著者

加納 靖之

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.69, pp.41-47, 2016

著者

内田 直希 松澤 暢 三浦 哲 平原 聡 長谷川 昭

出版者

SEISMOLOGICAL SOCIETY OF JAPAN

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.59, no.4, pp.287-295, 2007-03-25

参考文献数

26

被引用文献数

5 4

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Spatio-temporal distribution of quasi-static slip on the plate boundary east off Miyagi and Fukushima prefectures, NE Honshu, Japan is estimated by using small repeating earthquake data. The analysis of small repeating earthquakes has advantages of relatively high spatial resolution, especially near the trench, and the availability of long-term data (22 years) compared to GPS data. The results show that the repeating earthquakes are distributed outside the coseismic slip areas (asperities) of large earthquakes, showing that fault creep is dominant outside the asperities. The cumulative slip (slip histories) of small repeating earthquake groups reveal the existence of many non-steady aseismic slip events. Most of the episodic quasi-static slip events are associated with <I>M</I>≥ 6 earthquakes and they are frequently seen in the areas near the Japan trench in particular. Minor afterslip (∼15cm) of the 2005 Miyagi-oki earthquake (<I>M</I>7.2) is also estimated in the area which encompasses the coseismic slip area of the 2005 earthquake.

著者

〓刀 卓 青井 真 中村 洋光 藤原 広行 森川 信之

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.60, no.4, pp.243-252, 2008-03-31

被引用文献数

5

著者

岡野 健之助 木村 昌三

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.49, no.3, pp.361-374, 1996-11-23

参考文献数

45

被引用文献数

5 1

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We propose a new idea for the crustal movements associated with past great Nankai earthquakes in Shikoku and the surrounding region, Southwest Japan. This study makes clear that the movements are not due to the oblique subduction of the Philippine sea plate, but due to superposition of strong seismic shaking to the uppermost crust in a compressional stress state in the E-W direction. The ground of this idea is as follows: at the time of the 1707, 1854 and 1946 Nankai earthquakes the Kochi plain subsided and the Muroto and Ashizuri peninsulas uplifted, whereas old documents show that the Kochi plain did not subside at the time of the 1605 Nankai earthquake and therefore no uplifting of the peninsulas is inferred because it is based on a set of subsidence of the Kochi plain and uplifting of the Muroto peninsula appearing at the time of the 1707, 1854 and 1946 Nankai earthquakes. This is explained by the reason why the 1605 (Keicho) earthquake was not accompanied with strong shaking of the ground owing to the tsunami earthquake. Next, because the uplifted peninsulas have anticline axes of the N-S direction, from unconsistency in stress direction it is difficult to attribute the uplifting to the subduction in the NW direction of the Philippine sea plate. On the other hand, it is easily explained that the uplifting was caused by the stress in the EW direction enhanced by strong seismic shaking. Tosa bay, which spreads between the Muroto and Ashizuri peninsulas, is characterized by depression. To be able to explain this depression is not by the elastic rebound theory, but by our idea. The undulation in the forearc zone composed of anticlines (peninsulas) and wide depressions (bays), which range alternately along the Japan island arc, can not also explained by the elastic rebound theory. In addition, we consider that the compressional strain variation in the NW direction of the ground surface observed at present in Shikoku does not result from the oblique subduction in the NW direction of the Philippine sea plate, but it is recovering the overdisplacement of the ground surface caused by the coseismic movement (2-3m at the ground surface) in the SE direction of the Muroto promontory by reverse faulting of the 1946 earthquake. Moreover, this study shows that unconsistency in directions of P axes between the 1946 Nankai earthquake and mantle earthquakes presently occurring in Shikoku and its vicinity is succesfully explained by taking account of constraint of the displacement in the direction along the Japan island arc.

著者

松村 正三

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.49, no.1, pp.85-88, 1996-05-24

参考文献数

15

被引用文献数

3

著者

河野 俊夫 仁田 交市 松本 聡 堀内 茂木 岡田 知己 開原 貴美 長谷川 昭 堀 修一郎 海野 徳仁 鈴木 将之

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.46, no.2, pp.85-93, 1993-09-24

参考文献数

30

被引用文献数

8

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

功刀 卓

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.53, no.1, pp.89-93, 2000-07-25

参考文献数

13

被引用文献数

2 6

著者

瀬野 徹三

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.46, no.4, pp.461-477, 1994-03-01

参考文献数

63

被引用文献数

2 1

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Tectonics of the Taiwan region is reviewed. Relative plate motions so far obtained are described and rated. The most reliable solution gives 7.4cm/yr Philippine Sea-Eurasian motion in the N50&deg;W direction in central Taiwan. Plate boundary geometries and modes of plate consumption in the region are discussed on the basis of geophysical, geological and geomorphological data. The major thrust zones at the Western Foothills and the Longitudinal Valley constitute mechanical plate boundaries, but a considerable fraction of the relative plate motion is also consumed by the strike-slip faulting off the southeast coast of Taiwan.<br>The cause for the occurrence of the strike-slip faulting off the southeast coast of Taiwan is discussed based on the various models so far proposed. The bending of the Philippine Sea plate due to the subduction at the Ryukyu Trench and the collision in the Longitudinal Valley are similar to the tectonics of the Izu Peninsula region in Japan, and are the most likely cause for the strike-slip faulting.<br>The reconstruction of the motion and plate boundaries in the vicinity of Taiwan for the past 4-6m. y. is reviewed. The Philippine Sea-Eurasian motion for the past 4 Ma is similar to the present one. The motion prior to 4 Ma may be more northward than present due to the absence of subduction at the Philippine Trench. The Luzon arc started to collide with the continental margin of S. E. China around 4 Ma.

著者

弘瀬 冬樹 中島 淳一 長谷川 昭

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.60, no.3, pp.123-138, 2008-02-15

参考文献数

46

被引用文献数

6

著者

加納 靖之

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.70, pp.171-182, 2017-11

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It has long been believed that a M6.1 earthquake occurred on November 14, 1831 in Saga, southwest Japan. The event relies on a single entry from note of “Tenpo Zakki", which is a collection of miscellaneous notes between 1831 and 1844. Here we propose that the location for the earthquake is likely misinterpreted. Reexamination of the note shows that the earthquake occurred on November 13, 1831, as was recognized in 1919. The original location was thought to be in Saga because according to the note the earthquake was reported from “Hizen-no-kami” (lord of Saga). Analyses of the time it took for the news to reach Edo (Tokyo) show that the location of the earthquake is possibly not Saga, but Aizu, in northeast Japan. The note of “Tenpo Zakki” shows that the information of the event reached Edo in 5 days. However, it was impossible to deliver a letter from Saga to Edo in 5 days at that time. No description on the earthquake was found in diaries written around Saga.“Tenpo Zakki”might have mistaken“Higo-no-kami”(lord of Aizu) for “Hizen-no-kami".This result contributes to improvement of the list of historical earthquakes for Japan.

著者

井上 直人 田中 靖之 伊藤 陽之 岩野 祥子 北田 奈緒子 福田 洋一 竹村 恵二

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.57, no.1, pp.45-54, 2004-08-25

著者

谷口 薫 渡辺 満久 鈴木 康弘 澤 祥

出版者

SEISMOLOGICAL SOCIETY OF JAPAN

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.64, no.1, pp.11-21, 2011-08-25

被引用文献数

2

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The 150 km long Itoigawa-Shizuoka Tectonic Line Active Fault System (ISTL) in central Japan is one of the most active fault systems in Japan. Paleoseismologcal studies 1980s have revealed that the most recent event and the average recurence interval of the ISTL. The approximately 7 km long portion of the fault system between Matsumoto and Okaya has been regarded as a gap without any active fault trace. The gap namely the "Shiojiri Pass Gap" has long been taken as a segment boundary owing to the geometric discontinuity. Recent geomorphological analyses of the gap have demonstrated a through-going left-lateral slip assocaited with recent earthquakes in this area, based on aerial photograph interpretation and excavation studies. Excavation study on this portion revealed that the latest faulting event occurred between 1,700 cal. B.P. to 1,310 cal. B.P. (255 A.D. -645 A.D.). The timing of the last faulting event at this study area coincides with the timing in the Gofukuji fault and Okaya fault. The active faults extending from the Matsumoto basin as far as the northwestern margin of the Suwa basin display the evidence for its recent reactivation at the same time.

著者

石橋 克彦

出版者

日本地震学会

雑誌

地震. 2輯 (ISSN:00371114)

巻号頁・発行日

vol.62, no.1, pp.13-17, 2009-08-31