HR: 0830h
AN: S11E-0338    [PDF]
TI: Volcano Monitoring with Coda Wave Interferometry at Mount Erebus, Antarctica
AU: * Gret, A
EM: agret@dix.mines.edu
AF: Dept. of Geophysics and Center for Wave Phenomena, Colorado School of mines 1500 Illinois str., Golden, CO 80401 United States
AU: Snieder, R
EM: rsnieder@mines.edu
AF: Dept. of Geophysics and Center for Wave Phenomena, Colorado School of mines 1500 Illinois str., Golden, CO 80401 United States
AU: Aster, R
EM: aster@dutchman.nmt.edu
AF: Dept Earth & Environmental Sci, New Mexico Inst Mining & Tech 801 Leroy Place, Socorro, NM 87801 United States
AB: Multiply-scattered waves dominate the late seismic coda. Small changes in the medium that would have no detectable influence on the first arrivals can be highly amplified by multiple scattering and readily observed in the coda. We apply coda wave interferometry to monitor subsurface temporal changes at Mount Erebus Volcano, Ross Island, Antarctica. Erebus is one of the few volcanoes known to have an open conduit system hosting a persistent convecting lava lake. Strombolian eruptions, caused by the explosive decompression of large bubbles of exsolved volatiles disrupt the lake itself, which subsequently refills within a few minutes. Because of the recoverability of this system, these eruptions provide a repeatable seismic source of seismic waves for sampling the strongly scattering volcano. Repeating eruption seismograms have been recorded at fixed station sites over several years, and the coda is seen to be highly reproducible over extended periods of time. We find waveform correlation coefficients as high as 0.98 for short-period seismograms recorded up to several days apart. However, in comparing seismograms separated by approximately a month, we note a small decrease in correlation. Furthermore, we see a much larger decorrelation of the waveforms spanning a time period of one or even two years. Coda energy is thus providing information on systematic source and/or subsurface changes.
DE: 1734 Seismology
DE: 8400 VOLCANOLOGY
SC: Seismology [S]
MN: 2003 Fall Meeting