Moment release in the Lower Rhine Embayment, Germany: seismological perspective of the deformation process
Moment release in the Lower Rhine Embayment, Germany: seismological perspective of the deformation process
复制标题
德国莱茵河下游海湾的力矩释放：变形过程的地震学视角
DOI：
10.1111/j.1365-246x.2005.02525.x
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发表时间：
2005
影响因子：
2.8
通讯作者：
K. Hinzen
中科院分区：
文献类型：
--
作者：
J. Schmedes;S. Hainzl;S. Reamer;F. Scherbaum;K. Hinzen
总结
地震矩释放率的估算是地震危险性评价的一项重要任务，它与构造变形速率和地震耦合有关。然而，对变形的估计取决于所使用的信息类型（例如大地测量、地质、地震），并包括很大的不确定性。因此，我们估计变形率在下莱茵河Embayment（LRE），德国，使用一个综合的方法，系统地纳入了不确定性。在新的齐次地震目录的基础上，用统计方法初步确定了频度-震级分布。特别是，我们专注于一个足够的古腾堡-里希特关系的上限估计，并证明了额外的古地震信息的重要性。地震学和地质信息的综合产生了上限震级的概率分布。使用该分布以及古腾堡-里希特a和B值的分布，我们进行蒙特卡罗模拟以推导出地震矩释放随观测时间的变化。从短目录长度的合成地震目录估计的地震矩释放被发现系统地低估了可以分析确定的长期矩率。在过去的250年里，在LRE记录的时刻释放被发现是在很好的协议从蒙特卡洛模拟的概率分布。此外，长期分布是在其不确定性与地质测量得出的矩率一致，表明在这个地区几乎完全地震耦合。借助于Kostrov公式，我们还利用LRE中已知的震源机制分布计算了全形变率张量。最后，我们使用相同的方法来计算地震矩和变形率的两个子集的目录对应的东，西倾断层，分别。
SUMMARY
An important task of seismic hazard assessment consists of estimating the rate of seismic moment release which is correlated to the rate of tectonic deformation and the seismic coupling. However, the estimations of deformation depend on the type of information utilized (e.g. geodetic, geological, seismic) and include large uncertainties. We therefore estimate the deformation rate in the Lower Rhine Embayment (LRE), Germany, using an integrated approach where the uncertainties have been systematically incorporated. On the basis of a new homogeneous earthquake catalogue we initially determine the frequency–magnitude distribution by statistical methods. In particular, we focus on an adequate estimation of the upper bound of the Gutenberg–Richter relation and demonstrate the importance of additional palaeoseismological information. The integration of seismological and geological information yields a probability distribution of the upper bound magnitude. Using this distribution together with the distribution of Gutenberg–Richter a and b values, we perform Monte Carlo simulations to derive the seismic moment release as a function of the observation time. The seismic moment release estimated from synthetic earthquake catalogues with short catalogue length is found to systematically underestimate the long-term moment rate which can be analytically determined. The moment release recorded in the LRE over the last 250 yr is found to be in good agreement with the probability distribution resulting from the Monte Carlo simulations. Furthermore, the long-term distribution is within its uncertainties consistent with the moment rate derived by geological measurements, indicating an almost complete seismic coupling in this region. By means of Kostrov's formula, we additionally calculate the full deformation rate tensor using the distribution of known focal mechanisms in LRE. Finally, we use the same approach to calculate the seismic moment and the deformation rate for two subsets of the catalogue corresponding to the east- and west-dipping faults, respectively.