Regional centroid moment tensor inversion of small to moderate earthquakes in the Alps using the dense AlpArray seismic network: challenges and seismotectonic insights
Regional centroid moment tensor inversion of small to moderate earthquakes in the Alps using the dense AlpArray seismic network: challenges and seismotectonic insights
复制标题
使用密集 AlpArray 地震网络对阿尔卑斯山小到中度地震进行区域质心矩张量反演：挑战和地震构造见解
作者：
G. Petersen;S. Cesca;S. Heimann;P. Niemz;T. Dahm;D. Kühn;J. Kummerow;T. Plenefisch
抽象的。中欧阿尔卑斯山脉的特点是地壳不均匀，在沉积前陆盆地附近聚集了不同的构造单元和地块。质心矩张量反演提供了对地震和相关构造过程的断层机制的洞察，但在这样的环境下明显加剧了这种情况。
由于密集的AlpArray地震台网和我们灵活的基于自举的反演工具Grond，我们能够针对所获得的矩张量和质心位置的不确定性测试不同的设置。我们评估了频带、方位差、输入数据类型和距离范围的影响，并研究了非双耦合(DC)分量的出现和可靠性。我们推断，对于大多数地震(Mw≥3.3)，在0.0 2~0.0 7 HZ的频带内采用时域全波形和频域幅值谱的组合是合适的。根据我们方法论测试的结果，我们使用MW>；3.0对事件进行偏矩张量(MT)和反演。在这里，我们提出了2016年1月至2019年12月期间的75个地震解决方案，并在历史地震的地震构造背景、过去30年的地震活动和GNSS形变数据中分析了我们的结果。我们研究了过去几十年地震活动相对较高的地区，即西部阿尔卑斯山、加尔达湖周围地区和南阿尔卑斯山东部，以及距离研究区域更远的星系团，即迪纳里德山脉北部和亚平宁山脉。东阿尔卑斯山和中部阿尔卑斯山部分地区的地震活动特别低。我们将一种聚类算法应用于焦点机制，考虑了现有目录中的其他机制。与N-S挤压体制有关，南阿尔卑斯山东部弗留里地区主要观察到东西向至ENE-WSW向的逆冲断裂。沿中央阿尔卑斯山北缘和迪纳里德山脉北缘观察到具有相似压力轴的走滑断裂。在西北和阿尔卑斯山观察到NW-SE走向的正断层，其走向与亚平宁地区的正断层地震相似。我们现有目录中的质心深度和震中深度都表明，阿尔卑斯山的地震活动主要是很浅的；大约80%的研究事件的深度小于10 Km。
Abstract. The Alpine mountains in central Europe are characterized by a heterogeneous crust accumulating different tectonic units and blocks in close proximity to sedimentary foreland basins. Centroid moment tensor inversion provides insight into the faulting mechanisms of earthquakes and related tectonic processes but is significantly aggravated in such an environment.
Thanks to the dense AlpArray seismic network and our flexible bootstrap-based inversion tool Grond, we are able to test different setups with respect to the uncertainties of the obtained moment tensors and centroid locations. We evaluate the influence of frequency bands, azimuthal gaps, input data types, and distance ranges and study the occurrence and reliability of non-double-couple (DC) components. We infer that for most earthquakes (Mw≥3.3) a combination of time domain full waveforms and frequency domain amplitude spectra in a frequency band of 0.02–0.07 Hz is suitable. Relying on the results of our methodological tests, we perform deviatoric moment tensor (MT) inversions for events with Mw>3.0. Here, we present 75 solutions for earthquakes between January 2016 and December 2019 and analyze our results in the seismotectonic context of historical earthquakes, seismic activity of the last 3 decades, and GNSS deformation data. We study regions of comparably high seismic activity during the last decades, namely the Western Alps, the region around Lake Garda, and the eastern Southern Alps, as well as clusters further from the study region, i.e., in the northern Dinarides and the Apennines. Seismicity is particularly low in the Eastern Alps and in parts of the Central Alps. We apply a clustering algorithm to focal mechanisms, considering additional mechanisms from existing catalogs. Related to the N–S compressional regime, E–W-to-ENE–WSW-striking thrust faulting is mainly observed in the Friuli area in the eastern Southern Alps. Strike-slip faulting with a similarly oriented pressure axis is observed along the northern margin of the Central Alps and in the northern Dinarides. NW–SE-striking normal faulting is observed in the NW Alps, showing a similar strike direction to normal faulting earthquakes in the Apennines. Both our centroid depths and hypocentral depths in existing catalogs indicate that Alpine seismicity is predominantly very shallow; about 80 % of the studied events have depths shallower than 10 km.
20世纪后亚得里亚海板块运动：来自周围造山带的新约束及其对壳幔脱钩的影响
影响因子：
4.2
作者：
Le Breton E;M.R. Handy;G. Molli;K. Ustaszewski
通讯作者：
K. Ustaszewski
影响因子：
--
作者：
S. Cesca;S. Heimann;K. Stammler;T. Dahm
通讯作者：
S. Cesca;S. Heimann;K. Stammler;T. Dahm
DOI：
10.2312/gfz.nmsop-2_is_3.9
发表时间：
2014
期刊：
影响因子：
--
作者：
F. Krüger
通讯作者：
F. Krüger