著者
寒川 旭
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.2011, no.35, pp.67-73, 2011-09-30 (Released:2015-12-09)
参考文献数
20
著者
西村 卓也
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.2017, no.46, pp.33-39, 2017-03-31 (Released:2018-03-29)
参考文献数
26

Many previous studies have revealed distribution of strain rates in the Japanese Islands using data of continuous GNSS station installed since mid 1990’s. They discovered “strain concentration zones” including the Niigata-Kobe Tectonic Zone and the Ou backbone Range in inland and a side of Sea of Japan away from major plate boundaries including the Nankai Trough and Japan Trench. We used GNSS data after the increase of GNSS stations in 2002 and examined distribution of site velocities and strain rates during 2005-2009 with higher spatial resolution. And then, we compared it with major active faults and found that many active faults locate in regions where maximum shear strain rates were high. We also removed elastic deformation due to interplate coupling on the subducting plate interface along the Nankai Trough and compared between distribution of the corrected strain rates and shallow seismicity. The comparison suggests a tendency that the higher maximum shear strain rates, the more frequent shallow M >_ 6 earthquakes occur. We, therefore, suggest that the GNSS data is incorporated into long-term evaluation of large inland earthquakes.
著者
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.1996, no.15, pp.128-132, 1996-11-29 (Released:2012-11-13)
参考文献数
19
被引用文献数
1
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.2010, no.32, pp.87-92, 2010-03-31 (Released:2015-07-31)
参考文献数
23
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.2008, no.28, pp.53-63, 2008-03-31 (Released:2012-11-13)
参考文献数
37

Severe damage from the 1995 Hyogoken-Nanbu earthquake gave us a lesson that a cooperation of research of active fault and strong ground motion is very important for the prediction of strong ground motion from inland shallow earthquake. That is an ace of the scientific world for the mitigation of earthquake damage. In this paper we take up two subjects which are important to put the strong motion prediction to the practical use. One is to estimate the magnitude of a future big earthquake from the active fault data and the other is to estimate the upper level of strong ground motions caused by blind faults. Expectations for active fault research to realize a useful strong motion prediction are described.
著者
渡辺 満久
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.2016, no.44, pp.1-8, 2016-03-31 (Released:2016-10-21)
参考文献数
18

There are several marine terrace surfaces in the southeastern part of Shimokita peninsula, northeast Japan. They are classified into H1, H2, M1, M2 and M3 surfaces in descending order. The M1 and M2 surfaces are correlated with those formed in MIS 5e and in MIS 5a, respectively. The Rokkasho fault merging into the extensive submarine fault along shelf edge in the north has successively deformed these terrace surfaces, resulting in a 1-2 km wide flexural scarp tilting to the east on the M1 and M2 surfaces. Vertical offset of the M1 surface is over 30 m in the north and less than 20 m in the south. The flexural scarp extends at least 15 km to the south of the Takahoko Lake. The Detoseiho fault is a subsidiary branch fault of the Rokkasho fault developed in the Rokkasho flexural scarp. Because the M1 surface is bending toward the east (toward the coast), the sand layer composing of the M2 surface abutted on the monocline slope. Following movements of the Rokkasho fault have deformed the M2 surface in the same direction as the M1 surface, and consequently the M1 and M2 surfaces converged upon in the flexural scarp. This makes it very difficult to distinguish one from the other. Such geomorphic development should be strongly controlled by the activity of active fault differentiating tectonic relief and the width of flexural scarp reflecting the depth of tip of fault plane. Further examinations on active faults extending parallel to the coast lines are required to solve the problems.
著者
萩原 幸男
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.1987, no.4, pp.9-17, 1987-08-20 (Released:2012-11-13)
参考文献数
11
著者
岡村 行信
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.31-39, 2008-03-31 (Released:2012-11-13)
参考文献数
36

Method and result of offshore active fault survey were reviewed. Acoustic and seismic waves are widely used for offshore topographic and geologic surveys. Higher frequency acoustic waves have high-resolution but attenuate rapidly in water or sediments, thus they are mainly used for seafloor topographic survey or shallow high-resolution seismic profiling survey. Multi-narrow beam sounding provided evolutionary detailed seafloor topographic maps that clearly show fault traces. Lower frequency seismic waves are widely used for survey of deep sea and deep subsurface geology, but their resolution is generally too low to evaluate the activity of faults in late Pleistocene or Holocene time. Multi-channel seismic profiling survey and digital signal processing technology tremendously improved quality of seismic profiles. Offshore active fault maps around Japan were published in 1980's and 1990's based mainly on analyses of single channel seismic profiles. The events of active fault have been identified only in shallow bay areas using high-resolution seismic profiles and sediment cores. In contrast, it is generally difficult to determine events in open sea areas, because of low quality of seismic profiles. Multi-channel seismic profiling system using a high-frequency sound source made it possible to obtain high quality seismic profiles in the open shallow sea area and showed an active fault in the source area of the 2007 Noto-Hanto earthquake. In the deep sea, low-frequency seismic profiling system generally show clear geologic structure including active faults, but it is difficult to determine their activity in the late Pleistocene and Holocene period. Analyses of turbidites and dive surveys using submersibles have been conducted to determine the ancient events of fault activity in the deep-sea area. There is no enough data of offshore active faults, especially in very shallow marine area along coast.
著者
岡田 篤正
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.1987, no.4, pp.71-90, 1987-08-20 (Released:2012-11-13)
参考文献数
84
著者
林 豊 前田 憲二
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.2009, no.30, pp.27-36, 2009

Six active fault zones have been selected on the basis of the reports on the long-term evaluation of active faults published until 2008 by the Earthquake Research Committee, Headquarters of Earthquake Research Promotion (ERC/HERP); the paleoseismic activity data of these zones reveal three or more earthquake recurrence intervals. Using the maximum likelihood method, seven probability density functions of a renewal process model are compared in order to determine the function that best fit the paleoseismic activity data of these active fault zones.<br>The exponential distribution model obtained by using the maximum likelihood method does not clearly reveal the earthquakes recurrence intervals. In contrast, the results obtained by using six other statistical models, i.e., Brownian passage time (BPT) distribution, lognormal distribution, gamma distribution, Weibull distribution, double-exponential distribution, and normal distribution, reveal the earthquake recurrence intervals. Thus, the new paleoseismic activity data of major active zones in Japan confirm the provisional conclusion of ERC/HERP, i.e., the exponential distribution does not clearly show the earthquake recurrence intervals. On the other hand, differences among the goodness of fit of the six models excluding the exponential distribution are small.<br>In 2001, ERC/HERP stated that when renewal process model with the BPT distribution is applied to the data of the occurrence intervals of earthquakes in the inland active fault zones in Japan, the aperiodicity parameter of the distribution should be set to 0.24 as a value common to all active faults. The aperiodicity parameter obtained by applying the same method to the data of the six active fault zones is equal to 0.44. Although the aperiodicity parameters, obtained by using the maximum likelihood method, reported in the ERC/HERP's report range between 0.17 and 0.29, those obtained in this study range between 0.09 and 0.66. Thus it is inappropriate to assume the same aperiodicity parameter for all the inland active fault zones in Japan.
著者
鈴木 康弘 岡田 篤正 竹村 恵二 慶 在福 金 幸隆 廣内 大助 伊藤 愛 大石 超 中村 洋介 成瀬 敏郎 北川 浩之 渡辺 満久
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.2005, no.25, pp.147-152, 2005

The Ulsan fault extends for 50 km along the NNW-SSE direction in the southeastern part of the Korean Peninsula; this is one of the most important active faults in Korea. Its paleoseismicity has recently attracted considerable attention. With the support of KOSEF (Korean Science and Engineering Foundation), excavation studies of this fault were conducted in 1999 as a part of the Korea-Japan cooperative research at Kalgok-ri in Kyongju city. The results obtained are summarized as follows. (1) The Ulsan fault plane has an eastward dip of approximately 30 degrees and exhibits typical reverse faulting. (2) It was reactivated three times in the past 30,000 years, in particular, twice after the age of AT tephra (approximately 25,000 years BP). (3) A vertical displacement of approximately 0.8 m occurred during the fault event, and the amount of net slip along the fault plane is calculated to be 1.6 m.
著者
浅田 敏
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.1991, no.9, pp.1-3, 1991-10-31 (Released:2012-11-13)
著者
山口 和雄 加野 直巳 横倉 隆伸 木口 努 田中 明子 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.1998, no.17, pp.54-64, 1998-12-29 (Released:2012-11-13)
参考文献数
32

A seismic survey was conducted across the Tachikawa active fault in the western suburbs of Tokyo metropolitan area. The deep structure and movement of the fault are discussed based on the CMP stacked seismic section together with the geological data published previously. The results are as follows:(1) A flexure, about 150 meters in width, underlies the flexure scarp of the fault and continues vertically down to 1000 meters in depth.(2) The displacement of the fa u lt is about 100 meters upthrow of the northeast side between 300meters and 600 meters in depth, while the displacement at basement depth is about 100 meters downthrow of the northeast side.(3) The northeast side o f the fault had subsided relatively to the southwest side in the past. The fault movement was stopped for a while. Then the fault movement was reversed and the northeast side has been upheaved up to now. This is an inversion tectonics of the fault movement.
著者
東郷 正美 佐藤 比呂志 池田 安隆 松多 信尚 増淵 和夫 高野 繁昭
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.1-8, 1996-11-29 (Released:2012-11-13)
参考文献数
16

By excavation of the Ochikawa-Ichinomiya remain located on the flood plain along Tama River near the boundary between Tama City and Hino City, Tokyo metropolitan area, a fault was found in young alluvium. This fault is regarded as the continuation of Tachikawa fault, a major active fault existing in the left bank area of Tama River, because it is located on the southeastern extension of Tachikawa fault line, and its strike is almost parallel to the Tachikawa fault.Detailed investigation of the fault outcrop made it clear that the last faulting event on the Tachikawa fault had occurred after A. D.1020-1158, the mid-Heian period. At this place, the last faulting event was dominantly strike slip with horizontal shortening of about 0.6 m.
著者
吉岡 敏和 水野 清秀 榊原 信夫
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.1997, no.16, pp.87-94, 1997-08-30 (Released:2012-11-13)
参考文献数
9

The Senzan fault is an active reverse fault directing N-S to NNE-SSW in the central Awaji Island. During the 1995 Hyogoken-nanbu earthquake, a characteristic surface break appeared along the Nojima fault located at the western side of the Awaji Island, however, no surface break had occurred along the Senzan fault. We excavated an exploratory trench on the Senzan fault to detect the age of the faulting events, and we confirmed a reverse fault making a contact between slope deposits and a granitic rock. The youngest age of the hurried soil deformed by the fault is 1161±67 AD. This means that the last faulting event of the Senzan fault occurred after the 12th Century. This event may correspond to the historical Keicho Fushimi earthquake in 1596 AD.