1 0 0 0 OA 神城断層両端部の断層変位地形
- 著者
- 東郷 正美 池田 安隆 今泉 俊文 佐藤 比呂志
- 出版者
- 一般社団法人 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.15, pp.9-16, 1996-11-29 (Released:2012-11-13)
- 参考文献数
- 14
- 被引用文献数
- 1
The Kamishiro fault, extending for at least 20 km from the north Hokujyo basin to the south of Lake Kizaki, is one of major active faults along the Itoigawa-Shizuoka Tectonic Line in central Japan. We investigated detailed features of fault morphology along this fault, by interpretation of large scale aerial photographs. It became clear that faulting characteristics at the both ends of the Kamishiro fault are essentially different. At its northern end, the fault has become inactive progressively southward with time. However, the southernmost portion of the fault is still active in Holocene time, and continues southeastward to the Eastern Boundary fault of Matsumoto basin.At the southernmost portion of the Kamishiro fault, we also found evidence that remarkable thrust-front migration have occurred recently. Young offset features along the main portion of the Kamishiro fault suggest that at least one or two faulting events have occurred in Holocene time, and the latest event occurred probably in historic time.
1 0 0 0 OA 活断層の地中レーダ法によるイメージング:その現状と展望
- 著者
- 笠井 弘幸 阿部 信太郎 鈴木 浩一
- 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.15, pp.73-86, 1996-11-29 (Released:2013-03-22)
- 参考文献数
- 5
Ground penetrating radar uses reflected electromagnetic waves to image the subsurface. Its investigation depth is 2-3m and its resolution is 20-30cm in soil. Because of its very shallow investigation depth, ground penetrating rbdar has been used for finding underground gas pipes, electric cables and buried remains.Ground penetrating ra d ar method has an advantage over the seismic reflection method in tenns of the spread density of sources and sensors. It is necessary in the seismic reflection method to spread sources and sensors in consideration of surface waves because the generation of surface waves makes it very difficult to distinguish reflected waves. However, in ground penetrating radar method, sources and sensors can be spread conveniently with high density for its high resolution because surface waves are not generated in the electromagnetic field.We have devised a new radar system to ap p l y the ground penetrating radar method to geological surveying. In the ordinary radar system, impulsive waves are used as transmission signals, but in the new radar system, sine waves are used with the frequency varied as a step function of the sweeping period of transmission signals. We can obtain the impulsive reception signals such as the ordinary radar system after the convolution integrals between sine-shaped transmission and reception signals. We call the new radar system the Step Continuous Wave Radar(SCWR) systen after the characteristics of its transmission signals. Its investigation depth is 10-15m in soil and 20-30m in rock with resolution of 50-60cm.The SCWR system will provide useful information because it can be carried out speedily and non-destructively on the ground around active faults, before trenching, down to about 10m in depth.In this paper, we will show the imaging of active faults with the SCWR system throu g h the results of the investigation around the Nojima faults which appeared in the Awaji Island with the 1995 Southern hyogo Prefecture Earthquake, and then we will pick up some current problems in the imaging, for example the effective arrangement of sources and sensors for the shorter period of field work and for the three-dimensional imaging with ground penetrating radar, and finally show a conception for the solutions of these problems.
1 0 0 0 OA アメリカ合衆国の活断層データベースとその応用
- 著者
- 奥村 晃史
- 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.2003, no.23, pp.5-12, 2003-06-30 (Released:2012-11-13)
- 参考文献数
- 21
Geologists and seismologists in the United States have been compiling and publicizing databases on possible sources of earthquakes including active faults since early 1970s. The ideas about the database and risk assessment have evolved in close response to public demands raised by such unforeseen earthquake hazards in 1 989 Loma Prieta earthquake and 1994 Northridge earthquake. Though the forecasts of future earthquakes failed repeatedly, the scientific communities always analyzed the failure and improved the knowledge and technology. The faultrupture hazard zone mapping under the Alquist-Priolo act was supplemented by the seismic hazard mapping of liquefaction and landslides. Probabilistic earthquake hazard mapping of Southern California and entire United States clearly demonstrated the advantages of regional ground shaking assessment to the evaluation of fault activity.
1 0 0 0 OA 活断層研究の歴史と課題
- 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.2008, no.28, pp.15-22, 2008-03-31 (Released:2012-11-13)
- 参考文献数
- 95
That faults are the origin of earthquakes was not an accepted theory in Japan for several decades prior to 1960, although the progressive accumulation of fault displacement in the Quaternary Time had been demonstrated in seismic areas. The Earthquake Prediction Program proposed by seismologists in 1962 stimulated geologists and geomorphologists to start active fault studies.During the 1960-1970's, the following results were made clear: 1) the distribution of active faults in onshore Japan, shown in 123 sheet maps of 1: 200,000 scale with detailed inventories by the Research Group for the Active Faults of Japan; 2) the extensive occurrence of strike-slip type active faults, almost none of which was known on the Japanese Islands at that time; 3) the existence of Quaternary crustal stress field with east-west compression in most of the Japanese Islands, recognized from the conjugate fault system of the central Japan; 4) the quantitative relation between earthquake magnitude and length of the surface trace of co-seismic fault for the onland Japanese earthquakes, which has been used in Japan to estimate magnitudes of future earthquakes; 5) the very long recurrence intervals of activity of a fault, generally longer than the order of 1000 years.In 1980-1990's, especially after the 1995-Kobe earthquake, excavation studies were performed extensively in more than one hundred active faults in onshore Japan. The active fault data obtained so far made it possible to prepare seismic hazard maps with probabilities of the occurrence of strong seismic motion in a specified period.
1 0 0 0 OA 陸上活断層の最新活動期の表
- 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.1995, no.13, pp.1-13, 1995-03-25 (Released:2013-03-22)
- 参考文献数
- 74
1 0 0 0 OA 最近10年間の図幅別活断層関連文献集
- 著者
- 松田 時彦 萩谷 まり
- 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.1999, no.18, pp.65-115, 1999-03-31 (Released:2012-11-13)
1 0 0 0 OA 三河湾における深溝断層延長部と中央構造線の音波探査
1 0 0 0 OA 伊予灘北東部海底における中央構造線
1 0 0 0 「要注意断層」の再検討
- 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
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).
1 0 0 0 OA 濃尾地震と関東大震災
- 著者
- 武村 雅之
- 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.2012, no.37, pp.39-44, 2012-09-30 (Released:2016-03-16)
1 0 0 0 糸魚川-静岡構造線活断層系神城断層における地中レーダー探査
- 著者
- 木村 治夫 中西 利典 丸山 正 安藤 亮輔 堀川 晴央
- 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.2013, no.38, pp.1-16, 2013
The Itoigawa-Shizuoka tectonic line (ISTL), which is located between the NE and SW Japan arcs, is one of the most major tectonic lines in Japan. The N-S trending Kamishiro fault located in the northern part of the ISTL active fault system is an east dipping reverse fault. Near the southern part of the fault, the alluvial fan formed by a river flowing toward the southeast is tilted to the west by faulting. To reveal shallow subsurface deformation structure above a depth of 5 m, we carried out ground penetrating radar (GPR) profiling along two survey lines, whose lengths are 50 m and 130 m, respectively, across the fault. The GPR data was collected by common-offset modes using the control unit SIR-3000 (Geophysical Survey System Inc.) and the 200 MHz antenna Model-5106(Geophysical Survey System Inc.), and the station spacing was 0.01 m. The depth converted GPR sections after careful data processing are very concordant with the geological section based on drilling and trenching surveys conducted near the GPR survey. The GPR sections show deformation structure of the fan deposits in detail. The vertical displacement of the top of the fan gravel deformed by the Kamishiro fault is over 3.0 m during the last faulting event.
1 0 0 0 1586年天正地震養老断層震源説を示唆する地形地質学的記録
- 著者
- 須貝 俊彦
- 出版者
- Japanese Society for Active Fault Studies
- 雑誌
- 活断層研究 (ISSN:09181024)
- 巻号頁・発行日
- vol.2011, no.35, pp.15-28, 2011
Fault activity in the Yoro–Kuwana–Yokkaichi fault zone is considered to have been the source of the 1586 Tensho Earthquake. The Geological Survey of Japan conducted array boring and trenching surveys at Hazawa and Niwada within the ~30-km-long Yoro fault system, which is the main component of this major fault zone. This paper reports the main results of these surveys, focusing on the most recent faulting events and with new paleoseismological data.<br>At Hazawa, the boundary between prodelta and delta-front sediments formed within the Kiso River system at around 4 ka has been displaced vertically across the fault by about 15 m, and the top of the deltaic sediments formed at around 1.7 ka by ~10 m, indicating repetitive fault activity since 4 ka. The floodplain on the up-thrown side of the fault has been terraced since about the 8th century; this probably reflects the penultimate faulting event. The last event occurred after the 8<sup>th</sup> century.<br>At Niwada, four offlapping sedimentary units separated by angular unconformities are capped by a buried soil or peat layer containing abundant plant fossils and charcoal fragments that have provided C-14 data to constrain the timing of faulting events. At least three episodes of fault activity have produced cumulative tilting during the period of stable sea level over the last 4 ka. The last two tilting events occurred after the 15<sup>th</sup> century and around the 8<sup>th</sup> century.<br>The most recent faulting events on the Kuwana and Yokkaichi faults occurred after the 13th century. Furthermore, the two most recent rises of relative sea-level probably reflect coseismic subsidence on the Nobi plain about 500 and 1200 years ago. It is highly likely that the Yoro–Kuwana–Yokkaichi fault zone produced both the 1586 Tensho and 745 Tenpyo earthquakes, although geological data alone is insufficient to determine the exact age of these events.
1 0 0 0 OA 糸魚川-静岡構造線活断層系北部神城断層の浅部構造と平均すべり速度
- 著者
- 松多 信尚 池田 安隆 今泉 俊文 佐藤 比呂志
- 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.2001, no.20, pp.59-70, 2001 (Released:2013-03-22)
- 参考文献数
- 12
- 被引用文献数
- 1
The Kamishiro fault is one of the major active faults constituting the Itoigawa-Shizuoka Tectonic Line (ISTL) in central Japan. The Kamishiro fault is an east-dipping reverse fault. This fault cuts and warped the young lake deposits (late Pleistocene and Holocene in age) in the Kamishiro basin. The slip rate on the Kamishiro fault near the surface has been estimated by Geo-Slicer and shallow drillings survey, but was found to be significantly smaller than the vertical slip-rate that was estimated from the displacement of the AT volcanic ash. We carried out a 55 m deep drilling and a seismic reflection profiling using S-waves in this basin to clarify the subsurface structure of the Kamishiro fault. As a result, it was clarified that the Kamishiro fault is associated with drag folding near the surface. If we take the drag folding into account, the overall rate of slip on the fault would be as high as 4.4-5.2mmlyr during the past 28ka.
1 0 0 0 OA 人吉盆地南縁の活断層
- 著者
- 千田 昇
- 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.2000, no.19, pp.87-90, 2000-03-31 (Released:2012-11-13)
- 参考文献数
- 7
The Hitoyoshi Basin is located at the southern part of Kumamoto Prefecture, southwest Japan. The basin has been considered to be a fault angle depression bounded by fault at the southern margin of the basin, named here the southern marginal fault of the Hitoyoshi Basin. This fault extends NE-SW direction for about 22 km, and has a sense of right lateral strike-slip with a northwest downthrown vertical component of displacement.
