Aftershock seismicity and fault structure of the 2005 West Off Fukuoka Prefecture Earthquake (MJMA7.0) derived from urgent joint observations
Aftershock seismicity and fault structure of the 2005 West Off Fukuoka Prefecture Earthquake (MJMA7.0) derived from urgent joint observations
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根据紧急联合观测得出的 2005 年福冈县西岸地震（MJMA7.0）的余震地震活动性和断层结构
DOI：
10.1186/bf03352668
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
M. Hori
中科院分区：
文献类型：
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作者：
H. Shimizu;H. Takahashi;T. Okada;T. Kanazawa;Y. Iio;H. Miyamachi;T. Matsushima;M. Ichiyanagi;N. Uchida;T. Iwasaki;H. Katao;K. Goto;S. Matsumoto;N. Hirata;S. Nakao;K. Uehira;M. Shinohara;H. Yakiwara;N. Kame;T. Urabe;N. Matsuwo;Tomoaki Yamada;A. Watanabe;K. Nakahigashi;B. Enescu;K. Uchida;S. Hashimoto;S. Hirano;T. Yagi;Y. Kohno;T. Ueno;Masaki Saito;M. Hori
2005年3月20日，日本九州北部福冈县西部近海发生MJMA7.0级大地震。日本多所大学的团队进行了一系列联合观测，旨在调查余震活动。主震发生后，余震区周边陆地立即安装了6个在线遥测地震台和17个离线记录地震台。由于余震主要发生在近海地区，我们还在余震区及其附近上方安装了11台海底地震仪（OBS），以获得准确的震源位置。 OBS观测于2005年3月27日至4月13日进行。我们进一步进行了临时GPS观测，在余震地区周围部署了10个GPS接收机。余震主要沿约25公里长的西北-东南走向排列，主余震区的震源分布在近垂直的平面上，深度为2~16公里。主震位于主余震区中部附近，深度约10公里。 MJMA5.8最大余震发生在主余震区东南边缘附近，随后余震区向二次余震活动定义的SE方向扩展约5公里。余震活动高峰后，余震区域并未出现扩大，余震活动逐渐减弱。余震定义的震源和发震应力的分布表明，2005年福冈县西近海地震发生在警固断层的西北延伸断层上，该断层沿西北-东南方向延伸穿过福冈都市圈，最大的余震发生在警固断层的西北端。
On March 20, 2005, a large MJMA7.0 earthquake occurred in the offshore area, west of Fukuoka prefecture, northern Kyushu, Japan. A series of joint observations were carried out by teams from several universities in Japan with the aim of investigating the aftershock activity. Six online telemetered and 17 offline recording seismic stations were installed on land around the aftershock area immediately followed the occurrence of the mainshock. Because aftershocks were located mainly in offshore regions, we also installed 11 ocean bottom seismometers (OBSs) just above the aftershock region and its vicinity in order to obtain accurate locations of hypocenters. The OBS observation was carried out from March 27 to April 13, 2005. We further conducted temporary GPS observations in which ten GPS receivers were deployed around the aftershock region. The aftershocks were mainly aligned along an approximately 25-km-long NW-SE trend, and the hypocenters of the main aftershock region were distributed on a nearly vertical plane at depths of 2–16 km. The mainshock was located near the central part of the main aftershock region at a depth of approximately 10 km. The largest aftershock of MJMA5.8 occurred near the southeastern edge of the main aftershock region, and the aftershock region subsequently extended about 5 km in the SE direction as defined by secondary aftershock activity. Enlargement of the aftershock region did not occur after the peak in aftershock activity, and the aftershock activity gradually declined. The distribution of hypocenters and seismogenic stress as defined by aftershocks suggest that the 2005 West Off Fukuoka Prefecture Earthquake occurred on the fault that is the NW extension of the Kego fault, which extends NW-SE through the Fukuoka metropolitan area, and that the largest aftershock occurred at the northwestern tip of the Kego fault.