Magmatic dike resonances inferred from very-long-period seismic signals.
Very-long-period (VLP) signals showing simple decaying harmonic oscillations with periods near 10 seconds and lasting for about 300 seconds were observed in association with an earthquake swarm that occurred beneath Hachijo Island, Japan. Results from the source-mechanism analysis and waveform simulation based on a fluid-filled crack model consistently point to the resonance of a dike filled with a basaltic magma as the source of the VLP signals. Thus, VLP signals can be used to probe the state of the fluid and dynamic processes within a volcanic system.
Kumagai
Hiroyuki
H
National Research Institute for Earth Science and Disaster Prevention, Tsukuba, Japan. kumagai@bosai.go.jp
Miyakawa
Koji
K
Negishi
Hiroaki
H
Inoue
Hiroshi
H
Obara
Kazushige
K
Suetsugu
Daisuke
D