUDI WAIRAKEI 128 COSO KRAFLA “x, y” Surface Net “z” Vertical Net “ x, y, z” Borehole Net 64 32 SUMA PUNA 16 PARALANA 4 2 1 OZ PUNA PALM LOMA KRAFLA LV97 SAFOD 1 2 4 8 16 32 64 In Progress No. of stations

10. 1.iii Current standard instruments Shallow – “posthole” – 1-to-10 m depths Fixed (ungimbaled) sensors + 10 vertical installation 60 mm OD sonde 3-and 6-component sensors seismometers &/or accelerometers 2 Hz seismometers up to 500C MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 1950C 40 cm

11. 1.iii Current standard instruments Deep – “Observatory” – 1-to-5 km depths Gimbaled sensors 90 mm OD sonde + 200 tilted borehole 3-and 6-component sondes seismometers &/or accelerometers 2 Hz seismometers up to 500C MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 1950C 110 cm

12. 1.iii Current standard instruments Multilevel – pipe installation “Array” – 0-to-2 km depths 8-to-24 Fixed sensors 60 mm OD sonde + 900 tilted borehole Passive 3-component sensors seismometers 15 Hz seismometers to 800C pipe cable sensorskid recorder & boffins cable & spool

13. 1.iii Current standard instruments Cableless – downhole recorder “Autonomous” – 0-to-2 km depths Gimbaled sensors + 24 bit 2 kHz recorder 110 mm OD sonde + 200 tilted borehole 3-and 6-component autonomous sondes Seismometers/accelerometers/recorder 0.1 Hz enhance SM64 up to ? 2 Hz seismometers up to 500C MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 800C Batteries Recorder Sensors

14. Talk Outline More Background: Installation map Observatory versus depth chart Current standard seismographs Motivation for borehole observatories Detection Location Imaging Research Some Examples Basel Switzerland In progress – CAGS Donghai 5.2 km Observatory

15. What happens to a seismic wave as it approaches the earth’s surface? MEQ Recorded in 4.66 km stimulation Well – Basel 500 ms Depth 4661 m Basel1 C1 Basel1 C2 Basel1 C3 Basel1 C4

16. Spectral analysis of Basel MEQ versus station < 100 Hz 500 ms 2740 m < 20 Hz 500 m 542 m 317 m 553 m 1213 m

17. What happens to a seismic wave as it approaches the earth’s surface? M ~ 0.5 MEQ Data from 3.3 km deep LVEW see: http://quake.wr.usgs.gov/cgi-bin/heliexp.pl Surface seismograph Borehole seismograph

18. SIGNAL REDUCTION BY INTRINSIC ATTENUATION Borehole Seismic Array Spectral Content as a function of depth - Note Log scales 0 m 100 m 200 m 300 m 400 m >50 Hz S & P P 400 0 12.5 25 50 100 Hz 25Hz 4 12.5 25 50 100 Hz >50 Hz S 400 0/4 0 15Hz 12.5 25 50 100 Hz

19. . Event Detection – 3.3 km borehole in Mammoth CA 1 MIN M~ 1 limit of ~ 15 station surface net M~ -1 in 2.7 km observatory M~ -2 in 2.7 km observatory

20. Event Detection – 3.3 km borehole in Mammoth CA

21. Net of Reasons 1 - 3: Signal-to-Noise Improvement with Depth & Signal Frequency Depth meters 1 Hz 10 Hz 100 Hz 1000 Hz 4096 + + 2048 1024 512 256 128 64 32 16 Signal-to-Noise 4 loss due to scattering & attenuation 2 1 1 2 4 8 16 32 128 256 512 Signal to Noise Ratio

22. The Gutenberg-Richter Relation. 1 MIN M~ 1 M~ -1 LVEW December 2007 Seismicity on 2.7 km deep 4.5 Hz 3-component- sonde vertical channel. Analog chart display

23. Detection & Location Improvement with Depth ? ? -2 -1 0 1 2 3 Magnitude

24. IMAGING OF SUBVERTICAL VELOCITY STRUCTURE & EVENT LOCATION!

25. Depths vs. No. of Seismic Stations: Monitoring Objectives Source Rupture Propagation EQ Physics Fault Structure Statistics Locations Tomography Seismotectonics

26. Some Lessons Learned Along the Road to Seismology in the Source Lesson I: How the road divides Low RoadMiddle RoadHigh Road Inside casing wireline Inside casing wireline Outside casing tubing Few levels <10 Several Levels >10 Many Levels >100 Digital component Digital component Digital component at surface at analog sensors Fully (e.g. MEMS) Analog components Analog components Analog components Armored Cu cables Hybrid OF to surface - Sensors Cu between levels No Power Power Power Low T & P Mid T & P High T & P < 100 C ~ 150 C > 150 C < 3 km ~ 3 km > 3 km Donated winch Used winch Special installation winch Local Univ. & Industry Nat. Institutes & Industry Internat. Organ. & Industry

27. Some Lessons Learned Along the Road to Seismology in the Source Lesson II: The Do’s, Don’ts, and Maybe’s Do’sMaybe’sDon’ts Triple fluid barriers Double fluid barriers Single fluid barrier Welded seals Metal-metal seals O-ring seals clamping/weight>>1 clamping/weight >1 clamping/weight ~1 Passive clamps Hydraulic ram clamps Electrical ram clamps Passive TS Cu cable Single power cable Multiple power cable Armor+jacket+fill cable Jacket+fill cable jacket cable Passive sensors Low power sensors High power sensors electrically isolated case grounded case downhole ground for High T & P for Mid T & P for Low T & P > 150 C ~ 150 C < 100 C > 3 km ~ 3 km < 3 km Special winch Used winch Donated winch Internat. Institutes & Ind. Nat. Institutes & Industry Local Univ. & Industry

28. ...and don’t forget the SAKE test...

29. Talk Outline More Background: Installation map Observatory versus depth chart Current standard seismographs Motivation for borehole observatories Detection Location Imaging Research Some Examples Basel Switzerland In progress – CAGS Donghai 5.2 km Observatory

30. With many thanks to the staff of Geopower Basel BIG BOOM IN BASEL The Big Boom in Basel or How Earthquakes (Nearly) Sank a Major EU Industry: Is Turkey Next? Peter Malin, Eylon Shalev, and Dan Kahn Institute of Earth Science and Engineering University of Auckland, New Zealand

31. BIG BOOM IN BASEL Induced Earthquakes and Geothermal in Downtown Basel, Switzerland “Hot/Dry Rock” well Basel from space

32. The challenge at, for example, St Johann: Seismology and meat packing

33. The challenge at, for example, St Johann: the Swiss rail service

34. Serious Seismologist MEMS Accelerometer Gal’perin Seismometer WeakLink Fishing Tower Signal Cable Stress Member

35. Railroad track A typical 400 m installation: St. Johann

36. OT-2 deep well: 2754 m 155º C

37. Basel network Map view N Block view Injection site Injection site OT-1 OT-1,2 OT-2

38. BIG BOOM IN BASEL – the connection between earthquakes and fluid flow Injection well Microearthquakes “Cementing” Microearthquakes Injection well MAP CROSS SECTION

39. What happened? December 2006 03 04 05 06 07 08 09 10 11 12 13 14 200 100 4 2 0 4 3 2 1 0 300 200 100 0 1 every 20 s Water Pressure bars Number of event per hour: Detected Located Magnitude Magnitude Legal Limit = 3.4 Legal Limit = 3.4 D J F M A M J J A S O N D J F December 2006 – February 2008

40. October 18, 2006 - 7:56 AM News Swiss emergency officials have been participating in a huge earthquake preparedness exercise ....... .... disaster simulation coincides with the 650th anniversary of the great Basel earthquake of October 18, 1356 – a 6.5 magnitude quake which destroyed most of the city.

41. December 9, 2006 - 6:43 PM Man-made tremor shakes Basel ! Drilling for a planned geothermal power plant triggered a small earthquake that caused minor damage to buildings. ......The Basel City prosecutor has launched an investigation to find if the company behind the Deep Heat Mining project should pay for repairs..... Prosecution .....The prosecutor's office launched its investigation on Friday evening. The police have already seized computer data....

42. Hand over those earthquakes, you seismologist scum... But sir! I was just working on my PhD...

45. The situation downunder? IESE GEOPHONE You said “stick’em up!” Good heavens...I am borehole seismologist, not a social psychologist!