Yuichiro Tanioka 교수

Tsunami generation by an earthquake is generally modeled by water surface displacement identical to the vertical deformation of ocean bottom due to faulting. The effect of horizontal deformation is usually neglected. However, when the tsunami source is on a steep slope and the horizontal displacement is large relative to the vertical displacement, the effect becomes significant. We show this for two recent earthquakes which generated much larger tsunamis than expected from seismic waves. In the

The June 15, 1896 Sanriku earthquake generated devastating tsunamis with the maximum run‐up of 25 m and caused the worst tsunami disaster in the history of Japan, despite its moderate surface wave magnitude (M s =7.2) and weak seismic intensity. This is a typical tsunami earthquake, which generates anomalously larger tsunamis than expected from its seismic waves. Previously proposed mechanisms of tsunami earthquakes include submarine slumping and slow rupture in the accretionary wedge or in the

The 1896 Sanriku earthquake was one of the most devastating tsunami earthquakes, which generated an anomalously larger tsunami than expected from its seismic waves. Previous studies indicate that the earthquake occurred beneath the accretionary wedge near the trench axis. It was pointed out recently that sediments near a toe of an inner trench slope with a large horizontal movement due to the earthquake might have caused an additional uplift. In this paper, the effect of the additional uplift to

Coseismic slip distribution on the fault plane of the 1944 Tonankai earthquake is estimated from inversion of tsunami waveforms. Three improvements from a previous study [ Satake, 1993] are made. These are: (1) smaller subfaults are used to resolve detailed slip distribution; (2) the sub faults fit better to the plate interface geometry; and (3) finer and more accurate bathymetry data is used. The inversion result shows that a maximum slip of about 3 m occurred on the plate interface off Shima p

Abstract The lateral (along trench axis) variation in the mode of large earthquake occurrence near the northern Japan Trench is explained by the variation in surface roughness of the subducting plate. The surface roughness of the ocean bottom near the trench is well correlated with the large‐earthquake occurrence. The region where the ocean bottom is smooth is correlated with‘typical’large underthrust earthquakes (e.g. the 1968 Tokachioki event) in the deeper part of the seismogenic plate interf

Abstract Rupture process of the 2004 Sumatra-Andaman earthquake is estimated using tsunami waveforms observed at tide gauges and the coseismic vertical deformation observed along the coast. The average rupture speed of the 2004 Sumatra-Andaman earthquake is estimated to be 1.7 km/s from tsunami waveform analysis. The rupture extends about 1200 km toward north-northwest along the Andaman trough. The largest slip of 23 m is estimated on the plate interface off the northwest coast in the Aceh provi

Coseismic slip distribution on the fault plane of the 1946 Nankai earthquake (Mw 8.3) was estimated from inversion of tsunami waveforms. The following three improvements from the previous study (Satake, 1993) were made. (1) Larger number of smaller subfaults is used; (2) the subfaults fit better to the slab geometry; and (3) more detailed bathymetry data are used. The inversion result shows that the agreement between observed and synthetic waveforms is greatly improved from the previous study. I

The fault geometry and slip distribution of the Hokkaido Nansei‐oki, Japan, earthquake of July 12, 1993 are estimated using seismic wave, tsunami, and geodetic data. The Moment Tensor Rate Function inversion from P waves shows one nodal plane shallowly dipping to the west and the other nodal plane steeply dipping to the east. The best depth is estimated as 10–15 km. The source time history consists of an initial pulse with a duration of 10 s and moment release of 2 × 10 20 Nm, followed by a comp

The slip distribution of the 2003 Tokachi-oki earthquake is estimated from the 11 tsunami waveforms recorded at 9 tide gauges in the southern Hokkaido and eastern Tohoku coasts and two ocean bottom tsunami-meters (pressure gauges) off Kamaishi, Tohoku. The largest slip of 4.3 m is estimated on the subfault located off Hiroo. A large slip of 2.1 m is also estimated on the subfault located near Kushiro. The total seismic moment of the 2003 Tokachi-oki earthquake is 1.0 × 1021 Nm. The slip distribu

Tsunami height survey was conducted immediately after the 2003 Tokachi-oki earthquake. Results of the survey show that the largest tsunami height was 4 m to the east of Cape Erimo, around Bansei-onsen, and locally at Mabiro. The results also show that the tsunami height distribution of the 2003 Tokachi-oki earthquake is clearly different from that of the 1952 Tokachi-oki earthquake, suggesting the different source areas of the 1952 and 2003 Tokachioki earthquakes. Numerical simulation of tsunami

Abstract A large eruption of the Hunga Tonga-Hunga Haʻapai volcano in Tonga on January 15, 2022 generated air–sea coupled tsunamis observed at the ocean-bottom pressure sensor network along the Japan Trench (S-net) in Japan. Initial tsunamis from the 2022 Tonga eruption, detected by 106 ocean-bottom pressure sensors, were well modeled by an air–sea coupled tsunami simulation, with a simple atmospheric pressure pulse as sine function, having a half-wavelength of 300 km and a peak amplitude of 2 h

Research Article| May 01, 1997 Source Time Functions Yuichiro Tanioka; Yuichiro Tanioka University of Michigan Department of Geological Sciences 425 E. University Ann Arbor, MI 48109-1063 Search for other works by this author on: GSW Google Scholar Larry J. Ruff Larry J. Ruff University of Michigan Department of Geological Sciences 425 E. University Ann Arbor, MI 48109-1063 Search for other works by this author on: GSW Google Scholar Seismological Research Letters (1997) 68 (3): 386–400. https:/

The fault geometry, depth, and slip distribution of the Kurile earthquake of Oct. 4, 1994 are estimated using seismic waveforms, aftershock distribution, geodetic measurements, and tsunami waveforms. Previous large earthquakes in the Kurile arc had typical underthrusting focal mechanisms due to the local subduction. Seismic wave inversions of the 1994 event indicate a thrust type mechanism with a large strike‐slip component. This does not represent an underthrust event at the subduction interfac

Fault geometry, depth, and slip distribution of the Sanriku‐oki earthquake of December 28, 1994 (Ms 7.5) are estimated from seismic waveforms, geodetic measurements, and tsunami waveforms, and compared with those of the 1968 Tokachi‐oki earthquake (Mw 8.2), the most recent large earthquake in the epicentral region. Seismic wave inversions indicate a shallowly dipping thrust type mechanism and the focal depth of 22–28 km, representing an underthrust event at the subduction interface. The source t

The tsunami generated by the 1998 Papua New Guinea earthquake was observed at several tide gauges and ocean bottom pressure gauges in Japan. The fault model of the 1998 Papua New Guinea earthquake was estimated using those tsunami waveforms observed in Japan and coseismic subsidence observed along the coast of Papua New Guinea near the source region. The numerical simulation of the tsunami using the linear Boussinesq equation was carried out. The tsunami waveforms in Japan are explained by the f