Site-Specific Behavior of 2011 Tohoku Earthquake Tsunami Influenced by Artificial Changes of Coastal Environments

2012 ◽  
Vol 7 (sp) ◽  
pp. 485-490
Author(s):  
Chiharu Mizuki ◽  
◽  
Kazuomi Hirakawa ◽  
Keyword(s):  
Land Use ◽  
Pacific Coast ◽  
Tohoku Earthquake ◽  
2011 Tohoku Earthquake ◽  
Coastal Environments ◽  
Specific Behavior ◽  
The 2011 Tohoku Earthquake ◽  
Site Specific ◽  
The Pacific ◽  
Artificial Changes

Many aspects affect local tsunami behavior. A drastic change in behavior in the 2011 Tohoku Earthquake at specific sites in relation to coastal conditions in Hokkaido. These include coastal constructions such as jetty ports, digging formula ports, types of seawall, etc., in addition to land use for fisheries. Examples of site-specific behavior in the 2011 Tohoku Earthquake along the Pacific coast of Hokkaido are introduced in order to help future tsunami disasters.

Empirical Fragility Curves of Buildings in Northern Miyagi Prefecture During the 2011 off the Pacific Coast of Tohoku Earthquake

2016 ◽  
Vol 11 (6) ◽  
pp. 1253-1270 ◽  
Author(s):  
Hao Wu ◽  
◽  
Kazuaki Masaki ◽  
Kojiro Irikura ◽  
Susumu Kurahashi ◽  
...  
Keyword(s):  
Pacific Coast ◽  
Fragility Curves ◽  
Ground Motions ◽  
Strong Motion ◽  
Tohoku Earthquake ◽  
2011 Tohoku Earthquake ◽  
The 2011 Tohoku Earthquake ◽  
Kobe Earthquake ◽  
The Pacific ◽  
Miyagi Prefecture

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.

scholarly journals Evolution of the 2011 Tohoku Earthquake Tsunami on the Pacific Coast of Hokkaido

2012 ◽  
Vol 54 (1) ◽  
pp. 1250002-1-1250002-17 ◽  
Author(s):  
Yasunori Watanabe ◽  
Yuta Mitobe ◽  
Ayumi Saruwatari ◽  
Tomohito Yamada ◽  
Yasuo Niida
Keyword(s):  
Pacific Coast ◽  
Tohoku Earthquake ◽  
2011 Tohoku Earthquake ◽  
The 2011 Tohoku Earthquake ◽  
The Pacific

Postseismic Uplift Along the Pacific Coast of Tohoku and Kanto Districts Associated with the 2011 off the Pacific Coast of Tohoku Earthquake

2018 ◽  
Vol 13 (3) ◽  
pp. 496-502
Author(s):  
Takeshi Iinuma ◽  
Keyword(s):  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Fault Creep ◽  
The 2011 Tohoku Earthquake ◽  
Sanriku Coast ◽  
The Past ◽  
The Pacific ◽  
Kanto District ◽  
Coseismic Subsidence ◽  
Gps Observations

The 2011 off the Pacific coast of Tohoku earthquake (M9.0) produced up to 1.2 m subsidence along the Pacific coast in northeastern Japan. Based on Global Positioning System (GPS) observations, continuing postseismic coastal uplift has been detected in the past six years after the main shock. By applying a 3D spherical Earth viscoelastic finite element model using the postseismic seafloor and terrestrial GPS observations as constraints, I demonstrate that this uplift is mainly caused by the postseismic viscoelastic relaxation of the asthenosphere. Although the model was constrained only based on horizontal crustal deformation, the vertical displacements predicted for six years after the 2011 Tohoku earthquake agree reasonably well with the time series of the observed uplift at sites along the Pacific coast including the southern Sanriku coast and Kanto district. I estimated the time at which the cumulative postseismic uplift will fully compensate the coseismic subsidence. The results show that large coseismic coastal subsidence on the southern Sanriku coast will be fully offset by the postseismic uplift within several decades. To the immediate north, the model underpredicts the postseismic uplift and possibly indicates unaccounted postseismic fault creep. Farther south, the postseismic uplift of the coast of the Kanto district has already exceeded the small amount of coseismic subsidence over the past six years, as predicted by the model. To prepare for future earthquakes, especially with respect to the coastal construction at fishery ports, it is important to construct a comprehensive rheological structure model based on geophysical observations including GNSS positioning.

scholarly journals FIELD STUDY OF CONTRASTING BEACH RECOVERY PROCESSES OBSERVED IN NAMI-ITA and KIRIKIRI COASTS AFTER THE 2011 TOHOKU EARTHQUAKE

2018 ◽  
pp. 94
Author(s):  
Y. Kojima ◽  
Y. Tajima ◽  
Y. Matsuba ◽  
T. Shimozono ◽  
T. Terasawa ◽  
...  
Keyword(s):  
Field Study ◽  
Pacific Coast ◽  
Tohoku Earthquake ◽  
Shoreline Change ◽  
2011 Tohoku Earthquake ◽  
The 2011 Tohoku Earthquake ◽  
Shoreline Retreat ◽  
Recovery Processes ◽  
Northern Pacific ◽  
Pacific Coast Of Japan

The 2011 Tohoku Earthquake caused significant shoreline retreat along the northern Pacific coast of Japan and most of the affected beaches have not yet fully recovered even six years after the event. This study investigates overall characteristics of the shoreline change after the event and also investigates contrasting beach recovery processes observed in Nami-ita and Kirikiri coasts.

Damage Related to the 2011 Tohoku Earthquake in and Around Kamaishi City – Beyond the Tsunami Disaster –

2019 ◽  
Vol 14 (9) ◽  
pp. 1185-1200
Author(s):  
Tsuneo Ohsumi ◽  
Yuji Dohi ◽  
Hemanta Hazarika ◽  
◽  
Keyword(s):  
Coastal Area ◽  
Tohoku Earthquake ◽  
2011 Tohoku Earthquake ◽  
The South ◽  
The 2011 Tohoku Earthquake ◽  
Tsunami Disaster ◽  
South Central ◽  
The Pacific ◽  
Iwate Prefecture ◽  
Eastern Japan

Widespread damage was caused in eastern Japan as a result of the earthquake and tsunami which occurred in 2011 off the Pacific coast of Tohoku (hereinafter, the 2011 Tohoku Earthquake). A large tsunami struck the coastal area of eastern Japan and caused damage to buildings, breakwaters, tide embankments and river levees. The joint reconnaissance team of the Tohoku and Kyushu branches of the Japanese Geotechnical Society investigated the geotechnical damage in the south-central coastal area of Iwate Prefecture from the beginning of April to September 2011. This report summarizes the geotechnical hazards and the damage to port structures, roads, railways, river levees, and buildings caused by the earthquake motion and tsunami in the 2011 Tohoku Earthquake in the south-central coastal area of Iwate Prefecture. Major investigation areas are Kamaishi City (Koshirahama Port, Touni-Chou), the coastal area of Ofunato City (Sanriku-Chou Yoshihama, Sanriku-Chou Okirai), and Rikuzentakata City. In the 2011 Tohoku Earthquake, many people could not or did not evacuate from the tsunami. However, students at junior high and elementary schools started tsunami evacuation quickly, resulting in what is known as the “Kamaishi Miracle.” This study focused on the tsunami evacuation of children in Unosumai district, Kamaishi City.

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