著者

相田 勇 梶浦 欣二郎 羽鳥 徳太郎 桃井 高夫

出版者

東京大学地震研究所

雑誌

地震研究所研究速報

巻号頁・発行日

vol.8, pp.58-62, 1964-09

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昭和39年6月16日新潟地震調査概報

著者

相田 勇 羽鳥 徳太郎 村井 勇 広井 脩

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.59, no.2, pp.p235-265, 1984

被引用文献数

1

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1983年日本海中部地震の際に発令された津波警報に対する,新潟県村上市の自治体当局や住民の反応について,その実態の調査を行った.海岸地域の867世帯に対してアンケート調査を行った結果,53%がすぐにも津波がくると思ったと答えており,テレビなどの情報に注意したり,海を見にいくなど外の様子に注意した人は,ともに63%程度に達している.この段階で自主的に実際に避難したとする回答は,35件,5.4%あり,この地域では,地震があれば津波の用心をするという意識はかなり高い.この意識は,1964年新潟津波の被害程度に明らかな相関が認められた.津波警報は一般に高く信用されているが,来襲津波の程度の判断などは,自分自身の過去の経験にもとついている.また津波来襲は警報発令後40分以上経過していたにもかかわらず,その段階で警報を知らなかった人がほぼ20%程度あった.これは警報伝達の方法に問題を投げかけている.船舶の処置については,地震後,直ちに行っている率がかなり高く,小舟をおかに上げたもの41.4%,10~49トンの船で港外へ避難したもの26.7%である.警報が出ると更に多くなって,小舟のおかへ上げたもの52.4%,10~49トンの船で港外へ避難したもの58.3%となっている.このため漁船の被害は生じなかった.This is the research conducted at Murakami City in Niigata Prefecture to investi gate the social responses to the tsunami warning issued immediately after the 1983 Nihonkai-Chubu earthquake. We interviewed the officials of the local administrative organs and sent written questionnaires to 867 households in the seaside districts. We received replies from 75 percent of them. The results of the research are as given below. Owing to a false report in the course of disseminating the warning, the transmission through the administrative organs was delayed. But many people spontaneously took special care about the tsunami. More than half the people paid attention to the television broadcast, or carefully watched the state of the sea. And 5.4 percent of the people took refuge in some safe place. Such cautious behavior by the people is clearly correlated with the degree of damage which they suffered from the 1964 Niigata tsunami. The tsunami hit the Murakami seashore more than 40 minutes after the warning was issued. But even then 20 percent of the inhabitants did not know the warning had been issued. This means that it is necessary to establish and rearrange the warning dissemination system to the residents. There were two ways of dealing with ships when people heard the warning ; one was to leave the harbor, the other was to beach the ships. In this earthquake, most people managed to take care of their ships properly, although a number of pleasure-boats moored near the river bank were capsized.

著者

羽鳥 徳太郎 相田 勇 岩崎 伸一 日比谷 紀之

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.56, no.1, pp.245-263, 1981-08-31

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Owase located on the east side of Kii Peninsula has been hit by many tsunamis. Sources of most tsunamis were off Tokaido along the Nankai Trough. The 1960 Chile tsunami that propagated across the Pacific Ocean also hit Owase City. There remain even now traces of the inundated level on many houses in Owase caused by the 1944 Tonankai and 1960 Chile tsunamis. Based on these traces, the inundation heights of the two tsunamis run-up on land were surveyed, using the automatic level from Nov. 4 to 7, 1980. The relation between the geographical distribution of the inundation heights and the damage to houses was investigated. The results of the present surveys are as follows: 1) The inundation heights of the 1944 Tonankai tsunami at the harbor were 5.0-5.5 m above M.S.L. Ground about 3.0 m above M.S.L. was inundated. The inundated area stretched along the Kita River. The water level decreased in height as it moved inland. The topography of the ground controls the damage to houses. Fifty percent of the ordinary Japanese wooden type houses were damaged when the water reached 1.5 m above the ground. From the inclination of the water surface along the Kita River, the mean water velocity is calculated as 3.5 m/sec. 2) The inundation heights of the 1960 Chile tsunami at the harbor were 3.0-3.5 m above M.S.L. Although the water reached 1.0-1.5 m above the ground, hardly any houses were washed away. The traces of the inundated level into land are nearly flat, suggesting that the velocity of the incident flow was small. 3) Based on old documents, the inundation height of the Ansei Tokai tsunami (Dec. 23, 1854) is estimated as 6.5 m above M. S. L. The heignt is 0.7-1 m higher than that of the 1944 Tonankai tsunami. Ground above 4 m high was inundated.

著者

相田 勇 梶浦 欣二郎 羽鳥 徳太郎 桃井 高夫

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.42, no.4, pp.741-780, 1965-03-15

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A tsunami accompanying the Niigata Earthquake of June 16, 1964 is described on the basis of mareograms collected in the vicinity of the source area and a field survey, carriedout immediately after the earthquake by the members of the Earthquake Research Institute, along the coast of the Japan Sea from Akita to Naoetsu. The generating area of the tsunami, estimated by means of an inverse travel chart of the wave front based on the arrival time of the initial motion of the tsunami to the coastal station, is located in the sea on the continental shelf, extending about 90km in an elongated shape roughly parallel to the coast line from the northern part of Niigata Prefecture to Yamagata Prefecture.

著者

相田 勇

出版者

公益社団法人 日本地震学会

雑誌

地震 第2輯 (ISSN:00371114)

巻号頁・発行日

vol.49, no.1, pp.55-63, 1996-05-24 (Released:2010-03-11)

参考文献数

14

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Edo (now Tokyo) area suffered serious damage from a great earthquake in 1855, Ansei era. The earthquake is conceived to be essencially an inland earthquake, although the crustal movement might be extended to the bottom of Tokyo Bay. Whether or not a tsunami was generated by the earthquake is investigated basing on historical documents. Although, no tsunami damage was reported, it seems likely that some phenomena associated with a tsunami, which was too small to be observed obviously, took place. Numerical experiments on three fault models, that are supposed on the upper surface of the subducted Philippine sea plate, are made in order to see possible tsunami generation in Tokyo Bay. Maximum double amplitudes of computed tsunamis amount to 10 to 20cm which are in harmony with historical documents. It may be one of the reasonable interpretations for the source model of the earthquake, therefore, that the Ansei Edo earthquake occurred on the plate boundary. Water oscillations induced by the seismic acceleration in a tank or a pool are numerically investigated. It becomes apparent that such water oscillation is largely controlled by the resonance in the reservoir.

著者

相田 勇

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.47, no.4, pp.673-700, 1969-09

被引用文献数

1

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The present work is an attempt to approach the problem of tsunami propagation by means of a numerical experiment. A preliminary experiment to examine the computing accuracy has been carried out for the square origin in a uniform water depth with a sufficient performance. The Niigata tsunami was treated, because the submarine crustal movement in the tsunami origin had been surveyed in detail. The experimental results were satisfactory in the comparison of the wave forms with two tide gage records and also in the comparison of profile of the maximum water elevation with the actual inundation height. The energy radiation pattern of the wave origin itself shows the directivity of such a shape as an Arabic numeral, 8, however, the actual tsunami radiates the strong energy toward the coast but the weak energy seaward. It is understood that this is caused by a refraction of wave on the sloping shelf. As for the Tokachi-oki tsunami, several models of wave origin were assumed for experiments. By comparing the computed result with tide gage records, the most probable model was selected.|日本近海の津波波源から海岸までの津波伝播の問題は,種々興味あるところであるが,今まで実験的に取扱つた例はなかつた.ここでは,数値実験の方法でこの問題を取扱つた.方法は,基礎微分方程式を差分方程式に変換し,計算格子上の各点の水位分布,流量分布を交互に計算する通常の方法である.予備実験として,正方形波源が,一定水深の海にある場合について行ない,格子間隔の疎い場合,細かい場合の比較を行なつた.続いて新潟津波について,水路部で測られた波源附近の海底の変動が瞬間的に起つたものとして,日本海岸の各地に到達する津波を求めた.検潮記録との比較で,実験波形はかなりよく一致し,また全体の波高分布も実測とよく一致する.波源自身のエネルギー放射の指向性についても調べたが,波源は8字形の指向性を持つている.実際には陸側にのみ強い指向性を示し,沖には非常に弱くなる.これは陸棚傾斜によるものと解される.十勝沖津波について数個の波源モデルが仮定され,それぞれについて実験が行なわれた.各地の検潮記録と比較した結果,最も適当と思われるモデルが求められた.それによると,波源域の北西隅に沈降地域があつて,沈降と上昇地域の境界は,ほぼ143°Eの線の上にある,隆起量の最大は約5m位である,などが推定される.

著者

羽鳥 徳太郎 相田 勇 岩崎 伸一 日比谷 紀之

出版者

東京大学地震研究所

雑誌

東京大学地震研究所彙報 (ISSN:00408972)

巻号頁・発行日

vol.56, no.1, pp.p245-263, 1981

被引用文献数

1

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Owase located on the east side of Kii Peninsula has been hit by many tsunamis. Sources of most tsunamis were off Tokaido along the Nankai Trough. The 1960 Chile tsunami that propagated across the Pacific Ocean also hit Owase City. There remain even now traces of the inundated level on many houses in Owase caused by the 1944 Tonankai and 1960 Chile tsunamis. Based on these traces, the inundation heights of the two tsunamis run-up on land were surveyed, using the automatic level from Nov. 4 to 7, 1980. The relation between the geographical distribution of the inundation heights and the damage to houses was investigated. The results of the present surveys are as follows: 1) The inundation heights of the 1944 Tonankai tsunami at the harbor were 5.0-5.5 m above M.S.L. Ground about 3.0 m above M.S.L. was inundated. The inundated area stretched along the Kita River. The water level decreased in height as it moved inland. The topography of the ground controls the damage to houses. Fifty percent of the ordinary Japanese wooden type houses were damaged when the water reached 1.5 m above the ground. From the inclination of the water surface along the Kita River, the mean water velocity is calculated as 3.5 m/sec. 2) The inundation heights of the 1960 Chile tsunami at the harbor were 3.0-3.5 m above M.S.L. Although the water reached 1.0-1.5 m above the ground, hardly any houses were washed away. The traces of the inundated level into land are nearly flat, suggesting that the velocity of the incident flow was small. 3) Based on old documents, the inundation height of the Ansei Tokai tsunami (Dec. 23, 1854) is estimated as 6.5 m above M. S. L. The heignt is 0.7-1 m higher than that of the 1944 Tonankai tsunami. Ground above 4 m high was inundated.