|
Read Full Article (file size: 278546 bytes) Cited by
GEOPHYSICAL RESEARCH LETTERS,
VOL. 32,
L06304,
doi:10.1029/2004GL021143,
2005
Monitoring rapid temporal change in a volcano with coda wave interferometry
Alexander Grêt
Center for Wave Phenomena and Department of Geophysics, Colorado School of Mines, Golden, Colorado, USA
Roel Snieder
Center for Wave Phenomena and Department of Geophysics, Colorado School of Mines, Golden, Colorado, USA
Richard C. Aster
Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
Philip R. Kyle
Department of Earth and Environmental Science, New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
Abstract
Multiply–scattered waves typically dominate the late part of the seismic coda in local earthquake seismograms. Small medium
changes that have no detectable influence on the first arrivals are amplified by multiple scattering and may thus be readily
observed in the coda. We exploit this idea using Coda Wave Interferometry to monitor temporal changes at Mount Erebus Volcano,
Antarctica. Erebus is one of the few volcanoes on Earth with a long–lived convecting lava lake. Large exsolved gas bubbles
generate impulsive Strombolian explosions that provide a repeating seismic source of seismic energy propagating through the
strongly scattering geology of the volcano. We examined these signals during a particularly active eruptive two–month period
between December, 1999 and February, 2000. Early seismograms are highly reproducible throughout this period. During the first
month this is also the case for the coda. Approximately midway through this period, however, the seismic coda decorrelates
rapidly over a period of several days. This indicates a rapid change in the scattering properties of the volcano, likely reflecting
subtle changes in the near–summit magma/conduit system that would not be discernible using direct– or single–scattered seismic
wave methods.
Received 29
July
2004;
accepted 7
February
2005;
published 18
March
2005.
Index Terms: 0935 Exploration Geophysics: Seismic methods (3025, 7294); 5102 Physical Properties of Rocks: Acoustic properties.
Read Full Article (file size: 278546 bytes) Cited by
Citation: Grêt, A., R. Snieder, R. C. Aster, and P. R. Kyle
(2005),
Monitoring rapid temporal change in a volcano with coda wave interferometry,
Geophys. Res. Lett.,
32,
L06304,
doi:10.1029/2004GL021143.
Copyright 2005 by the American Geophysical Union.
|