排序方式： 共有7条查询结果，搜索用时 15 毫秒
1
1.
2.
Anawat Suppasri Nobuo Shuto Fumihiko Imamura Shunichi Koshimura Erick Mas Ahmet Cevdet Yalciner 《Pure and Applied Geophysics》2013,170(6-8):993-1018
In 2011, Japan was hit by a tsunami that was generated by the greatest earthquake in its history. The first tsunami warning was announced 3 min after the earthquake, as is normal, but failed to estimate the actual tsunami height. Most of the structural countermeasures were not designed for the huge tsunami that was generated by the magnitude M = 9.0 earthquake; as a result, many were destroyed and did not stop the tsunami. These structures included breakwaters, seawalls, water gates, and control forests. In this paper we discuss the performance of these countermeasures, and the mechanisms by which they were damaged; we also discuss damage to residential houses, commercial and public buildings, and evacuation buildings. Some topics regarding tsunami awareness and mitigation are discussed. The failures of structural defenses are a reminder that structural (hard) measures alone were not sufficient to protect people and buildings from a major disaster such as this. These defenses might be able to reduce the impact but should be designed so that they can survive even if the tsunami flows over them. Coastal residents should also understand the function and limit of the hard measures. For this purpose, non-structural (soft) measures, for example experience and awareness, are very important for promoting rapid evacuation in the event of a tsunami. An adequate communication system for tsunami warning messages and more evacuation shelters with evacuation routes in good condition might support a safe evacuation process. The combination of both hard and soft measures is very important for reducing the loss caused by a major tsunami. This tsunami has taught us that natural disasters can occur repeatedly and that their scale is sometimes larger than expected. 相似文献
3.
Shunichi Koshimura Toshitaka Katada Harold O. Mofjeld Yoshiaki Kawata 《Natural Hazards》2006,39(2):265-274
This study develops a method for estimating the number of casualties that may occur while people evacuate from an inundation
zone when a tsunami has inundated an area. The method is based on a simple model of hydrodynamic forces as they affect the
human body. The method uses a Tsunami casualty index (TCI) computed at each grid point of a numerical tsunami model to determine
locations and times within the tsunami inundation zone where evacuation during the tsunami inundation is not possible and
therefore where casualties are likely to occur. The locations and times can be combined with information about population
density to compute the potential number of casualties. This information is useful in developing tsunami evacuation routes
that avoid such locations. To illustrate the method, it is applied to the Seattle waterfront in Washington State, USA, that
is under the threat of possible tsunami disasters due to Seattle Fault earthquakes. Preliminary results suggest that the tsunami
casualties may occur within the Seattle waterfront for 15 min, during the time interval from 3 to 18 min after a large Seattle
Fault tsunami is generated when the background tide level is mean high water. 相似文献
4.
Hideaki Yanagisawa Shunichi Koshimura Kazuhisa Goto Toyohiko Miyagi Fumihiko Imamura Anat Ruangrassamee Charlchai Tanavud 《Estuarine, Coastal and Shelf Science》2009
Using an integrated approach including satellite imagery analysis, field measurements, and numerical modeling, we investigated the damage to mangroves caused by the 2004 Indian Ocean tsunami at Pakarang Cape in Pang Nga Province, Thailand. Comparing pre- and post-tsunami satellite imagery of the study area, we found that approximately 70% of the mangrove forest was destroyed by the tsunami. Based on field observations, we found that the survival rate of mangroves increased with increasing stem diameter. Specifically, we found that 72% of Rhizophora trees with a 25–30 cm stem diameter survived the tsunami impact, whereas only 19% with a 15–20 cm stem diameter survived. We simulated the 2004 Indian Ocean tsunami using the nonlinear shallow-water wave theory to reproduce the tsunami inundation flow and investigated the bending moment acting on the mangrove trees. Results of the numerical model showed that the tsunami inundated areas along the mangrove creeks, and its current velocity reached 5.0 m s−1. Based on the field measurements and numerical results, we proposed a fragility function for mangroves, which is the relationship between the probability of damage and the bending stress caused by the maximum bending moment. We refined the numerical model to include the damage probability of mangrove forests using the obtained fragility function to investigate the tsunami reduction effect of mangrove forest. Under simple numerical conditions related to the mangrove forest, ground level, and incident wave, the model showed that a mangrove forest of Rhizophora sp. with a density of 0.2 trees m−2 and a stem diameter of 15 cm in a 400 m wide area can reduce the tsunami inundation depth by 30% when the incident wave is assumed to have a 3.0 m inundation depth and a wave period of 30 min at the shoreline. However, 50% of the mangrove forest is destroyed by a 4.5 m tsunami inundation depth, and most of the mangrove forest is destroyed by a tsunami inundation depth greater than 6 m. The reduction effect of tsunami inundation depth decreased when the tsunami inundation depth exceeded 3 m, and was mostly lost when the tsunami inundation depth exceeded 6 m. 相似文献
5.
Salinity in Soils and Tsunami Deposits in Areas Affected by the 2010 Chile and 2011 Japan Tsunamis 总被引：1，自引：0，他引：1
Takumi Yoshii Masahiro Imamura Masafumi Matsuyama Syunichi Koshimura Masashi Matsuoka Erick Mas Cesar Jimenez 《Pure and Applied Geophysics》2013,170(6-8):1047-1066
The accumulation of data sets of past tsunamis is the most basic but reliable way to prepare for future tsunamis because the frequency of tsunami occurrence and their magnitude can be estimated by historical records of tsunamis. Investigation of tsunami deposits preserved in geological layers is an effective measure to understand ancient tsunamis that occurred before historical records began. However, the areas containing tsunami deposits can be narrower than the area of tsunami inundation, thus resulting in underestimation of the magnitude of past tsunamis. A field survey was conducted after the 2010 Chile tsunami and 2011 Japan tsunami to investigate the chemical properties of the tsunami-inundated soil to examine the applicability of tsunami inundation surveys considering water-soluble salts in soil. The soil and tsunami deposits collected in the tsunami-inundated areas are rich in water-soluble ions (Na+, Mg2+, Cl?, Br? and SO 4 2? ) compared with the samples collected in the non-inundated areas. The analytical result that the ratios of Na+, Mg2+, Br? and SO 4 2? to Cl? are nearly the same in the tsunami deposits and in the tsunami-inundated soil suggests that the deposition of these ions resulting from the tsunami inundation does not depend on whether or not tsunami deposits exist. Discriminant analysis of the tsunami-inundated areas using the ion contents shows the high applicability of these ions to the detection of tsunami inundation during periods when the amount of rainfall is limited. To examine the applicability of this method to palaeotsunamis, the continuous monitoring of water-soluble ions in tsunami-inundated soil is needed as a future study. 相似文献
6.
7.
Characteristics of Tsunamis Propagating over Oceanic Ridges: Numerical Simulation of the 1996 Irian Jaya Earthquake Tsunami 总被引：1，自引：0，他引：1
The 1996 Irian Jaya earthquake tsunami was simulated by using the numerical model based on the linear long wave theory including Coriolis force in the spherical coordinate system. The numerical modeling result at Chichijima is in good agreement with the observed tide gauge data. The distinctive oscillation at Chichijima can be interpreted as the formation of boundary waves, so called ridge waves that are excited on the South-Honshu ridge. The mechanism of tsunami propagation trapped on an oceanic ridge is analyzed with the simple ridge model. The result explains the characteristics of ridge waves excited on theSouth-Honshu ridge. 相似文献
1