Yoshihiro Kase - Academia.edu (original) (raw)

Papers by Yoshihiro Kase

Japan Geoscience Union, Mar 10, 2016

Pure and Applied Geophysics

The Hyuga-nada region is located in the southwestern part of the Nankai Trough in the Pacific Oce... more The Hyuga-nada region is located in the southwestern part of the Nankai Trough in the Pacific Ocean, where M7 class interplate earthquakes have been repeatedly occurring because of the subduction of the Philippine Sea Plate. The largest earthquake recorded in history for the Hyuga-nada region was the Hyuga-nada earthquake of 1662, which occurred off Miyazaki Prefecture in the southeastern area of Kyushu region, Japan, generating a tsunami. The region is also an area where slow earthquakes are active at the shallow part of the plate boundary. It is confirmed by the 2011 Tohoku earthquake that the active area of shallow slow earthquakes also became a tsunami source area. We hypothesize that the unusually large tsunami of 1662 was caused by the coseismic slipping of the active source area of shallow slow earthquakes. We constructed the fault model of the 1662 Hyuga-nada earthquake based on recent geophysical observations. A numerical simulation of the tsunami was carried out using the ...

Japan Geoscience Union, Mar 14, 2019

Annual Meeting of the Geological Society of Japan, 2017

Annual Meeting of the Geological Society of Japan, 2018

Annual Meeting of the Geological Society of Japan, 2016

Digital electronic technology is an engineering professional course, a solid foundation for learn... more Digital electronic technology is an engineering professional course, a solid foundation for learning, improve the students' practical ability. According to the digital electronic technology experimental teaching reform and exploration of the existing problems, project driven teaching method was proposed in digital electronic technology training, the idea of project teaching and implementation method. Through the combination of software simulation and hardware experiment, we study the curriculum reform from three aspects: teaching methods, teaching methods and laboratory management.

高の妥当性仁科健二・川上源太郎・廣瀬亘・渡邊達也・加瀬善洋・石丸聡・大津直・鈴木隆広・田村慎・輿水健一・高橋良(北海道立総合研究機構地質研究所)・田近淳(株式会社ドーコン) A... more 高の妥当性仁科健二・川上源太郎・廣瀬亘・渡邊達也・加瀬善洋・石丸聡・大津直・鈴木隆広・田村慎・輿水健一・高橋良(北海道立総合研究機構地質研究所)・田近淳(株式会社ドーコン) Assessment the appropriateness of estimated tsunami scale evaluated on height of event deposit along the Okhotsk Sea coast of northeast Hokkaido Kenji Nishina, Gentaro Kawakami, Wataru Hirose, Tatsuya Watanabe, Yoshihiro Kase, Satoshi Isimaru, Sunao Ohtsu, Tahahiro Suzuki, Makoto Tamura, Ken’ichi Koshimizu, Ryo Takahashi (Hokkaido Research Organization, Geological survey of Hokkaido) and Jun Tajika (Docon Co., Ltd)

Hyuga-nada region is located at the south-western part of Nankai Trough, in the Pacific Ocean. M7... more Hyuga-nada region is located at the south-western part of Nankai Trough, in the Pacific Ocean. M7-class interplate earthquakes are repeatedly occurred by the subducting Philippine Sea plate beneath the Eurasian plate. The largest earthquake in this area was the 1662 Hyuga-nada earthquake (M=7.6) which occurred off Miyazaki Prefecture, south-eastern area of Kyushu region, Japan, and generated tsunami (after called the 1662 tsunami). Strong ground motion hit and many structures were broken near the coast of Miyazaki Prefecture. The tsunami heights were estimated at least 4-5 m along the coast of Miyazaki city, and more than 200 people died by the earthquake and tsunami by historical records. This region is also active area of the shallow slow earthquakes. The 1662 tsunami was much larger than tsunamis generated by usual M7-class interplate earthquakes. It is known by the 2011 Tohoku earthquake that focal area of shallow slow earthquakes also become a tsunami source area. So, we hypoth...

Japan Geoscience Union, 2017

The 1741 tsunami was generated by the Oshima-Oshima sector collapse in the southwestern Hokkaido,... more The 1741 tsunami was generated by the Oshima-Oshima sector collapse in the southwestern Hokkaido, Japan. The tsunami caused great damage along the coast of Japan Sea in Oshima and Tsugaru peninsula. By the survey of tsunami deposits, at the coast of Okushiri Island and Hiyama in Hokkaido, tsunami deposits of this tsunami were found. In this study, the landslide and tsunami by the Oshima-Oshima eruption were modeled to explain distribution of debris deposits, tsunami heights by historical records, and distribution of tsunami deposits. First, region of landslide and debris deposits were made out from the bathymetry based on the bathymetry survey data (Satake and Kato, 2001) in the north part of Oshima-Oshima. In addition, topography before the sector collapse and landslide volume were re-estimated. The volume of landslide was estimated at 2.2 km. Based on those data, the landslide and tsunami were simulated using the integrated model of landslide and tsunami considered soil mass and w...

The 1662 Hyuga-nada Earthquake is one of the largest earthquakes to have occurred in the Hyuga-na... more The 1662 Hyuga-nada Earthquake is one of the largest earthquakes to have occurred in the Hyuga-nada region, Southwest Japan, rupturing the western part of the Nankai Trough subduction zone. Strong ground motion and a large tsunami with an estimated height of at least 4–5 m were reported along the coast of Miyazaki Prefecture, Kyushu Island, with extensive damage reported across this region. Therefore, developing a more complete picture of the 1662 Hyuga-nada Earthquake will improve our understanding of tsunami risk along the Pacific coast of Southwest Japan. Here we use the most recent geophysical data from the region to propose a novel source model for the 1662 Hyuga-nada Earthquake that incorporates our current understanding of the interactions between slow earthquakes and great earthquakes. The source area in our proposed model extends from the focal region of recurrent M7-class interplate earthquakes to the region of slow earthquakes that occur at relatively shallow depths along...

The eastern margin of the Japan Sea is located along an active convergent boundary between the No... more The eastern margin of the Japan Sea is located along an active convergent boundary between the North American and Eurasian tectonic plates. Okushiri Island, which is situated off the southwest coast of Hokkaido, is located in an active tectonic zone where many active submarine faults are distributed. Studying the records of past tsunamis on Okushiri Island is important for reconstructing the history and frequency of fault activity in this region, as well as the history of tsunamis in the northern part of the eastern margin of the Japan Sea. Five tsunami deposit horizons have been identified previously on Okushiri Island, including that of the 1741 tsunami, which are interbedded in the coastal lowlands and Holocene terraces. However, these known tsunami deposits date back only ~3,000 years. A much longer record of tsunami occurrence is required to consider the frequency of submarine fault activity. In this study, we cored from 7 to 25 m depth in the Wasabiyachi lowland on the souther...

Journal of the Sedimentological Society of Japan, 2017

The Journal of the Geological Society of Japan, 2018

The Journal of the Geological Society of Japan, 2017

Extensive research has been conducted on tsunamigenic deposits along the eastern margin of the Ja... more Extensive research has been conducted on tsunamigenic deposits along the eastern margin of the Japan Sea since the Tohoku Earthquake and tsunami. This paper reviews the characteristics of the large known tsunamis and the possible tsunamigenic deposits identified in this region. We have also reconstructed the spatio-temporal distribution, and a provisional correlation, of the tsunamigenic deposits in order to estimate the tsunami recurrence intervals and their wave source regions. Most of the tsunamigenic deposits were recognized in peaty and marshy deposits found on swales of coastal dunes, flood plains, and small valley plains. Large numbers of tsunamigenic sandy layers were also identified in lagoonal deposits. In addition, some gravelly deposits of possible tsunamigenic were recognized on top of low-lying marine terraces and slope talus. Although several historical tsunamis in the-th centuries have been recorded along the eastern margin of the Japan Sea, there are few localities where deposits can be correlated to these records. Tsunamigenic deposits suggest that four tsunami events have occurred during the-th centuries, despite there being limited historical records of tsunamis older than the th century. The distribution of these four deposits is as follows: th century = Aomori-northern Yamagata; th century = southwestern Hokkaido; th century (? AD) = Sado/Niigata-southern Yamagata; th century (? AD) = (Sado)-Yamagata-Aomori. These events are also recorded in the deep-sea Japan Basin as seismo-turbidites. Most tsunamigenic deposits older than the th century have only been identified at remote islands (Okushiri, Tobishima, and Sado). Several unanswered research questions on these tsunamigenic deposits remain, such as robust identification of the origins and precise ages of the deposits. Our work provides a framework for future screening of potential tsunamigenic deposit data and an improved understanding of paleotsunami events along the eastern margin of the Japan Sea.