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Volume 58, Issue 2
Displaying 1-5 of 5 articles from this issue
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Kuniaki ABE2005 Volume 58 Issue 2 Pages 83-89
Published: September 30, 2005
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSWe observed seiches at 28 bays in Kii Peninsula, Japan, by the use of a pressure gauge and determined the dominant periods from the spectra. The spectra were extracted from time series of 1 minute sampling for 6 hours using Hanning window. Comparing the dominant periods with the maximum wave heights observed at the heads in the 1944 Tonankai tsunami and the 1960 Chilean tsunami, we obtained tsunami height dependence on the dominant period. Moreover, a tsunami height ratio, defined as a ratio of the maximum tsunami height at the head to that at the open coast, was plotted as a function of the dominant period. They showed the maximums at 12-25 and 31-60 minutes for the 1944 Tonankai tsunami and the 1960 Chilean tsunami, respectively. It was attributed to resonance of bays. At the resonance periods the height ratios are 2 for 1944 and 4 for 1960 tsunamis, respectively. The dominant periods, thus obtained, are useful as basic data for predicting tsunami amplifications of bays.View full abstractDownload PDF (1241K) -
Haruhiko SUZUKI, Michio MORINO, Koji IWAMOTO, YING Liu, Hiroyuki FUJIW ...2005 Volume 58 Issue 2 Pages 91-106
Published: September 30, 2005
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSBiwako-seigan fault zone is one of the most active faults in Japan, located around western shore of Lake Biwa. According to The Headquarters for Earthquake Research Promotion (2004), its probability of earthquake within 30 years is from 0.09% to 9%. To simulate strong motion, caused by the rupture of Biwako-seigan fault zone, we have constructed 3D subsurface structural model around Lake Biwa. The 3D subsurface structural model is constructed using the data of geophysical and geological surveys in and around Lake Biwa. We have modified the model by comparing the observed H/V spectral ratio between earthquakes and theoretical one. Using the modified 3D subsurface structural model, we simulated ground motions for moderate earthquakes. As the results, simulated waveforms of ground velocity agree well with observed ones. By the geological method and adjusting theoretical H/V spectral ratio to observed one, it is possible to re-construct 3D subsurface structural model which is applicable to strong motion simulation, even though there are few data of geophysical surveys.View full abstractDownload PDF (4019K) -
Kunikazu YOSHIDA, Tsutomu SASATANI2005 Volume 58 Issue 2 Pages 107-113
Published: September 30, 2005
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSDownload PDF (5067K) -
Mitsuharu UEDA, Hiroaki TAKAHASHI2005 Volume 58 Issue 2 Pages 115-119
Published: September 30, 2005
Released on J-STAGE: March 11, 2010
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Fumiko TAJIMA, Tomoeki NAKAKUKI, Shoichi YOSHIOKA2005 Volume 58 Issue 2 Pages 121-141
Published: September 30, 2005
Released on J-STAGE: March 11, 2010
JOURNAL FREE ACCESSNumerous seismological studies have presented models for the mantle structure associated with subducted slab. Variable slab behaviors revealed by recent 3D tomographic models, i. e., stagnation in the transition zone or penetration into the lower mantle before stagnation, stimulated debates as to the physical conditions to produce such different features. However, the causes of different slab behaviors yet remain unclear. While tomographic approaches are robust for visualizing the images of the Earth's deep interior, the gap between the conjecture based on large scale tomographic images and the reality of mantle property measurements in mineral physics is enormous. To reduce the gap, different approaches have been used such as regional body waveform modeling, numerical simulations of slab dynamics, or molecular dynamics simulations based on laboratory measured parameters of mantle properties. Here we review the recent development of the different approaches, and explore the issues for further studies.View full abstractDownload PDF (9961K)
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