Segmented seismicity of the Mw 6.2 Baladeh earthquake sequence (Alborz Mountains, Iran) revealed from regional moment tensors
Segmented seismicity of the Mw 6.2 Baladeh earthquake sequence (Alborz Mountains, Iran) revealed from regional moment tensors
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DOI：
10.1007/s10950-013-9362-7
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发表时间：
2013-04
影响因子：
1.6
通讯作者：
S. Donner;D. Rössler;F. Krüger;A. Ghods;M. Strecker
中科院分区：
文献类型：
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作者：
S. Donner;D. Rössler;F. Krüger;A. Ghods;M. Strecker
2004年5月28日，伊朗北方Alborz山区发生Mw6.2级地震。这次地震是这个陆内造山带中第一次有数字区域宽带数据的强震。Baladeh事件为使用现代地震学方法研究断层几何形状和正在进行的变形过程提供了难得的机会。联合反演震源和速度模型加上面波组频散曲线分析，以获得一个适应的速度模型，定制的中期和长期波形建模。基于新的速度模型，对主震和较大余震（Mw≥3.3）的区域波形资料进行了矩张量反演。对于Baladeh主震，这包括运动学参数的反演。所有分析的地震显示，在14和26公里之间的深度占主导地位的逆冲机制，与西北-东南走向断层面。主震沿北东方向破裂了一个28°南倾区，面积为沿着24 × 21 km。主震破裂面与余震分布不一致，无论是在地图上还是在深度上。考虑余震形成两个主要集群。东部星团与主震有关。西部的集群似乎并不与主震的破裂面相连，而是表明第二个活动断层面以85°向北倾斜。
TheMw6.2 Baladeh earthquake occurred on 28 May 2004 in the Alborz Mountains, northern Iran. This earthquake was the first strong shock in this intracontinental orogen for which digital regional broadband data are available. The Baladeh event provides a rare opportunity to study fault geometry and ongoing deformation processes using modern seismological methods. A joint inversion for hypocentres and a velocity model plus a surface-wave group dispersion curve analysis were used to obtain an adapted velocity model, customised for mid- and long-period waveform modelling. Based on the new velocity model, regional waveform data of the mainshock and larger aftershocks (Mw≥3.3) were inverted for moment tensors. For the Baladeh mainshock, this included inversion for kinematic parameters. All analysed earthquakes show dominant thrust mechanisms at depths between 14 and 26 km, with NW–SE striking fault planes. The mainshock ruptured a 28° south-dipping area of 24 × 21 km along a north-easterly direction. The rupture plane of the mainshock does not coincide with the aftershock distribution, neither in map view nor with respect to depth. The considered aftershocks form two main clusters. The eastern cluster is associated with the mainshock. The western cluster does not appear to be connected with the rupture plane of the mainshock but, instead, indicates a second activated fault plane dipping at 85° towards the north.