Risk Evaluation of Drifting Ship by Tsunami

2013 ◽  
Vol 8 (4) ◽  
pp. 573-583 ◽  
Author(s):  
Yusuke Suga ◽  
◽  
Shunichi Koshimura ◽  
Ei-ichi Kobayashi ◽  
◽  
...  

Drifting ship due to tsunami inundation flow may cause additional damage in harbor area. Many drifting ships were found in the 2011 Great East Japan earthquake tsunami and these caused various problems (damage of ships themselves, striking other structures and obstacle for restoration). In this sense, it is very important for disaster prevention to predict the drifting motion of a large ship by tsunami current. This study aims to simulate the drifting motion of ships by the 2011 Tohoku earthquake tsunami in Kesennuma harbor, Miyagi Prefecture. First, we simulated the hydrodynamic features of the 2011 tsunami by numerical simulation. Secondly, we analyzed the drifting motion of large ships using the result of tsunami numerical simulation. In the analysis, several test cases were conducted by changing parameter and initial position of the ship. Then we verified the results of the ship drifting simulation by comparing with actual grounding position of ships. Throughout the comparisons and verifications, we found the grounding position by the simulation was generally consistent with actual position of ships. Although it is necessary to verify the drifting route of ships, the results suggest that this model is beneficial for future disaster prevention.

2012 ◽  
Vol 7 (sp) ◽  
pp. 476-484 ◽  
Author(s):  
Takaaki Uda ◽  
◽  
Kazuya Sakai ◽  
Yukiyoshi Hoshigami ◽  
Yasuhito Noshi ◽  
...  

The massive earthquake with a magnitude of 9.0 occurred at 14:46 on March 11, 2011, with an epicenter 130 km offshore from the Oshika Peninsula in Japan’s northeastern Miyagi Prefecture. After the earthquake, large tsunamis were generated owing to abrupt crustal subsidence and uplift, which inundated Japan’s eastern Pacific Ocean coastline. We carried out field observations to investigate the deformation of a previous river-mouth bar by comparing oblique photographs, and investigated the damage to seawalls and the tsunami inundation depth on the Iwama-Sanuka coast, located north of the Same River in southern Fukushima Prefecture. Here, the results of the field observations on the deformation of the sandy beach and the inundation of the Iwama-Sanuka coast are reported.


Author(s):  
Takuya Miyashita ◽  
Nobuhito Mori

The inundation of the 2011 Tohoku Earthquake Tsunami showed complex behavior over the land. According to the surveys of the Tohoku Earthquake Tsunami in 2011, the behavior of tsunami in urban areas was different from that in rural areas and the damage was not only dependent on the inundation heights but also the local momentum. The buildings are commonly excluded and smoothed off in the topography in the conventional inundation simulation but it’s important to understand the local characteristics of tsunami run-up in urban areas. The purpose of this study is to understand and validate numerical models of tsunami in the urban area.


2016 ◽  
Vol 11 (6) ◽  
pp. 1253-1270 ◽  
Author(s):  
Hao Wu ◽  
◽  
Kazuaki Masaki ◽  
Kojiro Irikura ◽  
Susumu Kurahashi ◽  
...  

In this study, empirical fragility curves expressed in terms of relationship between damage ratio indices of buildings and ground motion indices were developed in northern Miyagi prefecture located in near-field areas during the 2011 off the Pacific coast of Tohoku Earthquake. The ground motion indices were evaluated from observed ground motions at strong-motion stations and estimated at sites at which no strong-motion accelerometers were deployed during the mainshock. The ground motions at the non-instrumental sites were estimated using the empirical Green’s function method based on bedrock motions inverted from observed records on surfaces from small events that occurred inside the source fault, transfer functions due to underground velocity structures identified from microtremor H/V spectral ratios, and a short-period source model of the mainshock. The findings indicated that the empirical fragility curves as functions of Japan Meteorological Agency (JMA) instrumental seismic intensity during the 2011 Tohoku Earthquake almost corresponded to those during the 1995 Kobe Earthquake and the seven disastrous earthquakes that occurred between 2003 and 2008. However, the empirical fragility curves as functions of peak ground velocity were the lowest. A possible reason for this is that the response spectra of the ground motions in the period ranging from 1.0 s to 1.5 s were small during the 2011 Tohoku Earthquake. Another reason could be the seismic resistant capacities of buildings in the studied districts involved during the 2011 Tohoku Earthquake exceeded those in the cities affected during the 1995 Kobe Earthquake.


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