Astronomy and Astrophysics – Astronomy
Scientific paper
Aug 2000
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2000geoji.142..361s&link_type=abstract
Geophysical Journal International, Volume 142, Issue 2, pp. 361-370.
Astronomy and Astrophysics
Astronomy
3
Clvd (Compensated Linear Vector Dipole) Earthquake, Ocean Bottom Seismology, T Phase, Volcanic Activity
Scientific paper
On 1996 September 4, a submarine earthquake occurred underneath the Smith Caldera near Tori-Shima on the Izu-Bonin arc, Japan. Its mechanism was a CLVD with the principal tensile dipole in the vertical direction. The tsunami magnitude Mt of 7.5 was significantly larger than not only the body wave magnitude, mb, of 5.6 but also the moment magnitude, Mw, of 5.7, and thus slow faulting is not a major cause of the generation of large tsunamis. We have detected successive T-wave trains subsequent to the direct T-wave train from this earthquake on the records of the OBS submarine cable arrays off northeastern, central and southwestern Honshu. We have located these T-wave origins to be coincident with the epicentre of the CLVD earthquake within their solution errors. The T-wave events were repeated for about 35min, while their wave characteristics changed with time. The T-wave amplitude at a station about 700m deep increases with time more strongly than those at stations at greater depths. The T-wave duration is shortened progressively with time. The spectral shape of these T waves is similar to that for ordinary shallow earthquakes, indicating that the ultimate origins of these T waves are within the solid Earth rather than at or above the ocean bottom. Such temporal changes and the spectral shape suggest that the origins of these T waves are seismic shocks that migrated upwards well into the body of the Smith Volcano. The spectra of seismic waves from the CLVD source lack significantly high-frequency components, suggesting a lower than normal rupture velocity due presumably to a hotter source environment than in the surrounding region. We suggest that as a result of the CLVD earthquake, the magma-bearing source material was squeezed radially inwards and expelled vertically outwards to induce the magma ascent and associated upward migration of seismic events.
Fukao Yoshio
Kanazawa Toshihiko
Kanjo Kenji
Sugioka Hiroko
No associations
LandOfFree
Volcanic events associated with an enigmatic submarine earthquake 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 Volcanic events associated with an enigmatic submarine earthquake, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Volcanic events associated with an enigmatic submarine earthquake will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-737977