著者
田力 正好 水本 匡起 松田 時彦
出版者
The Association of Japanese Geographers
雑誌
日本地理学会発表要旨集
巻号頁・発行日
pp.232, 2013 (Released:2013-09-04)

活断層(縦ずれ)の断層崖は,その成長と共に比高を増大させ,重力的に不安定となる.その結果,断層崖では地すべり・崩壊などのマスムーブメントが発生しやすくなると考えられる.縦ずれ断層が多く,新第三紀以降の固結度の弱い岩石が多く分布する東日本(糸魚川-静岡構造線(糸静線)以東)においては,特に高頻度で発生していることが予想される.本発表では,東日本のいくつかの活断層帯において,断層崖に生じたマスムーブメントの実例を示し,その形態や変形の特徴,断層崖の形態に及ぼすマスムーブメントの影響,活断層のマッピング・変位量の測定等の際に注意すべき点などについて述べる.断層崖沿いに重力的な変形(マスムーブメント)が認められることは珍しくない.断層崖に地すべり等のマスムーブメントが生じている場合,重力的な変形の影響を受けてテクトニックな要因のみの変形の場合に比べて低断層崖の位置がずれたり,変位量が大きくなったりする可能性がある.このため,活断層のマッピングや変位量の測定の際には,重力的な変形の影響の有無を検討することが必要である.特に大規模な地すべりや,地すべり地形が不明瞭な場合には,断層近傍の地形のみに着目すると地すべり地形を見落とす可能性があるため注意が必要である.
著者
松田 時彦 中村 一明
出版者
The Society of Resource Geology
雑誌
鉱山地質 (ISSN:00265209)
巻号頁・発行日
vol.20, no.99, pp.29-42, 1970-03-02 (Released:2009-06-12)
参考文献数
56

A genetical classification of volcanic clastic deposits is proposed in this paper, which is based on the following four principal criteria:1) place of the eruption by which the material was broughtinto the transporting media : W (subaqueous) or A(subaerial), or O(when it was unrelated directly with the eruption).2) kind of media in which the material was transported to the depositional place : W (water) or A(air) or O(absence of media; this is used for some lava flows and dense landslide deposits).3) place of deposition : W(subaqueous) or A(subaerial).4) mechanism of transportation and settling : F(fall) or R(roll) or T(turbulent flow).Any volcanic clastic deposits might be designated as WWW-T, AAW-F and so on, by putting the result according to the four criteria in a descending order. For lava flows(L), the same principle of classification is applicable, e. g., as WOW-L (or WWW-RL, when it is necessary to indicate rolling(R) mechanism of the emplacement in W media). By the use of O in the first term, this classification also applies to normal clastic sediments, e.g. OWW-T for turbidity current deposits.Discriminating features for each kind of water-laid volcanic clastic deposits are described and several examples are presented.The proposed classification concerns mainly with a sedimentary body as a whole, and not with. descriptive features of particles. Parallel usage of the classic descriptive terminology with the proposed one is recommended, as AAW-F tuff, WWW-T tuff breccia, or tuff breccia (WWW-T), etc.,
著者
千田 昇 竹村 恵二 松田 時彦 島崎 邦彦 池田 安隆 岡村 眞 水野 清秀 松山 尚典 首藤 次男
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.2003, no.23, pp.93-108, 2003-06-30 (Released:2013-03-22)
参考文献数
11

The writers describe the location and active mode of a fault (Funai fault) lying concealed under the town area of Oita City, by analyzing lots of the drilling survey, the reflection method and the Geo-slicer investigation.The Funai fault is the eastern part of“Beppu bay south coast fault group”, which com p osed of the Horita-Asamigawaa fault, Beppu bay south coast fault and Funai fault, extended from west to east with extension about 20km.The very position in Oita plain is considered from Kasugaura to the south of Maizuru bridge located at the left bank of Oita river.It was c o nfirmed in the drilling survey, and the amount of vertical displacement of the K-Ah volcanic ash layer in a main fault is 16m at the Funai castle traverse line. According to existing bore hole data, the maximum amount of displacement of the Funai fault is 18m to the west of Funai castle. The average rate of vertical displacement after the K-Ah volcanic ash (6,300 years BP) is 2.2-2.5m/1000 year, and the Funai fault is estimated one of the A class active faults in Kyushu.The latest activity of the Funaifault is thought to be time between before 1,540yBP dated at the lower part of the uppermost mud layer which does not show the displacement and after 2,350yBP dated in the peat layer in upper sand and gravel bed which shows displacement.The problem in the future is the clarification of the fault continuation to the further east, and it is necessary to elucidate accurate distribution and the activity history of the concealed faults lying under whole the Oita plain.
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.44, no.3, pp.1179-1212, 1967-01
被引用文献数
4

1. 地形的にその存在が推定されていた跡津川断層は,少なくとも庄川-神通川の分水嶺から北東へ常願寺川上流までたしかに存在する.長さ60km以上,部分的にゆるくを彎曲するがほぼ直線状で,その平均走向N60°E,断層面の傾斜はほぼ垂直,断層面上の断層条線はほぼ水平である. 2. この断層線に沿って,古生代の飛騨変成岩類から第四紀の河床堆積物までの地層および隆起小起伏面や段丘面などの地形面が変位している.この断層の変位の向きは多少の垂直成分を伴った右ずれである.この断層が示す変位の水平成分は断層の主部で約3km,垂直成分は,概して北側の相対的隆起でその量は1km以下である.すなわち,この断層は右横ずれ活断層である. 3. 第四紀の地層・地形面は古い時代のものほど大きく変位しているが,それ以前に生じた岩石では,時代が古くなっても変位量はそれ以上増加しない.したがって,現在この断層が示す変位量3kmは第三紀後期以後に生じはじめたと考えられる.数万年前に生成した河岸段丘が20m以上変位しているから,最近の数万年間における平均の変位速度は1~数m/1000年位と考えられる. 4. 段丘の変位や谷の喰違い現象は,この断層が最近地質時代に数十m以下を単位とする小刻みのほゞ同方向の変位を繰返してきたことを示している。また,この断層沿いにみられる断層崖などの断層地形は大地震時に生じる地形によく似ている.これらのことから,この断層の約3000mの変位量は地震時の変位の集積と考えられる.安政5年(1857)の飛騨地震はこの断層の最近の活動の1つと思われる. 5. 断層線上での谷の屈曲・転移のむきは概して右であるが,その量はその断層線から谷頭までの距離の大きな谷ほど大きい.このことは,この断層が活発な右ずれ変位を繰返していること,谷の喰違い地形は変位のむき・量を大略反映していること,谷の古さは断層線よりも上流の部分の長さにほゞ対応していること,を示唆している.このような谷の累進的転位現象の有無・程度は,未知の断層の活動性を知る1つの目安になると思われる.The Atotsugawa fault in central Japan lies about 70 km north of the Atera fault which has recently been described by Sugimura and Matsuda (1965). Although both faults are strike-slip faults of Quaternary age in central Japan, their directions of displacement are opposite to each other. The Atera fault is NW-SE in trend and left-lateral in displacement, while the Atotsugawa fault concerned here is NE-SW in trend and right-lateral.
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

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

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
一般社団法人 日本地質学会
雑誌
地質学雑誌 (ISSN:00167630)
巻号頁・発行日
vol.63, no.746, pp.619-635, 1957-11-25 (Released:2008-04-11)
参考文献数
29
被引用文献数
1
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

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
太田 陽子 松田 時彦 平川 一臣
出版者
日本第四紀学会
雑誌
第四紀研究 (ISSN:04182642)
巻号頁・発行日
vol.15, no.3, pp.109-128, 1976-10-30 (Released:2009-08-21)
参考文献数
28
被引用文献数
14 9

The Noto Peninsula, which projects northeastwards from central Japan is the largest peninsula in the area along the Sea of Japan. This peninsula mostly consists of low relief erosion surfaces and marine terraces truncating the Neogene rocks. Many active faults which displace these geomorphic surfaces as well as alluvial fans are observed as shown in Fig. 1. Figures 2 to 12 represent the detailed topographies and profiles near and across the active faults. All the active faults are expressed as clear fault scarps or scarplets, and most of them are reverse faults with upwarping of the terrace surfaces on the upthrown side.Active faults in this peninsula are classified into three types according to their bearing on geomorphic development. Type I is the first order active fault which resulted in the differentiation of mountain blocks as indicated in Fig. 1. Bijosan I, II and Sekidosan Faults belong to this type. Ochi Depression delineated by these faults at both margins is a kind of ramp valley in a restricted sense rather than graben, as shown in Fig. 13. Fault scarplets at younger uplifted fans (L1) indicate the faulting has still continued until recently. Type II is the second order fault, represented by large scale height difference of marine terraces, and caused subdivision of each mountain block. Togigawa and Sakami Faults belong to this type. All the other active faults except those mentioned above belong to type III, which has resulted in local deformation of marine terrace surfaces. Faults of this type are usually less than 2km in length and less than 20m in vertical displacement. It is especially interesting that the seaward portion of terrace surfaces generally upthrust against their inland parts. Therefore, active faults of type III can be easily recognized by such an abnormal inland-facing scarplet on terrace surface.Active faults in this area are listed in Table 3. It is noticed that the rate of faulting is always more than 10cm/1, 000 years in types I and II, while it is usually less than that in type III. The amount of vertical displacement even in type III is, however, thought too large to be caused by a single earthquake, so that repeated faultings must be considered.Direction of principal axis of maximum compressive stress is N40-60°W, which is inferred from the frequency distribution of trend of active reverse faults shown in Fig. 14. Fault mechanism of a destructive earthquake of 1933 shows also a maximum pressure direction of approximately E-W, probably with a reverse faulting. The direction above mentioned is almost the same as that in the inland areas of central Japan. It is noteworthy, however, that there is a clear difference in fault type between the Noto Peninsula and the other areas of central Japan where strike-slip active faults predominate.
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.
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
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

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

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.