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Borehole Seismology in Urban Setting

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Seminar given by Professor Peter Malin in İstanbul University.

Seminar given by Professor Peter Malin in İstanbul University.

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  • The diagram for Reason 1 compares seismograms recorded on the surface and at 250 m immediately below the surface site. The surface seismograph’s signals are dominated by wind and cultural noise, so much so that the small M~1 microearthquake is only known from the downhole data. How many such events have been missed by the local seismic network, based on whose data the surrounding area has been reported to be aseismic.
  • The diagram for Reason 2 shows the dramatic effects of strong near surface attenuation and scattering. The seismograms on the top and bottom of this Figure are for the same 0.5 microearthquake, the differences in waveforms results from loss of high frequency signal by both energy damping and scattering. Ultimately, as illustrated in the next Figure, the loss is such that the signals of many small earthquakes never make it to surface stations, leading to a cut off in event detection and location. In many places this cut off is higher than M~1 to 2 events, suggesting that many 10s of events are going unnoticed.
  • A microearthquake swarm captured by the LVEW borehole seismograph that went unnoticed by the local surface seismic network of 25 stations. Because the surface net’s detection/location threshold is for events bigger than M~0.7 only the M~1 was included in the catalogue for this period. The borehole sensor is a 3 component 4.5 Hz seismograph located at 2.4 km depth, in 115oC water.
  • A microearthquake swarm captured by the LVEW borehole seismograph that went unnoticed by the local surface seismic network of 25 stations. Because the surface net’s detection/location threshold is for events bigger than M~0.7 only the M~1 was included in the catalogue for this period. The borehole sensor is a 3 component 4.5 Hz seismograph located at 2.4 km depth, in 115oC water.
  • Transcript

    • 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...
    • 43.
    • 44.
    • 45. The situation
      downunder?
      IESE
      GEOPHONE
      You said “stick’em up!”
      Good heavens...I am borehole seismologist, not a social psychologist!

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