华北北部构造应力场
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摘要
本文根据震源机制、原地应力测量、小震应力降和形变测量等资料，结合有限元数值计算的结果，研究了华北北部（东经１１４°─１１７°，北纬３９°─４１°）的构造应力场特征，并根据库仑剪切破裂准则，进一步研究了强震危险区的应力标志。结果表明，强震危险区的应力标志是：（１）最大剪应力相对集中的高值区；（２）围压相对较小的引张区；（３）发震断裂走向与临界走向断裂的走向相同或相近。据此，综合判定研究区未来的强震危险区主要有４个，若依危险程度的大小顺序排列，则是：（１）怀安－化稍营危险区；（２）怀来－涿鹿危险区；（３）广灵－灵丘危险区；（４）怀柔－大兴危险区。
Based upon the data on focal mechanisms, stress measurements in situ, stress drop of small earthquakes and deformation measurements, in this paper the characteristics of the tectonic stress field in the northern part of North China (114°─117°E, 39°─41°N) are studied synthetically, and according to the Coulomb shear fracture criterion, the stress marks of strong earthquake risk zone are further studied. The results show that the main marks of strong earthquake risk zone are: (1) the relative high-value zone of the maximum shear stress, (2) the tensile area of a rather small confining pressure, and (3) the strike of seismic fault being about the same as the strike of critical strike fault. In accordance withthese marks, it is inferred that there are mainly four strong earthquake risk zones in the northern part of North China in the future, and if we arrange according to the number of satisfied stress marks or the order of possibility of earthquake occurrence, the location of a coming earthquake would be: (1) Huai'an-Huashaoying risk zone, (2) Huailiai-Zhuolu risk zone, (3) Guangling-Lingqiu risk zone, and (4) Huairou-Daxing risk zone.
Based upon the data on focal mechanisms, stress measurements in situ, stress drop of small earthquakes and deformation measurements, in this paper the characteristics of the tectonic stress field in the northern part of North China (114°─117°E, 39°─41°N) are studied synthetically, and according to the Coulomb shear fracture criterion, the stress marks of strong earthquake risk zone are further studied. The results show that the main marks of strong earthquake risk zone are: (1) the relative high-value zone of the maximum shear stress, (2) the tensile area of a rather small confining pressure, and (3) the strike of seismic fault being about the same as the strike of critical strike fault. In accordance withthese marks, it is inferred that there are mainly four strong earthquake risk zones in the northern part of North China in the future, and if we arrange according to the number of satisfied stress marks or the order of possibility of earthquake occurrence, the location of a coming earthquake would be: (1) Huai'an-Huashaoying risk zone, (2) Huailiai-Zhuolu risk zone, (3) Guangling-Lingqiu risk zone, and (4) Huairou-Daxing risk zone.
引文
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