{"created":"2021-03-01T06:51:42.322182+00:00","id":32974,"links":{},"metadata":{"_buckets":{"deposit":"4f576905-79d6-4f85-a75b-a9f1f9824ea7"},"_deposit":{"id":"32974","owner":"1","owners":[],"pid":{"revision_id":0,"type":"depid","value":"32974"},"status":"published"},"_oai":{"id":"oai:repository.dl.itc.u-tokyo.ac.jp:00032974","sets":["80:4535:4807:4808","9:504:4538:4809:4810"]},"author_link":["128566","128567","128568","128563","128564","128565"],"item_4_alternative_title_1":{"attribute_name":"その他のタイトル","attribute_value_mlt":[{"subitem_alternative_title":"栃木県北西部,足尾周辺の群発地震活動地域での微小地震反射波による地殻内不連続面の検出とその特異性について"}]},"item_4_biblio_info_7":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1986-03-31","bibliographicIssueDateType":"Issued"},"bibliographicIssueNumber":"4","bibliographicPageEnd":"686","bibliographicPageStart":"653","bibliographicVolumeNumber":"57","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":"Microearthquake seismograms recorded by the stations in the earthquake swarm area near Ashio on the westren border of Tochigi Prefecture, Central Japan, frequently have two sharp phases following the direct S-wave. They were identified as near vertical S to P-wave (SxP) and S to S-wave (SxS) reflections from an unusual deep crustal discontinuity. Reflection points calculated on the basis of hypocentral coordinates in combination with the traval time data of the reflections were mapped with contour lines of a lkm interval. The discontinuity was estimated to have a depth of about 14 km beneath Ashio dipping southeastward with considerable local irregularities. The ratio of observed amplitudes of SxP to SxS varies from 0.045 to 0.34 for the incident angle of less than 23°. The theoretical amplitude ratio of the reflections agrees well with the observational results when the S-wave velocity decreases from 3.35 km/sec to 0.00 km/sec across the discontinuity. A horizontal extension of the unusual discontinuity strikes in a NE-SW direction along the general trend of the volcanic front in the area. It is suggested from the analysis that the discontinuity is underlain by a material of very low rigidity and the existence of an extensive magma body may be a plausible explanation of the reflections.","subitem_description_type":"Abstract"},{"subitem_description":"北関東,栃木県北西部の足尾地域では浅発性の群発地震活動がみられる.この地域の微小地震の分布および地殻構造を調べるために高感度短周期地震計による4点のテレメータ方式の観測網を設置した.その観測データの解析結果を要約すると以下のようである.i)足尾地域の鄙発地震活動にともなう微小地震の空間分布は震央の集中する数ケ所の部分からなる微細構造をもつ.とくに注目すべきことは足尾山地にみられる活断層(内ノ籠断層)にそう顕著な微小地震活動が存在することである.この断層にそう微小地震についてP波初動の重ね合せによるメカニズム解を求めると走向N28°E,節面の傾斜角が約35°の逆断層の存在が推定される.震源の深さは8.5kmよりも浅い.","subitem_description_type":"Abstract"}]},"item_4_full_name_3":{"attribute_name":"著者別名","attribute_value_mlt":[{"nameIdentifiers":[{"nameIdentifier":"128566","nameIdentifierScheme":"WEKO"}],"names":[{"name":"溝上, 恵"}]},{"nameIdentifiers":[{"nameIdentifier":"128567","nameIdentifierScheme":"WEKO"}],"names":[{"name":"中村, 功"}]},{"nameIdentifiers":[{"nameIdentifier":"128568","nameIdentifierScheme":"WEKO"}],"names":[{"name":"横田, 崇"}]}]},"item_4_identifier_registration":{"attribute_name":"ID登録","attribute_value_mlt":[{"subitem_identifier_reg_text":"10.15083/0000032974","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":"地震研究所"},{"subitem_text_value":"気象庁気象研究所"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Mizoue, Megumi"}],"nameIdentifiers":[{"nameIdentifier":"128563","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Nakamura, Isao"}],"nameIdentifiers":[{"nameIdentifier":"128564","nameIdentifierScheme":"WEKO"}]},{"creatorNames":[{"creatorName":"Yokota, Takashi"}],"nameIdentifiers":[{"nameIdentifier":"128565","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":"ji0574003.pdf","filesize":[{"value":"1.9 MB"}],"format":"application/pdf","licensetype":"license_note","mimetype":"application/pdf","url":{"label":"ji0574003.pdf","url":"https://repository.dl.itc.u-tokyo.ac.jp/record/32974/files/ji0574003.pdf"},"version_id":"56c30953-74b5-44a4-bc1c-4a8671727f12"}]},"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":"Mapping of an Unusual Crustal Discontinuity by Microearthquake Reflections in the Earthquake Swarm Area near Ashio, Northwestern Part of Tochigi Prefecture, Central Japan","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Mapping of an Unusual Crustal Discontinuity by Microearthquake Reflections in the Earthquake Swarm Area near Ashio, Northwestern Part of Tochigi Prefecture, Central Japan","subitem_title_language":"en"}]},"item_type_id":"4","owner":"1","path":["4808","4810"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2008-05-30"},"publish_date":"2008-05-30","publish_status":"0","recid":"32974","relation_version_is_last":true,"title":["Mapping of an Unusual Crustal Discontinuity by Microearthquake Reflections in the Earthquake Swarm Area near Ashio, Northwestern Part of Tochigi Prefecture, Central Japan"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2022-12-19T03:55:18.226049+00:00"}