1998 Hida Mountain earthquake swarm (Part 2)- effect of the swarm on the seismic activity in the surrounding area
| Autor: | WADA, Hiroo, ITO, Kiyoshi, OHMI, Shiro |
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| Jazyk: | japonština |
| Rok vydání: | 2000 |
| Předmět: | |
| Zdroj: | 京都大学防災研究所年報. B. 43(B-1):115-121 |
| ISSN: | 0386-412X |
| Popis: | 1998年8月から始まった飛騨山脈・上高地付近の地震活動は約1年6ヶ月程度継続し, この地域において地震観測が始まってから, 規模(荏5.4)及び期間ともに最大の活動であった。この一連の活動は, 活動初期には飛騨山脈北部全域で活発な活動を示していたが, 1999年にはいってからは, 上高地, 穂高岳付近で活動が短期間に集中して発生する状態に変化したことがわかった。この群発地震活動が周辺域の地震活動域に及ぼした影響について調べた結果, 隣接する長野県中部地域において活動が活発化したことが明らかになった。また, 跡津川断層に沿う活動についても調べたが, 断層西部において活動の低下がみられた。このことは, 群発地震によって応力状態が変化したためと考えられる。 Earthquake swarms in the Hida mountain range started in August, 1998, continued about one and half years and are the largest swarm activities in size (the largest magnitude of 5.4) and in duration time since the micro-earthquake observation started in 1977.More than 9, 200 events have been located by the Kamitakara Observatory during 1.5years. Main activity expanded from south to north along the Hida mountain range in the first month and the activity decreased until February, 1999, after that a new stage of swarm activities began.The influence of the swarms to the seismic activity in the surrounding areas were examined from the frequency of events. The swarm activities did not have an effect on the seismic activity in the southern part of the Hida mountain range, where activities were often changed by the activities in adjacent areas. Seismic activity in the central Nagano Prefecture increased after the Hida Mountain swarm. As for the seismicity along Atotsugawa fault, weak decrease of the activity is seen for three month before the earthquake swarm. |
| Databáze: | OpenAIRE |
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