Post 2000-swarm microearthquake activity in the principal focal zone of West Bohemia/Vogtland: Space-time distribution and waveform similarity analysis
Post 2000-swarm microearthquake activity in the principal focal zone of West Bohemia/Vogtland: Space-time distribution and waveform similarity analysis
复制标题
西波希米亚/沃格特兰主震区2000年后群微地震活动：时空分布与波形相似性分析
DOI：
--
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
J. Michałek
中科院分区：
文献类型：
--
作者：
T. Fischer;J. Michałek
我们给出了2001年至2007年11月科斯特尔震源区的地震活动模式，该震源区是最近西波希米亚/沃格特兰震群地区最活跃的地区。虽然2001年的特点是以少数微震群的形式消灭了2000年的震群活动，但在2002年至2003年期间几乎没有发生地震活动。自2004年以来，地震活动以反复发生的微震群的形式出现。我们使用了一种相对定位方法，将震群后活动的震中位置与2000-震群的几何形状联系起来。我们发现，活性集中在几个团簇中，这些团簇被反复激活。一些星系团与前一次活动的位置重合；另一些星系团激活了诺维科斯特尔断层南缘迄今不活动的深部段。除了震中向原活动区边缘移动外，我们还观察到活动向南迁移，地震最大深度从10公里增加到13公里。波形相似性分析表明，有些断裂片只由一个重复激活的断裂面组成，而另一些断裂片则由几乎同时激活的多个不同方向的断裂面组成。大多数震源机制与震源几何形状一致，表现为NNW-SSE走向的陡峭断层面，具有左旋走滑机制和不同的倾滑分量。
We present the pattern of seismic activity in the period between 2001 and 2007 for the Nový Kostel focal zone, which is recently the most active zone of the West-Bohemia/Vogtland earthquake swarm region. While the year 2001 was characterized by dying out of the 2000-swarm activity in the form of a few microswarms, almost no seismicity occurred in the period between 2002 and 2003. Since 2004 an elevated seismic activity occurs in the form of repeating microearthquake swarms. We used a relative location method to relate the hypocenter positions of the post-swarm activity to the geometry of the 2000-swarm cluster. We found that the activity has concentrated in several clusters, which have been repeatedly activated. Some clusters coincide with the position of the previous activity; the others have activated so far inactive deep segments at the southern edge of the Nový Kostel fault. Besides the shift of the hypocenters to the edges of the previously active area we observe a southward migration of the activity and an increase of maximum depths of earthquakes from 10 to 13 km. The waveform similarity analysis disclosed that some fault patches consist of only a single, repeatedly activated fault plane, while the others consist of multiple, differently oriented fault planes activated almost simultaneously. Most of the focal mechanisms are consistent with the geometry of hypocenters showing NNW-SSE trending steep fault planes with left-lateral strike-slip mechanisms and varying dip-slip component.