Borehole Seismology in Urban Setting

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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.
  • Borehole Seismology in Urban Setting

    1. 1. ISTANBUL UNIVERSITY ENGINEERING SCIENCES - 19 SEPT 2011<br />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<br />IESE Staff<br />
    2. 2. Talk Outline<br />Background: <br />What’s the problem – why borehole seismology in urban settings…..???<br />
    3. 3. Two examples….<br />Auckland<br />HarratRahat<br />….living in Istanbul, you can probably think of a third!<br />
    4. 4. Talk Outline<br />Background: <br />What’s the problem – why borehole seismology in urban settings…..???<br />Seismic city-noise in Auckland New Zealand<br />Tea Time ….2 times a day<br />
    5. 5. Talk Outline<br />Background: <br />What’s the problem – why borehole seismology in urban settings…..???<br />Surface seismic station – Riverhead, Auckland. NZ<br />Day<br />Night <br />
    6. 6. REASON #1. NOISE REDUCTION!<br />Results of test station installed at Riverhead, NZ, depth of 245m<br />1 min<br />1 minute<br />Same small event M~1<br />Borehole<br />Surface<br />
    7. 7. Talk Outline<br />More Background: <br />Installation map<br />Observatory versus depth chart<br />Current standard seismographs<br />Motivation for borehole observatories <br />Detection<br />Location<br />Imaging<br />Research<br />Some Examples<br />Basel Switzerland<br />In progress – CAGS Donghai 5.2 km Observatory<br />
    8. 8. Where does IESE work?<br />
    9. 9. LVEW<br />SAFOD PH <br />TCDP<br />PBO <br />(113) Stations<br />SAFVA <br />PBO<br />PALM<br />ORO&QH <br />1.ii Observatory versus depth chart<br />Depth<br />Current Standard<br />5.2 km 195 C 4.5 Hz<br />Definitions<br />x & y = Surface<br />z = Borehole<br />In meters<br />4096<br />CCDP<br />SAFOD MH<br />SAFOD MH<br />2048<br />BASEL<br />PARALANA<br />1024<br />GIPPS<br />512<br />BASEL<br />SPEC<br />SCO2<br />ICO2<br />256<br />PARKFIELD<br />MONTY<br />SAUDI<br />WAIRAKEI<br />128<br />COSO<br />KRAFLA<br />“x, y” <br />Surface Net <br />“z” <br />Vertical Net<br />“ x, y, z” <br />Borehole Net<br />64<br />32<br />SUMA<br />PUNA<br />16<br />PARALANA<br />4<br />2<br />1<br />OZ <br />PUNA<br />PALM<br />LOMA<br />KRAFLA<br />LV97<br />SAFOD<br />1<br />2<br />4<br />8<br />16<br />32<br />64<br />In Progress<br />No. of stations<br />
    10. 10. 1.iii Current standard instruments<br /> Shallow – <br />“posthole” – 1-to-10 m depths <br />Fixed (ungimbaled) sensors<br />+ 10 vertical installation<br />60 mm OD sonde<br />3-and 6-component sensors<br />seismometers &/or accelerometers<br /> 2 Hz seismometers up to 500C<br /> MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 1950C<br />40 cm<br />
    11. 11. 1.iii Current standard instruments<br /> Deep – <br />“Observatory” – 1-to-5 km depths <br />Gimbaled sensors<br />90 mm OD sonde<br />+ 200 tilted borehole<br />3-and 6-component sondes<br />seismometers &/or accelerometers<br /> 2 Hz seismometers up to 500C<br /> MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 1950C<br />110 cm<br />
    12. 12. 1.iii Current standard instruments<br /> Multilevel – pipe installation<br />“Array” – 0-to-2 km depths <br />8-to-24 Fixed sensors<br />60 mm OD sonde<br />+ 900 tilted borehole<br />Passive 3-component sensors<br />seismometers<br /> 15 Hz seismometers to 800C<br />pipe<br />cable<br />sensorskid<br />recorder & boffins<br />cable & spool<br />
    13. 13. 1.iii Current standard instruments<br />Cableless – downhole recorder <br />“Autonomous” – 0-to-2 km depths <br />Gimbaled sensors + 24 bit 2 kHz recorder<br />110 mm OD sonde<br />+ 200 tilted borehole<br />3-and 6-component autonomous sondes<br />Seismometers/accelerometers/recorder<br />0.1 Hz enhance SM64 up to ?<br /> 2 Hz seismometers up to 500C<br /> MEMS accelerometers to 800C 4.5 & 15 Hz seismometers to 800C<br />Batteries<br />Recorder<br />Sensors<br />
    14. 14. Talk Outline<br />More Background: <br />Installation map<br />Observatory versus depth chart<br />Current standard seismographs<br />Motivation for borehole observatories <br />Detection<br />Location<br />Imaging<br />Research<br />Some Examples<br />Basel Switzerland<br />In progress – CAGS Donghai 5.2 km Observatory<br />
    15. 15. What happens to a seismic wave as it approaches the earth’s surface?<br />MEQ Recorded in 4.66 km stimulation Well – Basel <br />500 ms<br />Depth<br />4661 m<br />Basel1 C1<br />Basel1 C2<br />Basel1 C3<br />Basel1 C4<br />
    16. 16. Spectral analysis of Basel MEQ versus station<br />< 100 Hz<br />500 ms<br />2740 m<br />< 20 Hz<br />500 m<br />542 m<br />317 m<br />553 m<br />1213 m<br />
    17. 17. What happens to a seismic wave as it approaches the earth’s surface?<br />M ~ 0.5 MEQ Data from 3.3 km deep LVEW<br />see: http://quake.wr.usgs.gov/cgi-bin/heliexp.pl<br />Surface seismograph<br />Borehole seismograph<br />
    18. 18. SIGNAL REDUCTION BY INTRINSIC ATTENUATION<br />Borehole Seismic Array<br />Spectral Content as a function of depth - Note Log scales<br />0 m<br />100 m<br />200 m<br />300 m<br />400 m<br />>50 Hz<br />S <br />& <br />P<br />P<br />400<br />0<br />12.5 25 50 100<br /> Hz<br />25Hz<br />4<br />12.5 25 50 100<br /> Hz<br />>50 Hz<br />S<br />400<br />0/4<br />0<br />15Hz<br />12.5 25 50 100<br /> Hz<br />
    19. 19. . Event Detection – 3.3 km borehole in Mammoth CA <br />1 MIN<br />M~ 1 limit of ~ 15 station surface net <br />M~ -1 in 2.7 km observatory<br />M~ -2 in 2.7 km observatory<br />
    20. 20. Event Detection – 3.3 km borehole in Mammoth CA <br />
    21. 21. Net of Reasons 1 - 3: Signal-to-Noise Improvement with Depth & Signal Frequency<br />Depth<br />meters<br />1 Hz<br />10 Hz <br />100 Hz <br />1000 Hz<br />4096<br />+<br />+<br />2048<br />1024<br />512<br />256<br />128<br />64<br />32<br />16<br />Signal-to-Noise<br />4<br />loss due to scattering & attenuation <br />2<br />1<br />1<br />2<br />4<br />8<br />16<br />32<br />128<br />256<br />512<br />Signal to Noise Ratio<br />
    22. 22. The Gutenberg-Richter Relation.<br />1 MIN<br />M~ 1<br />M~ -1<br />LVEW December 2007 Seismicity on 2.7 km deep 4.5 Hz 3-component- sonde vertical channel. Analog chart display<br />
    23. 23. Detection & Location Improvement with Depth<br />?<br />?<br /> -2 -1 0 1 2 3<br /> Magnitude <br />
    24. 24. IMAGING OF SUBVERTICAL VELOCITY STRUCTURE & EVENT LOCATION!<br />
    25. 25. Depths vs. No. of Seismic Stations: Monitoring Objectives<br />Source Rupture Propagation<br />EQ Physics<br />Fault Structure<br />Statistics Locations Tomography <br />Seismotectonics<br />
    26. 26. Some Lessons Learned Along the Road to Seismology in the Source<br />Lesson I: How the road divides<br />Low RoadMiddle RoadHigh Road<br /> Inside casing wireline Inside casing wireline Outside casing tubing<br /> Few levels <10 Several Levels >10 Many Levels >100<br /> Digital component Digital component Digital component<br /> at surface at analog sensors Fully (e.g. MEMS)<br /> Analog components Analog components Analog components <br /> Armored Cu cables Hybrid OF to surface -<br /> Sensors Cu between levels<br /> No Power Power Power <br /> Low T & P Mid T & P High T & P <br /> < 100 C ~ 150 C > 150 C <br /> < 3 km ~ 3 km > 3 km<br /> Donated winch Used winch Special installation winch<br />Local Univ. & Industry Nat. Institutes & Industry Internat. Organ. & Industry <br />
    27. 27. Some Lessons Learned Along the Road to Seismology in the Source<br />Lesson II: The Do’s, Don’ts, and Maybe’s <br />Do’sMaybe’sDon’ts<br /> Triple fluid barriers Double fluid barriers Single fluid barrier <br /> Welded seals Metal-metal seals O-ring seals<br /> clamping/weight>>1 clamping/weight >1 clamping/weight ~1<br /> Passive clamps Hydraulic ram clamps Electrical ram clamps<br /> Passive TS Cu cable Single power cable Multiple power cable<br /> Armor+jacket+fill cable Jacket+fill cable jacket cable<br /> Passive sensors Low power sensors High power sensors<br /> electrically isolated case grounded case downhole ground<br /> for High T & P for Mid T & P for Low T & P <br /> > 150 C ~ 150 C < 100 C <br /> > 3 km ~ 3 km < 3 km<br /> Special winch Used winch Donated winch<br /> Internat. Institutes & Ind. Nat. Institutes & Industry Local Univ. & Industry<br />
    28. 28. ...and don’t forget the SAKE test...<br />
    29. 29. Talk Outline<br />More Background: <br />Installation map<br />Observatory versus depth chart<br />Current standard seismographs<br />Motivation for borehole observatories <br />Detection<br />Location<br />Imaging<br />Research<br />Some Examples<br />Basel Switzerland<br />In progress – CAGS Donghai 5.2 km Observatory<br />
    30. 30. With many thanks to the staff of Geopower Basel<br />BIG BOOM<br />IN<br />BASEL<br />The Big Boom in Basel or How Earthquakes (Nearly) Sank a Major EU Industry: Is Turkey Next?<br />Peter Malin, Eylon Shalev, and Dan Kahn<br />Institute of Earth Science and Engineering <br />University of Auckland, New Zealand <br />
    31. 31. BIG BOOM IN BASEL<br /> Induced Earthquakes and Geothermal in Downtown Basel, Switzerland<br />“Hot/Dry Rock” well<br />Basel from space<br />
    32. 32. The challenge at, for example, St Johann: Seismology and meat packing<br />
    33. 33. The challenge at, for example, St Johann: the Swiss rail service <br />
    34. 34. Serious Seismologist<br />MEMS Accelerometer<br />Gal’perin Seismometer<br />WeakLink<br />Fishing Tower<br />Signal Cable<br />Stress Member<br />
    35. 35. Railroad track<br />A typical 400 m installation: St. Johann<br />
    36. 36. OT-2 deep well: 2754 m 155º C<br />
    37. 37. Basel network<br />Map view N<br />Block view<br />Injection site<br />Injection site<br />OT-1<br />OT-1,2<br />OT-2<br />
    38. 38. BIG BOOM IN BASEL – the connection between earthquakes and fluid flow<br />Injection well<br />Microearthquakes<br />“Cementing” Microearthquakes<br />Injection well<br />MAP CROSS SECTION<br />
    39. 39. What happened?<br />December 2006<br />03 04 05 06 07 08 09 10 11 12 13 14<br />200<br />100<br />4<br />2<br />0<br />4<br />3<br />2<br />1<br />0<br />300<br />200<br />100<br />0<br />1 every 20 s<br />Water Pressure<br />bars<br />Number of event per hour:<br />Detected<br />Located<br />Magnitude<br />Magnitude<br />Legal Limit = 3.4<br />Legal Limit = 3.4<br />D J F M A M J J A S O N D J F<br />December 2006 – February 2008<br />
    40. 40. October 18, 2006 - 7:56 AM News<br />Swiss emergency officials have been participating in a huge earthquake preparedness exercise .......<br />.... disaster simulation coincides with the 650th anniversary of the <br />great Basel earthquake of October 18, 1356 – a 6.5 magnitude quake which destroyed most of the city.<br />
    41. 41. December 9, 2006 - 6:43 PM <br />Man-made tremor shakes Basel !<br />Drilling for a planned geothermal power plant triggered a small earthquake that caused minor damage to buildings.<br />......The Basel City prosecutor has launched an investigation to find if the company behind the Deep Heat Mining project should pay for repairs.....<br />Prosecution<br /> <br />.....The prosecutor's office launched its investigation on Friday evening. The police have already seized computer data....<br />
    42. 42. Hand over those earthquakes, you seismologist scum...<br />But sir!<br />I was just working on my PhD...<br />
    43. 43.
    44. 44.
    45. 45. The situation <br />downunder?<br />IESE <br />GEOPHONE<br />You said “stick’em up!”<br />Good heavens...I am borehole seismologist, not a social psychologist!<br />

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