Three-dimensional numerical modeling of contemporary mantle flow and tectonic stress beneath the earthquake-prone southeastern Carpathians based on integrated analysis of seismic, heat flow, and gravity data
Three-dimensional numerical modeling of contemporary mantle flow and tectonic stress beneath the earthquake-prone southeastern Carpathians based on integrated analysis of seismic, heat flow, and gravity data
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DOI：
10.1016/j.pepi.2004.08.012
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发表时间：
2005-03-15
影响因子：
2.3
通讯作者：
Schubert, G
中科院分区：
文献类型：
--
作者：
Ismail-Zadeh, A;Mueller, B;Schubert, G
本研究的主要目的是了解喀尔巴阡山脉东南部（弗朗西亚）的中深度大地震与高速体（岩石圈板块）下降到该地区地幔下引起的构造应力之间的相互作用。为了分析下降板块内部及其周围的应力生成过程和定位，我们建立了弗朗西亚地区当代地幔流动和应力的三维数值模型。模型的输入数据包括：(i)地震前纵波速度异常和地表热流的温度，（ii）从地震折射研究获得的纵波速度转换的地壳和上地幔密度，（iii）从层析成像和折射地震数据获得的弗朗西亚地壳和板块的几何形状，以及（iv）估计的板块应变率（由于地震）来约束模型粘度。研究发现，该模型预测的地壳隆升与东喀尔巴阡造山带重合，并围绕特兰西瓦尼亚盆地，预测的沉降区与莫西亚地台和东欧地台有关。我们显示了中深度地震的位置与最大剪应力的预测定位之间的相关性。模拟的构造应力预测在弗朗西亚地区下方约70-220公里的深度处会有较大的水平压缩，这与中深度地震的断面解所定义的应力状态相吻合。这表明弗朗西亚地区岩石圈板块的浮力下降与中深度地震活动直接相关。(c) 2004 Elsevier B.V.版权所有
The principal purpose of the study is to understand the interplay between intermediate-depth large earthquakes in the southeastern Carpathians (Vrancea) and tectonic stress induced by a high-velocity body (lithospheric slab) descending into the mantle beneath the region. To analyze processes of stress generation and localization in and around the descending slab, we develop a three-dimensional (3D) numerical model of contemporary mantle flow and stress beneath the Vrancea region. The input data of the model consist of: (i) temperatures derived front seismic P-wave velocity anomalies and surface heat flow, (ii) crustal and uppermost mantle densities converted from P-wave velocities obtained from seismic refraction studies, (iii) geometry of the Vrancea crust and slab from tomography and refraction seismic data, and (iv) the estimated strain rate in the slab (as a result of earthquakes) to constrain the model viscosity. We find that major crustal uplifts predicted by the model coincide with the East Carpathian orogen and surround the Transylvanian basin and that predicted areas of subsidence are associated with the Moesian and East European platforms. We show a correlation between the location of intermediate-depth earthquakes and the predicted localization of maximum shear stress. Modeled tectonic stresses predict large horizontal compression at depths of about 70-220 km beneath the Vrancea region, which coincides with the stress regime defined from fault-plane solutions for the intermediate-depth earthquakes. This implies that buoyancy-driven descent of the lithospheric slab beneath the Vrancea region is directly linked to intermediate-depth seismicity. (c) 2004 Elsevier B.V. All rights reserved.