The Micro-Seismicity and Crustal Structure in the Northern Part of Hokkaido, Inferred from Temporal Observation
The Micro-Seismicity and Crustal Structure in the Northern Part of Hokkaido, Inferred from Temporal Observation
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从时间观测推断北海道北部的微震活动和地壳结构
DOI：
10.4294/zisin1948.55.4_337
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发表时间：
2003
期刊：
影响因子：
--
通讯作者：
T. Moriya
中科院分区：
文献类型：
--
作者：
M. Tamura;M. Kasahara;T. Moriya
利用日本气象厅札幌气象台和北海道大学地震火山研究所的11个地震台和7个常规地震台，对1998年6 ~ 11月日本北海道北方地区（北纬44°以北）的微震活动进行了研究。首先利用密集台网确定了这一时期的91个近震震源。这些震源的数量大约是常规网络的三倍。利用81个地震的735条P波到时记录，采用P波走时反演方法，在假定4层模型（假定厚度为2、8、10 km和无限大）和台站改正的情况下，估计了一维P波速度结构。各层的速度分别为：第一层2.83km/s，第二层5.32km/s，第三层6.32km/s，下半空间6.69km/s。根据P波台站改正资料，该地区在南北方向上可分为日本海西部岛屿区、大陆西部和大陆东部三个平行带。每个区域显示
We have studied micro-seismicity in the northern part of Hokkaido(north above 44°N)from June to November in 1998 combining eleven temporal seismic stations with seven and five routine ones operated by Institute of Seismology and Volcanology (ISV) in Hokkaido University and Sapporo Meteorological Observatory, Japan Meteorological Agency (SMO), respectively. Firstly we determined 91 hypocenters of local earthquakes in this period using the dense network. These hypocenters are about three times of the number of those from the routine network alone. One-dimensional P-wave velocity structure assuming four-layer model (assumed thickness of 2,8,10km and infinite) and station corrections were estimated using a P-wave travel time inversion method with 735 P-wave arrival time records of 81 events. The velocity of each layer was determined to be 2.83km/sec for the first layer, 5.32km/sec for the second one, 6.32km/sec for the third one and 6.69km/sec for the bottom half space. From the P-wave station corrections we obtained, this region can be classified into three zones parallel in the north-south direction; the western islands region in the Sea of Japan, the western part of mainland, and the eastern part of mainland. Each zone shows the