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

松田 時彦

出版者

日本活断層学会

雑誌

活断層研究 (ISSN:09181024)

巻号頁・発行日

vol.1996, no.14, pp.1-8, 1996

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Precaution fault zones designated by Matsuda (1981) are reevaluated using recently-obtained data on the late Quaternary slip-rate and from the result of excavation studies for faults of historical earthquakes. The precaution faults were defined as those with elapse ratio, E=t/R>0.5 (t: elapsed years since the last activity. R: average recurrence interval).<BR>The following three fault z o nes can be excluded from the previously-denoted precaution zones: The Arima-Takatsuki tectonic line (t/R=0.1∼0.4), which have moved in 1596. The Rokko-Awaji fault zone (t/R=0.0∼0.5), of which southern part moved in 1995 and northern part probably in 1586. The Atera fault zone (t/R= 0.3∼0.5 for M8.0 ), which have moved in 1586.<BR>The following fault zones are ascertained to be precaution faults. Segments of the Median Tectonic Line of central Shikoku to central Kii (t/R=0.5∼2.5 for M7.8). The Inadani fault zone (t/R>0.6∼1.6). The central part of Itoigawa-Shizuoka tectonic line (t/R=0.9), which moved about 1200 years ago. The Fujikawa fault zone (t/R>0.9∼1.4). The Kozu. Matsuda-Kannawa fault zone (t/R>1.0∼2.8).

著者

松田 時彦

出版者

公益社団法人 東京地学協会

雑誌

地学雑誌 (ISSN:0022135X)

巻号頁・発行日

vol.102, no.4, pp.354-364, 1993-08-25 (Released:2010-11-18)

参考文献数

45

被引用文献数

3 2

著者

石橋 克彦 太田 陽子 松田 時彦

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.35, no.2, pp.195-212, 1982-06-25 (Released:2010-03-11)

参考文献数

19

被引用文献数

1 1

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Uplifted Holocene marine terraces of Hatsu-shima Island (0.44km2) in the western part of Sagami Bay on the Pacific coast of central Japan have been investigated with special reference to the late Quaternary seismic crustal movement of the island. Hatsu-shima Island, which is located at the top of the western steep scarp of the northernmost part of the Sagami trough, was uplifted almost uniformly by around 2m at the time of the 1923 Kanto earthquake (Ms=8.2).The whole surface of the island consists of a flight of marine terraces developed on Pliocene volcanics. These terraces are clearly classified into three groups; I, II, and III. Terrace I, the highest (about 50m asl), is distributed only in the southeastern small part of the island. Terrace II, 25-40m asl, is the widest in the island and tilting, generally, northwestward. Terraces I and II have been correlated to Obaradai Terrace of about 80, 000yrs B. P. in age and to Misaki Terrace of about 60, 000yrs B. P. in age, respectively, by SUGIHARA (1980) based on marker tephras covering the terraces.Terraces III, rather narrow but well defined especially in the northern and western parts of the island, is distributed along the present shoreline at the foot of a former sea cliff as high as about 20m surrounding Terrace II (or I in the southeastern part). In this paper they are subdivided into three; IIIa, IIIb, and IIIc. Terrace IIIa, the highest and widest among group III, is rather flat with about 10m asl inner margin. Planned excavation at three localities on this terrace has revealed that terrace deposits composed of marine gravel and sand of 1.5-2m thickness rest unconformably on rather weathered bed rock. Fossil shells that were obtained at the base of terrace deposits at Excavation B, which are judged to be in situ and to represent the terrace's age, have been dated at 6, 730±190 14C yrs B. P. (GaK-9080). From this 14C date, as well as from the topographical features, Terrace IIIa can be interpreted as the highest Holocene terrace formed about 6, 000 years ago (so-called Numa Terrace). The height of former shoreline is estimated at around 9m asl. Terraces IIIb and IIIc are narrow emergent shingle beach, whose inner margins are 6-7m asl and about 4m asl, respectively. IIIc includes the emergent beach of 1923 in its lowest part. Although the topographical separation between IIIb and IIIc is not necessarily clear, they can be distinguished from each other as IIIb surface is covered by dense vegetation including many pine trees which have been growing since before the 1923 coseismic uplift, whereas IIIc surface has no vegetation. Therefore, it is almost certain that at least two times of intermittent emergence had occurred between the formation of Terrace IIIa and the 1923 coseismic uplift. However, the dates of emergence have remained undefined, because 14C dates of fossil shells which were collected from Terraces IIIb and IIIc are so much scattered implying that the materials are not in situ. In the northern part of the island there is a prominent flat surface higher than Terrace IIIa, 10-15m asl, where Hatsu-shima village is situated. In this paper it is named IIIa' Surface and considered a secondary surface modified from Terrace IIIa by landslides of a back scarp and artificial alteration based on its sedimentological features, surrounding topographical features, and rather young 14C dates of materials obtained from this surface.

著者

森本 良平 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.39, no.4, pp.935-942, 1962-03-15

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The area around Mt. Gankyoji-yama, 45 km east of Fukui City and 70 km north of Gifu Gity, was attacked by a severe earthquake at 14 h 33 m on August 19, 1961 (The earthquake was later named as Kita Mino Earthquake). In this area, in addition to the damage done to houses and stone walls, fissures were opened on narrow ridges. Many rock fall and earth fall took places on the steep cliffs.

著者

松田 時彦 恒石 幸正

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.48, no.6, pp.1267-1279, 1971-02-27

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A locally destructive earthquake with magnitude 6.6 occurred in Okumino area, Gifu Prefecture, Central Japan on September 9, 1969 (Fig. 1). The damage area is underlain mainly by Paleozoic formations and Cretaceous rhyolitic pyroclastic deposits, which are partly covered with dissected Quaternary volcanoes (Figs. 2 and 3). A number of Quaternary faults which are dominantly of strike-slip nature, occur in Central Japan which includes the epicentral area (Fig. 6). The epicentral area is located about 10km west of a main fault of the Atera fault system, which is an active left-lateral strikeslip fault of Central Japan. Although a few active faults are in the meisoseismal area, no definite evidence of surface faulting was found along any active fault, except some echelon cracks suggesting a left-slip on a fault line at one locality. The push pull distribution of P waves (Fig. 1), the distribution of aftershocks and the shape of the meisoseismal area (Fig. 5) suggest the concealed seismic fault to be a northwest-trending left-lateral strike-slip fault, which strikes parallel to the Atera fault and has the same sense of displacement. The direction of maximum pressure of the present earthquake corresponds well with the Quaternary stress direction, which has been inferred from the study of active fault systems in Central Japan.

著者

太田 陽子 松田 時彦 長沼 和雄

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.29, no.1, pp.55-70, 1976-03-10 (Released:2010-03-11)

参考文献数

21

被引用文献数

1 1

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Seven steps of marine terraces are well developed on the Ogi Peninsula, Sado Island. The seventh (lowest) one is a raised abrasion bench less than 2m high, emerged at the time of the destructive earthquake of 1802, hence it is named the 1802 terrace. The sixth terrace is about 2-4m high, and probably was formed at the time of Holocene transgression. Higher five terraces (Pleistocene terraces V-I) are well preserved over the most part of the peninsula and have the height of 32-40m, 70-55m, 94-118m, 123-137m and more than 165m, respectively.The height of former shorelines represented by shoreline angle of each terrace shows that all the terraces tilt northward. Generally, the higher the terrace, the larger the amount of tilting. However, the tilt of the lowest two terraces (the 1802 and Holocene terraces) is almost the same, ca. 1.5′. This indicates that the 1802 tilting caused by the earthquake was a first event after the formation of the Holocene terrace of ca, 6, 000 years old and the recurrence interval of the events was more than 6, 000 years. A uniform regional difference of 2m in height between these two terraces is probably interpreted as a superposed result of the eustatic lowering of sea level and a regional uplift during last 6, 000 years.It is possible to estimate the average intervals of earthquakes after the terrace formation by comparing the tilting rate of all Pleistocene terraces with that of the 1802's. Thus, the average recurrence intervals are estimated at about 8, 600 years since Terrace III was formed and about 5, 000 years since Terrace IV was formed. These values are consistent with the interval of more than 6, 000 years which is estimated from tilt of the 1802 and the Holocene terraces. It is concluded, therefore, that the earthquake has taken place repeatedly in a similar manner with a recurrence interval of about 5, 000-9, 000 years during at least last 105 years.Uplift and northward tilting of the Ogi Peninsula at the time of the 1802 earthquake (Magnitude 6.6) is significantly larger than those of Awa-shims at the Niigata earthquake of 1964 (M 7.4), though its magnitude was smaller.This fact and the limited areal deformation by the 1802 earthquake imply that the epicenter of this earthquake was located very close to the coast of the Ogi Peninsula, probably within a few kilometers off Shukunegi. A reverse faulting is inferred to have occurred along a northward-dipping fault plane at the 1802 earthquake.

著者

松田 時彦

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.13, pp.85-126, 1974-03

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The Nobi (Mino-Owari) Earthquake (Table 1) of 1891 is the largest earthquakerecordedi inland in Japan, which was associated with surface faulting of strike-slip type. In this. paper the surface fault localities are reexamined based on Koto (1892), Omori (1894) andi other previous papers and recent field studies. The surface faulting appeard on several pre-existing Quaternary fault line (Figs. 1-3).