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本文从部分地球物理资料出发,初步探讨了中国南北地震带北段(贺兰山—六盘山地震带)、中段(天水—武都、文县—川西北地震带)地壳和上地慢的结构特征。 根据对有关资料的分析研究,初步得出中国南北地震带北段、中段深部地震环境的主要特点: 地震带下部的上地幔顶面呈带状隆起:银川地堑地区上地幔顶面带状隆起的轴向呈北北东向;西吉、海原、固原地区呈北西向;天水—武都地区呈近南北向。 强烈地震的断层走向、震中迁移方向与软流圈顶面等深线轴向方向一致。 强烈地震往往发生在深部构造与浅部构造在深部的交汇区,如天水、武都地区。 强烈地震与壳内高导层和上地幔高导层的局部隆起和拗陷有关。 进而尝试性的分析了深部环境与地震孕育发生的关系。最后文章讨论了深部地震环境对中长期地震预报和地震成因研究的意义。
Based on some geophysical data, the paper first explores the structural features of the crust and upper slow in the northern section of the North-South Seismic Belt (Helan Mountain-Liupan Mountain seismic belt) and in the middle section (Tianshui-Wudu, Wenxian-Northwest Sichuan Seismic Belt). According to the analysis of relevant data, the main characteristics of the deep seismic environment in the north and the middle of the North-South Seismic Belt are preliminarily obtained: the top of the upper mantle in the lower part of the seismic belt is ribbon-shaped uplift; the top of the upper mantle in Yinchuan-graben zone is ribbon- The north and south directions of Xiji, Haiyuan and Guyuan belonged to northwest direction, while that of Tianshui-Wudu region was nearly north-south direction. In the strong earthquake, the strike of the fault and the migration direction of the epicenter coincide with the axial direction of isobath of the asthenosphere. Strong earthquakes often occur in deep intersections of deep structures and shallow structures, such as Tianshui and Wudu areas. The strong earthquakes are related to the local uplift and depression of the high conducting layer in the crust and the upper mantle. And then tentatively analyzed the relationship between deep environment and earthquakes. Finally, the paper discusses the significance of deep seismic environment to medium and long term earthquake prediction and earthquake genesis.