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Temperature Measurements in ~ 1 km Borehole of TCDP. Jim Mori, Yasuyuki Kano, Takeshi Yanagidani DPRI Kyoto Univ. Hisao Ito JAMSTEC. Taiwan Chelungpu Fault Drilling Project - TCDP.
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Temperature Measurements in ~ 1 km Borehole of TCDP Jim Mori, Yasuyuki Kano, Takeshi Yanagidani DPRI Kyoto Univ. Hisao Ito JAMSTEC
Taiwan Chelungpu Fault Drilling Project - TCDP Taiwan Chelungpu Fault Drilling Project - TCDP
Quartz Oscillator Thermometer and Pressure Sensor resolution 0.001 oC
Temperature Measurements March 2005
Platinum Resistance Temperature Detector Resolution 0.003 oC
Temperature Stabilization of Borehole May 18 July 2
Temperature Measurements lowering 1.0 m/min raising 0.4 m/min
Results Kano et al., 2006
Results Temperature signal very small ! ・ Heat is very small ・ Dynamic friction level is very small (smaller than standard rock mechanics values) ・ Important for dynamic friction mechanisms
Problems Temperature is close to noise level Effect of water flow ? Depth dependent values of heat capacity ? => Need measurements soon after earthquake
Need for Quick Measurement 1 year after earthquake 6 year after earthquake
Platinum Resistance Thermistors Resolution 0.001 oC
Temperature Stabilization • - Noise Level
Conclusions - Very low values of heat measured at 1 km depth after 6 years at TCDP - Takes about 120 days for temperature to stabilize after drilling - Noise levels in temperature measurements are about 0.01 oC - Want repeated time measurements over months to years
Installing Temperature Sensor in Chelungpu Fault, Taiwan (March 2005)
(Officer, 1974) S = Strength of heat source/area a = heat diffusivity Used Grid Search to find S and a Plane Heat Source = S
2005 Temperature Measurements t=1.2 MPa u = 5 meters fault displacement c = 1140 J/(Kg oC) specific heat ρ = 2500 Kg/m3 density m= 0.08 sn = lithostatic stress at 325 m sp = 1/3 * sn
Effect of Water Flow Kano et al., 2006
Resolution of quartz wt. length, diameter, resol resolution of pressure sensor hakkin -name, resolution Figure of time for 1 km hole and 300 km Speed of temperature measurements Photo of hakkin Photos of new sensor, what kind ? resolution