用数值模拟方法评估华北北部地震危险性
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摘要
根据华北北部地区深浅部地质特征建立地质模型，采用含位错面的三维粘弹性有限单元方法，在反演断层深部滑动速率的基础上计算区域内有效应力和应变能密度随时间的变化。由数值模拟结果估计华北北部的地震危险性，提出了 ３ 个潜在震源区：张家口及以北地区，震级上限为 ６ 级，孕震层在上地壳下部；延怀盆地，震级上限为 ７ 级，孕震层在中地壳；阳原盆地，震级上限为６ 级，孕震层在下地壳上部
Based upon the deep and shallow geological features of northern North China area(39～41°N,114～117°E), a tectonic model is established. With this model the effective stress, the strain energy density and their variations with time are calculated using the 3 D viscoelastic finite element method containing dislocation plane.Deep slip rates of several major active faults are inversed by the dislocation inverse method to provide boundary conditions for the calculations. From the results of modeling, three different potential earthquake areas are proposed : M 6 in Zhang jiakou and its north at upper crust, M 7 in Yanqing and Huailai basin at middle crust, and M 6 in the Yangyuan basin at lower crust.
Based upon the deep and shallow geological features of northern North China area(39～41°N,114～117°E), a tectonic model is established. With this model the effective stress, the strain energy density and their variations with time are calculated using the 3 D viscoelastic finite element method containing dislocation plane.Deep slip rates of several major active faults are inversed by the dislocation inverse method to provide boundary conditions for the calculations. From the results of modeling, three different potential earthquake areas are proposed : M 6 in Zhang jiakou and its north at upper crust, M 7 in Yanqing and Huailai basin at middle crust, and M 6 in the Yangyuan basin at lower crust.
引文
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宋惠珍,黄立人,华祥文. 1990. 地应力场综合分析. 北京∶石油工业出版社.
宋惠珍,兰印刚,徐鹏飞, 等. 1995. 1303 年洪洞 8 级地震震源过程研究. 地震地质,17(1):13～24.
宋惠珍,刘洁,兰印刚. 1993. 位错模型的有限单元公式. 西北地震学报,15(1):6～12.
Harris R A, Segall P. 1987. Detection of a locked zone at depth on the Parkfield, California, Segm ent of the San Andreasfault. J Geophys Res, 92( B2): 3745～3762.
Jungels P H. 1973. Models oftectonic processes associated w ith earthquakes:[ Dissertation]. Pasadena: California Instituteof Technology.
Melosh H J, Raefsky A. 1981. A sm iple and efficient m ethod for introducing faults into finite elem ent com putations. B S S A, 71(5):1391～1400.
Okada Y. 1985. Surface deform ation due to shear and tensile fault in a halfspace. B S S A, 75(4):1135～1154.
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