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全文: "直下型地震" "南関東"
73件中 1-20の結果を表示しています
  • 鈴木 毅彦
    地学雑誌
    2007年 116 巻 3-4 号 Plate1-Plate2
    発行日: 2007/08/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 鈴木 毅彦, 中林 一樹, 江口 孝雄, 笠原 順三, 小原 一成, 瀬野 徹三, 下川 浩一
    地学雑誌
    2007年 116 巻 3-4 号 309-312
    発行日: 2007/08/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 中林 一樹, 瀬野 徹三
    地学雑誌
    2007年 116 巻 3-4 号 313-324
    発行日: 2007/08/25
    公開日: 2009/11/12
    ジャーナル フリー
    Earthquakes can be classified into three groups geophysically : (a) Interplate earthquakes, which occur at the boundary between two plates ; (b) intraslab earthquakes, which occur within the subducting plate ; and, (c) intraplate earthquakes, which occur within the overriding plate. Directly beneath earthquakes are defined as earthquakes that occur just beneath people or artificial structures, causing casualties and damage. All three types of earthquake can be directly beneath earthquakes if they occur beneath or close to a land area. Earthquakes occurring beneath the Tokyo Metropolitan Area are those within : (1) the Okhotsk plate (type c); (2) at the interface between the Philippine Sea and Okhotsk plates (type a); (3) within the Philippine Sea slab (type b); (4) at the interface between the Philippine Sea and Pacific slabs (type a); and, (5) within the Pacific slab (type b). Although all of these types of event could be directly beneath earthquakes, damage caused by (1) or (2) seems to be larger than that caused by the others. There does not seem to be a consensus yet on rating the probabilities of the future occurrence of these events. It is important to conduct future studies on what types of earthquake pose a future threat beneath the Tokyo Metropolitan Area.
    An earthquake as a geophysical phenomena is not a disaster. When an earthquake causes various human casualties, it is called a disaster. If a huge scale of damage is caused by an intermediate scale of earthquake, even if the earthquake is not so severe the result might be a largescale disaster. When the next earthquake of M7 class hits central Tokyo, it is imaginable that it will cause a large-scale disaster. It is called the next Tokyo Earthquake which is an earthquake occurring directly beneath the Tokyo Metropolitan Area, in this volume. We have to prepare various measures against the next Tokyo Earthquake, which require us to understand the general nature of the disaster caused, and to estimate the extent of damage. In 2005, the Cabinet Office, Government of Japan conducted damage estimation research on earthquakes occurring below the Tokyo Capital Region. Eighteen types of earthquake were evaluated under various conditions including season, time of occurrence, and wind speed. In 2006, Tokyo Metropolitan Government (TMG) also conducted damage estimation research on the next Tokyo Earthquake to understand the damage that would occur under the jurisdiction of each government- Special ward. of central Tokyo, City, Town, and Village- because each local government has to revise its earthquake disaster management plan.
    According to these damage estimations, the Northern Tokyo Bay Earthquake of M7.3 causes most damage under conditions of : occurring on a weekday evening in winter with strong winds of 15m/s. In the case of Cabinet Office, Government of Japan research, 850, 000 houses collapse or are destroyed by fire, and there are 11, 000 fatalities. This scale of damage to housing is eight times that of the Hanshin-awaji Earthquake in 1995. As a result, this must be called a super urban disaster, compared to the Hanshin-awaji Earthquake, which was an urban disaster. Cabinet Office, Government of Japan published “General Policy Principles Relating to Countermeasures Policies for Tokyo Earthquakes” in 2005 and the “Tokyo Earthquake Disaster Mitigation Strategy” in 2006. TMG revised the “Earthquake Disaster Management Local Plan” in 2007. TMG plans to reduce damage by half over the next decade.
  • 伊川 美保, 楠見 孝
    日本リスク研究学会誌
    2018年 28 巻 1 号 23-30
    発行日: 2018/09/25
    公開日: 2018/10/19
    ジャーナル 認証あり

    Numeracy is defined as the ability to understand and use mathematical and probabilistic concepts, and one of the central components of risk literacy. However, there were not so many studies about the effect of numeracy on fear after risk information was provided. This study conducted a nationwide online survey to investigate the effect of numeracy on fear when providing information about risk comparison: a method to compare same risks at different times. The reason why risk comparison was used is that it is one of the methods for communicating risk as probabilistic concept. Results showed that people with higher numeracy more decreased their fear after the level of risk decreased, while people with lower numeracy increased their fear. These results were obtained with two materials about radioactive substances in food and Tokyo inland earthquake.

  • 荻野 治
    低温工学
    1995年 30 巻 3 号 113
    発行日: 1995/03/25
    公開日: 2010/02/26
    ジャーナル フリー
  • 瀬野 徹三
    地学雑誌
    2007年 116 巻 3-4 号 370-379
    発行日: 2007/08/25
    公開日: 2009/11/12
    ジャーナル フリー
    I discuss the danger of earthquakes occurring directly beneath the metropolitan area from temporal and geographical viewpoints. Temporally, large (M>7) earthquakes in Kanto occur 70 years before and a few years after great interplate Kanto earthquakes. The recurrence times of such great earthquakes are more than 220 years. Because 80 years have passed since the last one, at least60 years remain before reaching the active period. It is not legitimate to calculate the probability of large earthquakes occurring in the near future, using the rate of occurrence during the active period before a great earthquake. From a geographical viewpoint, S. Kanto is located in the outer zone south of the Median Tectonic Line, where few active faults are distributed. However, in S. Kanto, exceptionally, the Tachikawa fault and the 1855 Ansei-Edo earthquake are located in the outer zone. This zone is specified by a low-velocity zone in the mantle wedge of the upper plate. Dehydration from the subducting slab may weaken the upper plate in this zone, producing anomalous intraplate earthquakes. The upper crust above this low-velocity area should be marked especially as an area having a potential for large earthquakes in the future. The probability of M7 earthquakes being generated at the interface between the Philippine Sea and the upper plates is small. Temporally, the danger of large earthquakes occurring in the near future beneath the metropolitan area does not seem to be large.
  • 加藤 孝明
    生産研究
    2012年 64 巻 4 号 429-432
    発行日: 2012/07/01
    公開日: 2013/02/23
    ジャーナル フリー
    2012年1月大手新聞社は科学的知見をもとに「マグニチュード (M) 7級の首都直下地震が今後4年以内に約70%の確率で発生する」と報道した. その後追随したマスコミは, 「東京湾北部地震」を「首都直下地震」として取り扱って報道した. 明らかな誤解である.
    ここでいう「首都直下地震」は, 首都圏のどこかで起こる直下型地震のことをいう. 一般に直下地震の強震範囲は限定され, 首都圏全体が強震するわけではない. したがって, ある場所から十分に遠くで地震が起こっても被害は生じない. 4年で70%の発生確率の地震は, そういう地震をすべて含んだものである. 「東京湾北部地震」の発生確率ではないし, ある特定の場所が強震する確率ではない.
    今回の一連の報道は, 一見, 社会全体として防災意識を高め, 防災対策の推進に寄与したと言えそうだが, その一方で, 負の側面がある. 科学的な知識が正しく社会に伝わっていない. 対策推進に寄与したことは免責にならない. 科学的に正しい知識をもって防災意識を啓発し, 同時に防災対策を推進できる状況をつくることが本来の状況である.
    本稿では, 1月23日報道の情報ソースのいう確率とその後の報道の確率の違いが異なることを解説した上で, 「M7級首都直下地震の発生確率」と「首都圏内のある特定の場所 (或いは, 地域) がM7級首都直下地震によって強震する確率」との関係を示し, 地震の発生確率の適切な提示の仕方について論考する.[本要旨はPDFには含まれない]
  • 辺見 弘
    日本内科学会雑誌
    2008年 97 巻 10 号 2517-2522
    発行日: 2008年
    公開日: 2012/08/02
    ジャーナル フリー
  • 多田 尭
    地学雑誌
    1987年 96 巻 4 号 201-208
    発行日: 1987/08/25
    公開日: 2009/11/12
    ジャーナル フリー
    Studies of the crust and upper mantle structure in and around the Kanto Plain was reviewed. It has been revealed that the crust under the Kanto Plain has no distinct granitic layer and that the crust and the upper mantle under the southern half of the Kanto Plain is the Philippine Sea Plate which is subducting under the North American Plate. It is supposed that the anomalous crustal structure, i.e., lack of the granitic layer, is a cause of low activity of shallow earthquake under the Kanto Plain. The tearing of the Philippine Sea Plate under the Tokyo Bay is considered to be the cause of the occurrence of destructive earthquakes in the metropolitan Tokyo.
  • 廣田 篤彦, 高山 元, 坪井 善道
    日本建築学会技術報告集
    1996年 2 巻 3 号 230-235
    発行日: 1996/12/20
    公開日: 2017/01/25
    ジャーナル フリー
    This paper examines and analyzes perception of earthquake within people living in the Tokyo area. The findings indicate that as many as 60% of the respondents think that a big earthquake will occur in the metropolitan area within next ten years and over 70% feel uneasy. After the Hanshin Earthquake, those who have hastened to protect their homes with new counter disaster measures have increased. The proves that more and more people are becoming increasingly aware of the importance of counter disaster provisions.
  • 川崎 一朗, 松田 恵子
    地震 第2輯
    1987年 40 巻 1 号 7-18
    発行日: 1987/03/25
    公開日: 2010/03/11
    ジャーナル フリー
    There are six subcrustal earthquake nests (seismically active regions) of sizes of about 20km in the south Kanto district, central Japan. Magnitudes of interplate seismic couplings between the Eurasia, the Pacific and the Philippine Sea plates descending below the south Kanto district have been estimated at these nests.
    There was one event (called a master event) of magnitude of about 6.0 or smaller at each earthquake nest, for which the previously published estimate of the scalar seismic moment by the waveform analysis or moment tensor inversion was used. Scalar seismic moments of smaller events have been inferred by Rayleigh wave amplitude relative to those of corresponding master event on vertical component records of five WWSSN stations within about 30° epicentral distance. The interplate seismic coupling at each nest has been obtained as a ratio of accumulated seismic moment to that predicted by relative plate motion models. Thus determined magnitudes of the interplate seismic coupling are 0.1-0.2, comparable to those at continental slope area between the Japan Islands and the Japan trench.
    Above estimate suggests a potential ability of brittle fracturing along the interplate boundary between the Philippine Sea and the Eurasia plates at 30-50km depths directly below the Metropolitan Tokyo, in the middle of the south Kanto district. This raises a new possibility on a hypocenter location of the recurrent Tokyo earthquakes, which periodically destroyed the Metropolitan Tokyo once about one hundred years in historic times.
  • 中川 雅之
    都市住宅学
    2005年 2005 巻 50 号 3-8
    発行日: 2005/07/31
    公開日: 2012/08/01
    ジャーナル フリー
  • 黒澤 伸
    日本臨床麻酔学会誌
    2013年 33 巻 4 号 513-515
    発行日: 2013年
    公開日: 2013/09/13
    ジャーナル フリー
  • 岡田 義光
    地学雑誌
    2007年 116 巻 3-4 号 307-308
    発行日: 2007/08/25
    公開日: 2009/11/12
    ジャーナル フリー
  • 市川 政治
    Papers in Meteorology and Geophysics
    1987年 38 巻 3 号 203-236
    発行日: 1987年
    公開日: 2007/03/09
    ジャーナル フリー
     日本の内陸に発生した極浅発地震の各種前兆現象について、前兆現象先行時間の常用対数と地震の規模との関係を回帰分析した結果、両者に統計的に有意な相関を示すものが少なく、前兆現象検出に問題がありそうなことがわかった。
     そこで、Fuzzy集合論に基づき、地震空白域や地震活動静穏化現象、若干の地球物理及び化学的前兆観測記録中の異常自動検出プログラムを開発した。このプログラムで検出した異常から地震の予知率や適中率を調べたが、これらは、たかだか10%程度、良くても50%程度であること、又、地震活動パターンの異常による予知率や適中率には顕著な地域性のあることがわかった。
     さらに、開発した各種プログラムを総合して、地震活動パターンの異常解析システムの開発を試みた。
  • 正田 浩司
    地学教育と科学運動
    2008年 58.59 巻 7-16
    発行日: 2008/07/24
    公開日: 2018/03/29
    ジャーナル フリー
  • 廣井 脩, 中森 広道
    地学雑誌
    1993年 102 巻 4 号 482-488
    発行日: 1993/08/25
    公開日: 2010/11/18
    ジャーナル フリー
  • 新地理
    1996年 44 巻 2 号 37-40
    発行日: 1996/09/25
    公開日: 2010/04/30
    ジャーナル フリー
  • 竹本 浩, 川崎 一朗
    地震 第2輯
    1983年 36 巻 4 号 531-539
    発行日: 1983/12/25
    公開日: 2010/03/11
    ジャーナル フリー
    Kinugawa area (N36.0°-36.3°, E139.7°-140.0°), the southwestern part of the Ibaraki prefecture, is one of earthquake clustering regions at depths from 40km to 60km in the Kanto district, central Japan. A seismic moment of an earthquake of August 4, 1974, which is the largest event (M5.8) in the past two decades in the Kinugawa area, is obtained by the least square's method for P wave amplitude data from WWSSN long period records. The seismic moment obtained is 0.77×1025dyne·cm with a focal mechanism of low-angle thrusting to the NNW direction.
    There were 2 events of a magnitude larger than 5.4, excluding the largest event, in a period of 15 years from 1966 to 1980. The seismic moments of the events are estimated by the Rayleigh wave amplitudes from the WWSSN long period records of SHK relative to that of the largest event. Thus, the total amount of the seismic moment released in the Kinugawa area (120km2) during the 15 year period is 0.98×1025dyne·cm. This estimation is about 20-30% of an amount that is predicted by a simple scheme on the basis of relative movements of the Philippine Sea and Eurasian plates in the Kinugawa area.
  • 齊藤 泰, 清宮 理, 日下部 治, 下迫 健一郎, 川上 泰司
    構造工学論文集 A
    2010年 56A 巻 393-406
    発行日: 2010年
    公開日: 2010/08/01
    ジャーナル フリー
    The Tokyo Port Seaside Road Bridge is under construction to cross Tokyo navigation channel. Its main bridge is a 3-span steel truss bridge with a center span of 440m. Soil condition of construction site is very soft clay and the steel pipe sheet pile foundation is adopted. To evaluate seismicity of the bridge at vigorous seismic activity area, dynamic response analysis is carried out. The super structure and sub structure is simultaneously modelled to consider interaction of them. Large sectional force and deformation are calculated at truss sections, therefore an isolation bearing consisting of sliding system and rubber buffer is installed between the truss part and the reinforced concrete pier.
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