美国大陆地区震中图的构造解释

TECTONIC INTERPRETATION OF THE EARTHQUAKE DISTRIBUTION IN THE CONTIGUOUS CONTINENT OF THE UNITED STATES

按照地震线的判定原则,利用美国大陆地区历史地震和现代地震的震中分布图,并结合地质和地球物理资料,画出了美国大陆地区的地震线和地震密集带,分析了美国大陆总体的和分区的地震构造格局特征,并与中国大陆的地震构造格局作了比较。结果说明,地震震中的空间分布特征反映了地壳内部活动构造的信息,大陆的地震构造格局不仅受原有构造格架和现今边界动力环境的控制,而且还可能受更高层次的全球构造动力因素的影响。

With increasing geological and geophysical data it becomes clear that seismicity of the continents is characterized by linear patterns which are closely associated with tectonic features. The aim of this paper is to give reasonable interpretation for the earthquake distribution in the contiguous continent of the United States. Seismic lines and earthquake concentrated zones reflect the characteristics of the continental seismotectonics. Similarities and differences in seismotectonics between the continental part of China and the contiguous continent of the United States are analyzed. It is demonstrated that the spatial distribution of earthquakes can provide information of the active structures in the earth crust. It is considered that the patterns of continental seismotectonics are not only controlled by the pre-existing tectonic frameworks and the current boundary conditions but also possibly by a global dynamic process.