著者

羽鳥 徳太郎

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.40, no.1, pp.1-6, 1987-03-25 (Released:2010-03-11)

参考文献数

13

被引用文献数

1

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Based on tide-gauge records, the Hyuganada tsunami of Aug. 7, 1984 is investigated. Adding the present data, the pattern of tsunami activity off the east coast of Kyushu since 1899 is discussed on a space-time diagram. The magnitude (Imamura-Iida scale) of the 1984 tsunami is estimated to be m=-1. This grade is small for an earthquake having magnitude of M=7.1. The source area of tsunami estimated by means of an inverse refraction diagram agrees with the aftershock area, and the source length is 25km in the N-S direction. The initial motion of the tsunami was in an upward direction at Hyuga-Shirahama, but at Tosa-Shimizu and Muroto, the initial disturbance began with a down motion. It suggests the west side of the sea-bottom uplifted and the east side subsided.According to the geographic distribution of the source area of the Hyuganada tsunamis generated during the last 86 years (1899-1984), the tsunami sources are parallel to the bathymetric line and their region is divided by three groups: A) is located near the Kyushu coast, B) about 50km east from the Kyushu coast and C) off the Shikoku coast. A tsunami of each group was generated on extension of the major axis of the former source. Tsunami magnitudes (Imamura-Iida scale, m=0-1.5) of the A and C groups are larger than that of the B group. From the pattern of generating cycle, the northern part of the A group is considered a region of relatively high tsunami risk as a type of the 1941 earthquake.

著者

羽鳥 徳太郎

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.48, no.1, pp.91-97, 1995-05-25 (Released:2010-03-11)

参考文献数

8

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Accompanied with the Guam earthquake on Aug. 8, 1993 (epicenter: 13.0°N, 144.7°E, d=61km, Ms=8.0, USGS), a tsunami was observed at many tidal stations in Japan. Tsunami magnitude and the behavior of propagation are investigated, comparing with those of the 1990 Saipan tsunami (m=2). The travel times in West Japan were about 3.5 hours. The maximum double amplitude at Muroto and Tosa-Shimizu near the tip of peninsula reached 84cm with the wave-period of 8 minutes, and those in the Ryukyu Islands were relatively small. The distribution pattan of wave-heights is similar to that of the 1990 Saipan tsunami. By judging from the diagram of the attenuation of wave-height with distance, the tsunami magnitude on the Imamura-Iida scale was determined to be m=2.5. Although wave-heights of the present tsunami are about 1.5 times higher than those of the 1990 Saipan tsunami, the magnitude value is normal compared to earthquake with similar size in other regions.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.58, no.3, pp.683-689, 1984-01-14

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著者

羽鳥 徳太郎

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.54, no.2, pp.p343-350, 1979

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著者

森本 良平 小坂 丈予 羽鳥 徳太郎 井筒屋 貞勝 浦部 和順 高橋 春男 岡田 義光 平林 順一 伊佐 喬三 磯部 宏

出版者

Tokyo Geographical Society

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.77, no.5, pp.255-283, 1968-10-25 (Released:2009-11-12)

参考文献数

25

被引用文献数

3 3

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Unusual uplift of the land was found about an insular active volcano Iwo-jima, Ogasawara archipelago, 1, 200 km south of Tokyo. Remarkable retreat of shore line was revealed by reviewing topographic maps and aerophotographs of the island. Some upward movements of the island are to be one of the most principal reasons of the retreat. As the clear evidences of the upheaval of the land, following phenomena were observed by the writers who investigated the island five times from 4th July to 23rd August 1968 : a) Sunken vessels and a landing craft have emerged on the western coastal beach of the island : b) Faults and cracks appeared on the abandoned run-way of the former Japanese Navy in the central part of the island ; c) Coastal reef emerged on the sea to connect off shore islet with the island ; d) New coastal terraces were formed on the sand beaches ; e) Fresh living corals were exposed on the sea.Results of the investigations are enumerated as follows : 1) About 8 m upheaval of the land since 1953-4 was revealed by levelling survey at the western coast of the island. 2) Amount of uplift observed on the above-mentioned run-way is smaller in its central part than in both terminals, maximum vertical displacement of the fault being 3 m. 3) Tide gauge installed at the western rocky coastrecorded slight relative down of sea level but further observation should be continued without disturbance by typhoon to obtain more reliable data. 4) No expected microseisms were recorded on the high sensitive electro-magnetic seismographs except 2 or 3 per day. 5) Temperature of the fumarolic gases were 95-123°C, 10-25°C higher than that observed in 1935. In spite of the rise in temperature, gases of so called high temperature type, such as sulphur dioxide and halogens, were not contained. 6) Composition of the sublimates also accords with these results of chemical analyses of the gases. 7) Content of each main component element and its ratio to other ones is quite variable in several hot springs whose pH values range from 2.1 to 6.8. 8) Analcite was identified by X-ray and DTA analyses in the tuff forming Moto-yama, an eastern main flat cone of the island. Genetic condition of the mineral inferred from its chemical composition may indicate submarine eruption of the volcano. 9) Three weak zones were recognized by the present investigations in addition to the two ones previously reported by Tsuya. Thus three are arranged radially through the center of the eastern main cone and the two are arranged concentrically around the foot of the same cone. From these weak zones phreatic explosions are expected in future, if they occur. 10) Nothing more than mere weak phreatic explosion was recorded through the historic activity of the volcano. Artificial filling up of the vent, such as the pavement of the surface often causes the small explosion at fumarole. 11) Submarine eruption recently found at the sea bottom, about 5.4 km NNE of the South Sulphur Island, about 50 km south of the island did not occur recently but must have repeated rather stationarily.According to the present investigations, no remarkable magmatic explosion could be expected except those small phreatic ones, same one of which has often occurred on the island. Chemical composition of the gases does not indicate any approach of hot magma to the surface.

著者

羽鳥 徳太郎

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.43, no.4, pp.773-782, 1966-03

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1965年2月4日05時01分21.8秒(GMT),アリューシャン列島中部に大地震が起こり,これに伴なつた津波は全太平洋に伝播し,北海道では地震後3時間30分して第1波を感じ,全日本太平洋岸で波高20~40cm(平常時の潮位上)の津波が観測された.U.S.C.G.S.の観測報告によれば震央は51.3°N,178.6゜E深さ40km,M=73/4(PAS,BEK)である.日本に伝播した津波について,気象庁,水路部,国土地理院から提供された検潮記録および,地震研究所で観測した宮城江ノ島,八丈島,伊豆大島,千葉県金谷の津波計記録を用い津波の概要を紹介し,二,三の考察を行なつた.

著者

羽鳥 徳太郎

出版者

公益社団法人 日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.51, no.2, pp.203-210, 1998-10-15

参考文献数

19

被引用文献数

1

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The generating frequency of the North-West American tsunamis is relatively lower than that of the South American region, but there are historical records of a large tsunami accompaning with the January 1700 earthquake (<i>M</i> 9) in the Cascadia subduction zone (SATAKE <i>et al.</i>, 1996). In the present paper, tsunami magnitudes on the Imamura-Iida scale, <i>m</i>, are investigated by using the diagram of wave-height attenuation with distance. The regional characteristics of tsunami magnitudes are discussed in relation to earthquake magnitudes, <i>M</i>_s, during the period from 1899 to 1997. The tsunami magnitudes in the South-East Alaska to Canada region are nearly normal compared to earthquakes with similar size in the other Pacific regions, and the 1899 Yakutat tsunami being <i>m</i>=3 is the largest. The magnitude values in the California region are mostly <i>m</i>=0 or less (amplitude: 50-100cm), but those of a few tsunamis vary by the faulting mechanism. For example, the magnitude value of the 1906 San Francisco tsunami accompaning with a strike-slip earthquake (<i>M</i>_s=8.3) is <i>m</i>=-4. On the contrary, that of the 1927 Lompoc tsunami caused by a high-angle thrust earthquake (<i>M</i>_s=7.0) is <i>m</i>=1, and this tsunami was observed in Hawaii and Japan. According to the epicenter distribution of the earthquakes (<i>M</i>_s&ge;6.5) since 1812, a seismic gap exists at the segment of 700km off the Washington to Oregon states. It should be considered a region of relatively high tsunami risk.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.58, no.2, pp.433-437, 1983-10-22

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1982年12月28日三宅島近海に発生した群発地震で,八丈島八重根検潮所において全振幅40cmの小津波が観測された.しかし,それ以外の伊豆諸島の検潮記録では風浪による顕著な副振動と重なり,津波は検知できなかった.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.60, no.1, pp.97-104, 1985-09-05

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小笠原父島における津波記録を収集し,その挙動を考察した.二見港の奥村では,1854年安政東海津波で集落の大部分が流失し,津波の高さは3~4mに達したとみなされる.また,1918年ウルップ(南千島)津波で全振幅2.7mを記録し,19戸が浸水被害を受けた.津波マグニチュード判定図によれば,父島ではフィリピン・ハワイなど南西・南東方向から入射する津波に対して,標準的な振幅で観測されている.しかし,日本近海でおきた津波では,いずれも顕著な波高になり,平均津波マグニチュードより1~1.5階級の偏差(エネルギーで5倍,波高にして2.3倍以上)がある.その要因のひとつとして,小笠原諸島は屈折効果で,津波エルギーが集まることが津波伝播図から認められた.東海地域の津波に対しては,さらに津波の指向性を強く受ける方向にあり,将来の東海地震においては津波に十分な警戒が必要である.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.61, no.1, pp.143-157, 1986-08-04

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秋田県南部の象潟・金浦海岸に顕著な地殻変動と地震・津波被害をもたらした文化元年(1804年)象潟地震について,新史料を加えて震度分布を調べ,地震の規模を検討した.一方,津波史料をもとに各地の津波の高さを現地調査し,津波の規模および発生機構を考察した.震度6の範囲が本荘~酒田間60kmに及んだことは,今村の報告(1921)と変わりはないが,震度4の地域は青森・宮城県および新潟県下にまたがつた.その広がりから地震のマグニチュードはM=7.3と推定される.海岸の地盤高をふまえて津波の被害状況をみると,津波の高さは象潟付近で平均海面上4~5m,酒田では3~4mと推定される.そのほか周辺の波高分布から判断すれば,津波マグニチュード(今村・飯田スケール)はm=1.5と格付けできる.震度・地殻変動の分布を考え合せると,波源域の長径は本荘~酒田沿岸南北方向に,60kmと推定される.津波の規模は地震の規模に対して標準以上に大きく,この津波は高角の逆断層で起こされたものと考えられる.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.54, no.3, pp.543-557, 1980-03-31

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Adding tsunami data reported by the U.S.S.R. sources, tsunami magnitude and the source area of the tsunamis generated in the Hokkaido and Kurile regions during the period from 1893 to 1978 are re-examined. The source dimension and magnitude of the tsunamis generated in the Hokkaido region correspords well with the earthquake magnitude. However, the tsunamis in the Kurile region have varied behaviors. The two Kurile tsunamis of Oct. 20, 1963 and June 10, 1975 were especially abnormal in comparison with other tsunamis accompanied by similar earthquake magnitude. In most cases, the initial motion of the tsunamis was observed with upward direction, but the Kurile tsunamis of Aug. 11, 1969 and June 10, 1975 began with a conspicuous downward motion at the Hokkaido and Kurile tide stations. The source areas of the tsunamis that accompanied large earthquakes (M>8) line up along the continental slope near the Kurile trench and the 1973 Nemuro-oki tsunami was generated in the seismic gap between the 1952 Tokachi-oki and the 1969 Shikotan earthquakes. However, the source area of the 1973 tsunami occupies only the eastern half of the 1894 tsunami source. After the 1973 Nemuro-oki tsunami, the tsunami activity moves to the northeastern direction along the Kurile trench. These source areas fall in the southern part of the source areas of the 1958 Iturup and the 1969 Shikotan tsunamis. In the space-time diagram of the earthquakes having a magnitude of M≧7, remarkable gaps can be seen in the west side of the 1973 tsunami source and off Urup Island. It is possible that a future tsunami of magnitude m~2 may be generated, accompanying the release of seismic energy in the two regions.

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.53, no.3, pp.855-861, 1978-12-25

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.57, no.3, pp.525-535, 1983-01-17

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A small tsunami was generated by the Urakawa-oki earthquake (M=7.1) near Cape Erimo, southern Hokkaido, on March 21, 1982. At Urakawa, the initial disturbance of the present tsunami began with an upward motion simultaneous with the earthquake occurrence. The first wave period was 16min and the third wave was the highest with a semi-amplitude of 80 cm. According to the author's method based on the attenuation of wave-amplitude with distance, the tsunami magnitude (Imamura-Iida scale) are estimated to be m = 0. This rank is average for an earthquake having a magnitude of M=7.1. The source area of the present tsunami which inferred from an inverse refraction diagram is located along the coast from Urakawa to Shizunai. The length of the tsunami source is 40 km and the width 20 km. The tsunami source area agrees with the aftershock area. From the analysis of the initial tsunami motion on the records, an average uplift of 14 cm may have occurred at the sea-bottom of the source area.

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

羽鳥 徳太郎 片山 通子

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.52, no.1, pp.49-70, 1977-11-30

著者

羽鳥 徳太郎

出版者

東京大学地震研究所

雑誌

東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo (ISSN:00408972)

巻号頁・発行日

vol.61, no.2, pp.329-338, 1986-12-10

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ソ連沿海州・北朝鮮および韓国沿岸からの津波伝播図を作図し,1983年日本海中部地震津波において,波源から射出された津波が大陸から反射して日本沿岸に到達する時間を調べた.そして各地で観測された検潮記録の波形との対応を検証した.その結果,発震時から2~5時間の間に,各地で顕著な振幅が発現した時刻が,大陸からの反射波の到達時間と±10分以内で合致しており,積丹半島・能登半島周辺および山陰地方に,波向線が集まることが認められた.将来,日本海に発生する津波の予報にあたっては,大陸からの反射波の動向も注目する必要がある.

著者

羽鳥 徳太郎

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.58, no.3, pp.683-689, 1984-01-14

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熱海・初島において,1923年関東地震津波について,地震体験者の住民から聞きとり調査を行った.熱海では当時の海岸から約200m,地盤高がT.P.上7m以下の市街地に浸水したことが分った.熱海中心部の海岸では津波の高さは7.0~8.0mと推定される.一方,初島では地盤が隆起して集落内に津波は侵入せず,津波の高さは1.8m程度であった.

著者

羽鳥 徳太郎

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.3, pp.p423-431, 1984

被引用文献数

3

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新史料を加え,天保14年(1843年)北海道東部津波の挙動を検討した.浸水被害状況から,津波の高さは厚岸4~5m,白糠3~3.5m,函館0.5m,八戸2.5~3mと推定され,津波マグニチュードはm=2.5とみなせる.近年の十勝沖・根室沖津波と比べると,震度・波高分布は1952年十勝沖津波のものと同様なパターンを示し,波源域は十勝沖にあった可能性が大きい.With the addition of new data on the East Hokkaido tsunami of Apr. 25, 1843 (Tenpo 14), the inundation heights along the Hokkaido and Sanriku coasts are investigated. According to the old documents, 75 houses were washed away and 45 persons drowned at Akkeshi, East Hokkaido. Several houses were damaged at Hachinohe, and 46 persons drowned at Taro on the Sanriku coast. The estimated inundation heights (above mean sea-level) are 4-5m at Akkeshi, 3-3.5m at Shiranuka, 0.5m at Hakodate, and 2.5-3m at Hachinohe. The tsunami magnitude (Imamura-Iida scale) seems to be m=2.5. Distribution patterns of the seismic intensity and inundation height in the Hokkaido and Tohoku regions are very similar to those of the 1952 Tokachi-oki tsunami (m=2.5). The source area of the 1843 tsunami may be located off the Tokachi coast along the west side of the 1894 Nemuro-oki tsunami (m=2). A segment of about 100km in the Tokachi region should be considered a relatively high tsunami risk area.

著者

羽鳥 徳太郎

出版者

歴史地震研究会

雑誌

歴史地震 (ISSN:13499890)

巻号頁・発行日

no.25, pp.75-80, 2010

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.