Imaging Magma Transport During the 1997 Seismic Swarm off the Izu Peninsula, Japan
Yosuke Aoki,
12
Paul Segall,
1
Teruyuki Kato,
2
Peter Cervelli,
1
Seiichi Shimada
3
The spatio-temporal evolution of a propagating magma-filled crack
was estimated from inversion of Global Positioning System (GPS) data,
tiltmeters, and leveling. The dike opened at a maximum rate of 50 millimeters per day and had a peak magma flux of 2 × 106 cubic meters per day. Although the spatial resolution
was limited, slow upward propagation was resolved during the 9-day-long
intrusion. In contrast, the earthquakes migrated rapidly upward during
the first 12 hours of the swarm, and nearly all of the seismic energy was released in the first 2 days. Comparison of inversion results with
accurate hypocenter locations will lead to improved understanding of
magma transport through the brittle crust and of the causes of volcanic
seismicity.
1 Department of Geophysics, Stanford
University, Stanford, CA 94305-2215, USA.
2 Earthquake Research Institute, University of
Tokyo, 1-1, Yayoi 1, Bunkyo-ku, Tokyo 113-0032, Japan.
3 National Research Institute for Earth Science and
Disaster Prevention, 3-1, Tenno-dai, Tsukuba, Ibaraki 305-0006,
Japan.
