HR: 1340h
AN: T23A-0566    [Abstracts]
TI: Temperature Measurements and Active Faulting
AU: * Mori, J
EM: mori@rcep.dpri.kyoto-u.ac.jp
AF: Disaster Prevention Research Institute, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AU: Ito, H
EM: hisao.itou@aist.go.jp
AF: Geological Survey of Japan, AIST, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8567 Japan
AB: Temperature measurements associated with active faults can be useful for studying the total energy balance, and especially the dynamic frictional levels during faulting of large earthquakes. However, temperature anomalies across faults or temperature changes associated with earthquakes are relatively rare. We make some simple calculations to estimate the temperature changes that should be observed across a fault for large earthquakes. For example, a temperature profile at 500 m depth across a fault that slipped 2 meters, at a time 6 months following the earthquake, shows a temperature anomaly of about 0.2 degrees, assuming an apparent coefficient of friction of 0.6. For an apparent coefficient of friction of 0.3, the anomaly reduces to about 0.05 degrees. The differences in the apparent coefficient of friction should be resolvable with the current temperature sensor instruments we are developing for borehole measurements. Estimating the apparent coefficient of friction is important for understanding the mechanics of faulting. The level of friction, and thus the amount of heat produced during an earthquake, has been a controversial issue in seismology for several decades. Timely measurements of the temperature profile across the fault following large earthquakes may be able to answer these long-standing questions about the level of dynamic friction.
DE: 8130 Heat generation and transport
DE: 8164 Stresses--crust and lithosphere
DE: 7209 Earthquake dynamics and mechanics
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting