Some source and medium properties of the Vrancea seismic region, Romania
Some source and medium properties of the Vrancea seismic region, Romania
复制标题
罗马尼亚弗朗恰地震区的一些震源和介质特性
DOI：
10.1016/0040-1951(86)90231-3
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发表时间：
1986
期刊：
影响因子：
2.9
通讯作者：
M. Oncescu
中科院分区：
文献类型：
--
作者：
M. Oncescu
震源的简单谱理论被用来确定与Vrancea(罗马尼亚)地震区的介质性质(应力降、地震效率和破裂能量)和品质因子直接相关的震源参数。结果表明，最大静应力降、最大地震效率和断裂能随深度的增加而增大。地震效率与震级无关，但应力降仅对ML>；3.8级的地震是震级无关的；在此值以下，应力降的对数随震级准线性增加。在50-160公里深度范围内，应力降以2-3巴/公里的斜率增大。断裂单位面积的破裂能值在105-108erg/cm2数量级。频率无关品质因子表明，P波的衰减普遍高于S波，Qp值与Vrancea地区最新的构造模型一致：目前重力下沉的板块只在Vrancea地区的西南部存在完全解耦，由中深震源的空间位置所表明。
Simple spectral theory of seismic sources was used to determine source parameters directly related to medium properties (stress drop, seismic efficiency and fracture energy) and quality factors of the Vrancea (Romania) seismic region. The results show an increase in maximum static stress drop, maximum seismic efficiency and fracture energy with depth. The seismic efficiency is magnitude independent, but the stress drop is magnitude independent only for events withML> 3.8; below this value, the logarithm of stress drop increases quasi-linearly with magnitude. In the depth interval 50–160 km the stress drop increases with a slope of about 2–3 bar/km. The fracture energy per unit area of the fault has values of the order of 105–108erg/cm2.The frequency independent quality factors indicate that the attenuation of P waves is generally higher than that of S waves and thatQpvalues are in agreement with recent tectonic models for the Vrancea region: total decoupling of the slab now sinking gravitationally is present only in the southwestern part of the Vrancea region, as suggested by the spatial position of intermediate depth hypocenters.