Astronomy and Astrophysics – Astronomy
Scientific paper
Sep 2001
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001geoji.146..781t&link_type=abstract
Geophysical Journal International, Volume 146, Issue 3, pp. 781-794.
Astronomy and Astrophysics
Astronomy
6
Active Seismic Experiment, Attenuation, Autoregressive Model, Pipe-Like Structure, Pulse Width
Scientific paper
We estimate the P-wave velocity and attenuation structures beneath the Kirishima volcanic complex, southern Japan, by inverting the complex traveltimes (arrival times and pulse widths) of waveform data obtained during an active seismic experiment conducted in 1994. In this experiment, six 200-250kg shots were recorded at 163 temporary seismic stations deployed on the volcanic complex. We use first-arrival times for the shots, which were hand-measured interactively. The waveform data are Fourier transformed into the frequency domain and analysed using a new method based on autoregressive modelling of complex decaying oscillations in the frequency domain to determine pulse widths for the first-arrival phases. A non-linear inversion method is used to invert 893 first-arrival times and 325 pulse widths to estimate the velocity and attenuation structures of the volcanic complex. Wavefronts for the inversion are calculated with a finite difference method based on the Eikonal equation, which is well suited to estimating the complex traveltimes for the structures of the Kirishima volcano complex, where large structural heterogeneities are expected. The attenuation structure is derived using ray paths derived from the velocity structure. We obtain 3-D velocity and attenuation structures down to 1.5 and 0.5km below sea level, respectively. High-velocity pipe-like structures with correspondingly low attenuation are found under the summit craters. These pipe-like structures are interpreted as remnant conduits of solidified magma. No evidence of a shallow magma chamber is visible in the tomographic images.
Dawson Phillip B.
Kumagai Hiroyuki
Tomatsu Toshitaka
No associations
LandOfFree
Tomographic inversion of P-wave velocity and Q structures beneath the Kirishima volcanic complex, southern Japan, based on finite difference calculations of complex traveltimes does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Tomographic inversion of P-wave velocity and Q structures beneath the Kirishima volcanic complex, southern Japan, based on finite difference calculations of complex traveltimes, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Tomographic inversion of P-wave velocity and Q structures beneath the Kirishima volcanic complex, southern Japan, based on finite difference calculations of complex traveltimes will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1490017