著者

村井 勇 松田 時彦 中村 一明

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.53, no.3, pp.995-1024, 1978-12-25

著者

松田 時彦 山崎 晴雄 中田 高 今泉 俊文

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.55, no.3, pp.795-855, 1981-03-07

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The Rikuu earthquake (M = 7. 2) occurred in the Mahiru Mountains in Tohoku district on 31 August 1896. Associated with the earthquake, reverse faults appeared on the surface along the western and the eastern feet of the Mahiru Mountains (Table 1 and Fig. 1), which are known as Senya and Kawafune earthquake faults (YAMASAKI, 1896), respectively. This was the largest on-land surface faulting of reverse fault type among events in historical time in Japan. These surface faults were re-studied.

著者

松田 時彦

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.40, no.2, pp.357-369, 1962-11-15

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In this paper the crustal structure of the South Fossa Magna region, where a Tertiary geosyncline is developed, is inferred geologically under some assumptions. The method here adopted consists of two steps; 1) preparation of the stratigraphic profiles in every stage of geological devolopment of the region, and 2) modification of the stratigraphic profiles by the subsequent deformation of the crust. 1) Preparation of the stratigraphic profiles. The early Miocene Misaka and the middle to late Miocene Fujikawa series are the main conponents of the nearsurface crust of the region. They vary in thickness in different geological provinces in the region. Their geologic and tectonic maps are shown in Figs. 1 and 2. The pre-Misaka sediments are supposed geologically to have been deposited on the oceanic crust of transitional crust between the main Japanese Islands and the Pacific. These data and assumptions as well as those listed in A) of Table 2 are used for the stratigraphic profiles of the region (Fig. 3). 2) Modification of the stratigraphic profiles. After the deposition of the Misaka series, the following events took place: i) crustal warping with deposition of the Fujikawa series in the downwarping parts and with erosion of the Misaka series in the upwarping parts, ii) intrusions of quartz diorite stocks of the uplifted parts, and iii) formation of the crystalline schist along the southern limb of the Tanzawa upwarping part. (Boulders of the quartz diorite and of the crystalline schists appear in the upper part of the Fujikawa series of the subsiding belts). Until the end of the deposition of the Fujikawa series, the crustal surface was de- formed in a wavy contour as shown in curve s-s of Fig. 4. From the observations of the Tanzawa schist belt, we can assume that the wavy deformation of the crust mentioned above is due to shear fold with the shear plane inclined northward with angle about 70°. Then we get curve b-b in Fig. 4 as the bottom of the crust. Besides, it is assumed that the quartz diorite magma originated due to melting of the crust and the Mohodiscontinuity represents a boundary between two different materials (the basaltic and ultramafic), and that the volume change of the crust through the magmatic process which brought the quartz diorite stocks and through other tectonic process is negligible. Thus, we get Fig. 5 (b) as the crustal structure of the South Fossa Magna at the end of the Fujikawa time. Fig. 5(b) is here proposed as the present status of the region. If the method and data used in this paper are adequate, it is suggested that present Moho-discontinuity lies between the -15 to -20 km level with increasing depth northward. The Moho-discontinuity shows a fairly strong relief (10 km or more), whose troughs and swells correspond to the subsided belts and uplifted belts originated in Miocene. It is also suggested from Figs. 3 and 5 that the quartz diorite magma was generated from the lower crust in 15 to 20 km depth in the orogenetic epoch. The heat sufficient to melt the crust at such a shallow level might have been supplied from the mantle below.

著者

松田 時彦

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.45, no.2, pp.537-550, 1967-08-25

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松代地震の進展につれて松代町東部に地震断層の性格をもつた横ずれ地割れ群があらわれたので,その地割れ付近および周辺山地の地質を調べた. 1.調査地域内には,変位量数km以上の既存の大断層は存在しない.とくに今回あらわれた横ずれ地割れ群に沿つては,変位量数m程度の既存の小断層も見出せなかつた. 2.今回の地震であらわれた個々の地割れに沿つても,また,地割れ地帯に沿つても,最近地質時代に同様の変位が生じた形跡(地形的証拠)は見出されない. 3.鮮新世中期以降変位したことのない地質断層(滝本東断層)が地割れ帯に近接して存在するが,それに沿つては今回の地震で地割れは1つもあらわれなかった. 4.既存の断層に沿つて,断層性の変位が生じたたしかな例が1つだけみつかつたが,その断層は主な地割れ地帯からはなれているし,断層面のむきも変位のむきも特異である.松代地震における上記1.と2.の事実は,濃尾・北伊豆などの大地震に伴なつた地震断層の場合と全く異なつている.その意味で松代地震では従来いわれたような「古傷(大地質断層)の再活動」という表現は妥当でない.このような特異性と,松代地震が群発型であることを組合せると,大きな活断層が発達しない所(地質区)では群発地震の方が非群発型大地震よりもおこり易いらしいといえる.上記3の事実は,たとえ大断層があつても最近地質時代(この場合鮮新世中期以後)に変位を増加させた形跡のない断層は,今回のような地震の発生やそれに伴う変位に関与しないらしいという例になる.上記4の地震断層は,松代地震による直接の地震断層ではなくて,その周辺に生じた地盤の調整的変位の結果または地塊縁辺部での強い地震動の結果,地塊境界で生じた二次的変位(いわば間接的地震断層)であると思われる.

著者

森本 良平 村井 勇 松田 時彦 中村 一明 恒石 幸正 吉田 鎮男

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.44, no.1, pp.423-445, 1966-07-25

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Geology of the main seismic area in and around the town of Matsushiro, the northern part of Nagano Prefecture, central Japan, is investigated by field and literature surveys for the better understanding of the earthquake-swarm which is now taking place. The Matsushiro earthquake-swarm started at the beginning of August, 1965. Since then, the local seismicity has become more active with occasional rise and fall.

著者

松田 時彦 有山 智雄

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.60, no.2, pp.281-316, 1985-11-08

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1984年9月14日の長野県西部地震に伴って,震央の北西約5kmの御岳山の南斜面が崩壊して岩屑流が発生した.その堆積物に対する観察結果を記述した.岩屑流はi)空気を媒質としたなだれ状の流れであった,ii)流下時に王滝川合流点付近より上流では強風を伴い岩屑をしぶき状に周辺にはねとばした("岩屑しぶき").iii)堆積物は中・上流部では地形の小起伏に無関係にうすく平行堆積しているが,下流部(堆積域)では,低所にむかって再移勤している.iv)この岩屑流の直後に山体から噴出した地下水によって水を媒質とした土石流が発生した.

著者

松田 時彦 太田 陽子 岡田 篤正 清水 文健 東郷 正美

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.52, no.3/4, pp.461-496, 1978-03-31

著者

佐山 守 河角 広

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.10, no.2, pp.1-50, 1973-03

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When a big earthquake occurs, the en quete method through post cards is usually carried out for the inverstigation of intensity distribution and damage and their relations to the ground conditions and geology. Thus collected data isalsousefulforthe prevention of damage due to big earthquakes. This method can be applied to large historical earthquakes when abundant historical documents are found. As the first step of the application of on qttete method to historical earthquakes, the Zenkoji earthquake which occurred at about 10 p.m. on the 24th of March, 1847 was studied.

著者

河角 広

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 (ISSN:00408972)

巻号頁・発行日

vol.30, no.4, pp.319-323, 1952-01-30

著者

河角 広

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 (ISSN:00408972)

巻号頁・発行日

vol.30, no.4, pp.325-330, 1952-01-30

著者

野口 和子 中村 操 津村 建四朗

出版者

東京大学地震研究所

雑誌

東京大学地震研究所技術研究報告 (ISSN:13426486)

巻号頁・発行日

no.13, pp.147-162, 2007

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

高橋 龍太郎 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.39, no.3, pp.561-577, 1961-12-15

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At 3 h 10m 59.1s (J.S.T.), Feb. 27, 1961, there occurred a remstrong earthquake off the south-east coast of Kyushu, Japan. According to the Japan Meteorological Agency (JMA), the magnitude of the earthquake was 7.2, depth 17km and the position of the epicenter 31°.7 N, 131°.7E. Accompanying this earthquake, a moderate tsunami was observed on the coasts of Kyushu and Shikoku.

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

羽鳥 徳太郎 小山 盛雄

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.49, no.1/3, pp.127-142, 1971-09-30

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For the tsunamis which were generated off the Pacific coast of Japan during the last 76 years (1894-1969), the tsunami travel times observed at 12 tide stations are listed in Table 1. Features of the frequency distribution of travel time for NE Japan are different from those for SW Japan, because of the difference of the geographic characteristics of the tsunami source (Fig. 1). In the former region, a large frequency is found in the range of 30~40min, in contrast to 10~20m in the latter region. Starting from 19 tide stations indicated in Fig. 2, the inverse refraction diagrams of long waves are drawn on bathymetric charts (Figs. 3-12). Wave fronts are shown at 2min intervals. The uncertainty of the diagrams may be within ±2min for most of the regions considered.

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.723-734, 1984-01-14

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多数の検潮記録を用い,日本海中部地震による津波の波源域,規模などを調査した.波源域は水深2,000mの海域を中心に,津軽・男鹿沖間長さ140km,幅90kmと推定される.津波マグニチュードは,Δ-H曲線からm=2.5と格付けされる.日本海全域の津波伝播図を示し,伝播についての特徴を述べた.また,歴史津波を加え,日本海側でおきた津波の波源域分布を示し,波源域の配列・津波の空白域などを考察した.

著者

高橋 龍太郎 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.40, no.4, pp.873-883, 1963-03-10

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1. There are many theoretical studies on the generation of gravity waves due to an initial surface elevation or to a surface impulse. As to model experiments, however, very few studies have been made on this subject. Recent investigations of after-shocks and the propagation of tsunami waves have revealed that most of the generating area of a tsunami seems to be strongly elliptical in shape. The present experiment has been undertaken to clarify experimentally the characteristics of waves generated by a sudden dislocation of the bottom of elliptic shape. The experiment was carried out in a model basin (25m×40m×0.6m), in Chiba Prefecture, belonging to the Earthquake Research Institute. (Fig. 19). 2. The wave generator is an iron box, 94 cm × 56 cm × 4 cm in size, placed at the bottom level of the basin. It has an elliptic opening on the top covered with a rubber membrane, 2 mm thick, 90 cm × 30 cm (Fig. 20). This elliptic rubber membrane is made to swell out suddenly by compressed air as shown in Figs. 1 and 21. The wave-height gauge is of the parallel-wire type, consisting of 2 stainless steel triangular plates (Fig. 2). The sensitivity of the recorder is such that a deflection of 10mm on the record corresponds to 5.0mm in the water level change. No remarkable effect of capillarity exists in the records. The wave-heights were recorded by a 12-channel portable optical oscillograph. Eleven wave-height gauges were used, the remaining channel of the oscillograph being reserved for recording the motion of the center of the rubber membrane. The oscillograph chart was driven at a speed of either 10 or 30 mm/sec. 3. Records of waves due to the upheaval of the membrane were obtained at every foot from the center of the origin up to 4m and for a water depth of 5.0 cm and 17.3 cm. Details of experimental runs are shown in Table 1 and Fig. 5. A record in Fig. 6 shows the displacement of the center of the rubber membrane when the paper speed is 100 mm/sec. The time of the displacement was fixed at about 1/40 sec for all runs in the experiments. Figs. 7 and 8 show the final forms of the rubber membrane when expanded under certain pressures. Forms may be considered to be nearly a part of a paraboloid. 4. Figs. 22 and 23 are wave-height records for the water depths of 5.0 cm and 17.3 cm respectively. In these records, Nos. 1, 2 and 7 show wave-heights, respectively, just above the center of the origin and at the ends of the short and long axes of the elliptic rubber membrane. No. 12 is a record of the displacement of the centre of the origin. The front of a wave train is propagated roughly with the velocity √gh, except in the immediate neighbourhood of the origin, where a considerably larger velocity is observed. (Fig. 9) Wave trains have a dispersive character as shown in Fig. 11. 5. The initial surface elevation of water above the origin is about half of the displacement of the bottom itself. (Fig. 12). The ratio of the wave-heights at the ends of the long and short axes of the origin area is one-third, but for the positions distant from the origin, this ratio decreases. This result is interesting because the height ratio coincides with the length ratio of the elliptical axes (Fig. 13). The amplitude of an initial crest seems to decrease as r-0.5 and r-0.74 when the depths are 5.0cm and 17.3cm respectively (Fig. 14). Energy of the long-wave can be expressed as follows: E∝rη2L r: distance, η: wave-height, L: length of wave. Then we have EB/EA=(ηB/ηA)2 LB/LA EA, ηA and LA are energy, wave-height and wave length respectively along the long axis. EB, ηB and LB are corresponding quantities along the short axis. At the elliptic margin of the origin we have ηb/ηa = 3, Lb/La = 0.42, therefore Eb/Ea = 3.8, in the case of a water depth of 5 cm. For the distances 1m ≧ r ≧ 4m ηB/ηA = 1.8, LB/LA = 0.40, EB/EA = 1.3 Fig. 16 shows the azimuthal distribution of energy obtained by Run 8. The relation between the wave-length of the waves emitted into a certain direction and the radius of the ellipse in that direction seems to indicate that these two lengths are roughly proportional in the case of shallow water. (Fig. 17).

著者

Kasahara Keichi

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 (ISSN:00408972)

巻号頁・発行日

vol.35, no.3, pp.473-532, 1957-12-05

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緒論.地震の振動に関する研究の進展について歴史的に考察を行つた.初期の段階においては,最も簡単な条件の震源に基づいて諸研究がなされていたが,その後理論及び観測両面が充実されるにつれて,次第に複雑な条件をもつ震源のモデルが用いられるようになつた.即ち初動分布の規則性が発見された為に,震源に作用する力にも方位性を考える必要が生まれ,叉球状震源に関する理論的研究は,地震動の波形や周期の有する意表を明らかにした.

著者

村井 勇 金子 史朗

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.50, no.3, pp.p329-342,地図4枚, 1976-03

被引用文献数

1

著者

村井 勇 金子 史朗

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.50, no.3, pp.329-342, 1976-03-31