{"created":"2021-03-01T06:51:38.671916+00:00","id":32919,"links":{},"metadata":{"_buckets":{"deposit":"601d2e30-feac-4276-9993-7803f913cf59"},"_deposit":{"id":"32919","owner":"1","owners":[],"pid":{"revision_id":0,"type":"depid","value":"32919"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00032919","sets":["80:4535:4787:4793","9:504:4538:4789:4794"]},"author_link":["128370","128369"],"item_4_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"関東地方の地殻下地震の発震機構と震源分布 : とくに活動域について"}]},"item_4_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1984-10-20","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"2","bibliographicPageEnd":"196","bibliographicPageStart":"127","bibliographicVolumeNumber":"59","bibliographic_titles":[{"bibliographic_title":"東京大學地震研究所彙報 = Bulletin of the Earthquake Research Institute, University of Tokyo"}]}]},"item_4_description_13":{"attribute_name":"フォーマット","attribute_value_mlt":[{"subitem_description":"application/pdf","subitem_description_type":"Other"}]},"item_4_description_5":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"Subcrustal earthquakes beneath the Kanto District and vicinity show some intense clusters of hypocenters at some regions and depths, especially in the western part of Ibaraki and Chiba Prefectures. Relative locations and spatial alignments of the hypocenter clusters are derived from the precisely relocated hypocenters by correcting the Pn station biases. For 487 out of 1029 subcrustal earthquakes, which occurred with magnitudes of 4.0 or more in and around the Kanto District during the period from 1963 to 1980, 704 fault-plane solutions, satisfying 10 or more first-motion data have been determined. Variable focal mechanisms of subcrustal earthquakes are caused by the convergence of three lithospheric plates, the intersection of the Northeast Honshu and Izu-Bonin slabs at depths and such additional processes as the back-arc spreading and bending of the lithospheric plate near the trench. Focal mechanisms of earthquakes in the intense clusters have a consistency with the spatial trend in the hypocenter distribution. Two clusters separated by the 140°E line and at different depths beneath the southwestern part of Ibaraki Prefecture show the northwest lineament with the reverse faults of the NW-SE or N-S compression and the western side sinking along the vertical plane. The latter type of earthquake occurrence is also observed for earthquakes beneath the middle part of Chiba Prefecture.","subitem_description_type":"Abstract"},{"subitem_description":"関東地方周辺の地殻下地震は特定の地域・深さで著しい集中の活動を示す.これらの活動域の地震について震源配列,相対位置,発震機構がしらべられた.地殻下地震は東北日木・伊豆小笠原島弧の接合部に集中している傾向がみられ,とくに東北日木側で活発であると共に地震面が北西に彎曲を示す.活動度のもっとも高い茨城県南西部の地殻下地震は深さ・位置の異なる2つの活動域に分けられる.東経140°線の西側の活動域は深さ40～60kmで北西に傾むき下がる配列を示し,東経140°線の東側では深さ60～80kmでむしろ鉛直の配列を示す.1963-1980年,マグニチュード4以上の地震の約半分の地震(1029個のうち487個)について,10個以上の初動データを満足するメカニズム解(704個)を求めることができた.これらの解の内55%が逆断層型でとくに関東地方や東北日本側で卓越し,伊豆諸島では他のタイプのメカニズムもあらわれる.関東地方では南北圧力の逆断層型がみられ,東北日本・伊豆小笠原弧のスラブの接合に伴なう地震面の北西への彎曲に関わるものと思われる.日木海溝の外側では水平の東西張力,海溝内側では鉛直面に沿う西落ちの縦ずれのメカニズムがみられる.東西張力のメカニズムは伊豆・小笠原諸島の西側にもみられ,房総ジャンクション南力では横ずれ型のメカニズムがみられる.これらの複雑な特徴は3つのプレートの収束と東北日本・伊豆小笠原弧のスラブの接合及び背弧拡大などの附加的過程によるものと考えられる.茨城県南西部の2つの活動域の内,西側の活動域の地震は北西-南東(及至南-北)の圧力をもつ逆断層型で,東側の地震は鉛直面に沿う西落ちの縦ずれ型のメカニズムが卓越している.従つて茨城県南西部の2つの地殻下地震の活動域は,①東経140°線の西側=彎曲する東北日本弧のスラブ上面に沿う逆断層地震,②東経140°線の東側=太平洋プレートのスラブ内のやや深い震源で西落ちの鉛直縦ずれ型の地震に分けられる.後者は千葉県中部の深さ60-80kmの活動域にも共通する.","subitem_description_type":"Abstract"}]},"item_4_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"128370","nameIdentifierScheme":"WEKO"}],"names":[{"name":"牧, 正"}]}]},"item_4_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15083/0000032919","subitem_identifier_reg_type":"JaLC"}]},"item_4_publisher_20":{"attribute_name":"出版者","attribute_value_mlt":[{"subitem_publisher":"東京大学地震研究所"}]},"item_4_source_id_10":{"attribute_name":"書誌レコードID","attribute_value_mlt":[{"subitem_source_identifier":"AN00162258","subitem_source_identifier_type":"NCID"}]},"item_4_source_id_8":{"attribute_name":"ISSN","attribute_value_mlt":[{"subitem_source_identifier":"00408972","subitem_source_identifier_type":"ISSN"}]},"item_4_subject_15":{"attribute_name":"日本十進分類法","attribute_value_mlt":[{"subitem_subject":"453","subitem_subject_scheme":"NDC"}]},"item_4_text_21":{"attribute_name":"出版者別名","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute, University of Tokyo"}]},"item_4_text_4":{"attribute_name":"著者所属","attribute_value_mlt":[{"subitem_text_value":"Earthquake Research Institute University of Tokyo"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Maki, Tadashi"}],"nameIdentifiers":[{"nameIdentifier":"128369","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2017-06-26"}],"displaytype":"detail","filename":"ji0592001.pdf","filesize":[{"value":"3.9 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ji0592001.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/32919/files/ji0592001.pdf"},"version_id":"150c3dc7-f4c7-4e42-8aa8-f87f93bce752"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"eng"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"departmental bulletin paper","resourceuri":"http://purl.org/coar/resource_type/c_6501"}]},"item_title":"Focal Mechanisms and  Spatial Distribution of Subcrustal Earthquakes Occurring in Clusters beneath the Kanto District","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Focal Mechanisms and  Spatial Distribution of Subcrustal Earthquakes Occurring in Clusters beneath the Kanto District","subitem_title_language":"en"}]},"item_type_id":"4","owner":"1","path":["4793","4794"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-05-30"},"publish_date":"2008-05-30","publish_status":"0","recid":"32919","relation_version_is_last":true,"title":["Focal Mechanisms and  Spatial Distribution of Subcrustal Earthquakes Occurring in Clusters beneath the Kanto District"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-19T05:38:03.779796+00:00"}