HR: 0800h
AN: S51B-0155    [Abstracts]
TI: Understanding the Mechanism of Deep Earthquakes: A new System for Detecting Acoustic Emissions in Multianvil Experiments
AU: * Jung, H
EM: hjung@ucr.edu
AF: University of California, Institute of Geophysics and Planetary Physics, Riverside, CA 92521 United States
AU: * Jung, H
EM: hjung@ucr.edu
AF: Carnegie Institute of Washington, Geophysical Laboratory, Washington, DC 20015 United States
AU: * Jung, H
EM: hjung@ucr.edu
AF: Carnegie Institute of Washington, Department of Terrestrial Magnetism, Washington, DC 20015 United States
AU: Jiao, W
EM: wjiao@multimax.com
AF: Multimax Inc., 1441 McCormick Dr., Hyattsville, MD 20785 United States
AU: Fei, Y
EM: y.fei@gl.ciw.edu
AF: Carnegie Institute of Washington, Geophysical Laboratory, Washington, DC 20015 United States
AU: Silver, P G
EM: silver@dtm.ciw.edu
AF: Carnegie Institute of Washington, Department of Terrestrial Magnetism, Washington, DC 20015 United States
AU: Green, H W
EM: harry.green@ucr.edu
AF: University of California, Institute of Geophysics and Planetary Physics, Riverside, CA 92521 United States
AU: Green, H W
EM: harry.green@ucr.edu
AF: University of California, Department of Earth Sciences, Riverside, CA 92521 United States
AB: One of the major goals in the experimental study of deep earthquakes is to identify slip instabilities at high pressure and high temperature (HPHT) that might be responsible for earthquake occurrence. Detecting acoustic emissions from a specimen during faulting provides unique constraints on the instability process. There are few experimental studies reporting acoustic emissions under HPHT conditions, due to technical challenges. And those studies only used one or at most two acoustic sensors during the experiments. This precludes accurate location of the acoustic emission source region and thus the ability to distinguish real signal from noise that may be coming from outside the sample. We have developed a new system for detecting acoustic emissions at HPHT. Here we present a 4-channel acoustic emission detecting system working in the HPHT octahedral multianvil apparatus. Each channel has high resolution (12 bit) and a sampling rate of 30 MHz. In preliminary runs at pressures of 1 - 6 GPa and temperatures 300 - 1130 K, we have observed acoustic emissions. Analyzing these signals, we are able to show that this system permits us to distinguish between signal and noise, locate the source of the acoustic emission, and obtain reliable data on the radiation pattern. This system has greatly improved our ability to study faulting instabilities under high pressure and high temperature.
DE: 7230 Seismicity and seismotectonics
DE: 7294 Instruments and techniques
DE: 5102 Acoustic properties
DE: 7209 Earthquake dynamics and mechanics
DE: 1242 Seismic deformations (7205)
SC: Seismology [S]
MN: 2004 AGU Fall Meeting