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作者发现华北区现代地裂缝、历史地裂和黄土构造节理等松散土层破裂,与地震活动、地质构造、地貌和卫星象片等资料反映的现代地壳破裂网络一致。它们都是区域性构造应力场统一作用的产物。σ_1轴为NEE—SWW向的新构造应力场,控制了华北区断裂与地震活动;决定着松散土层破裂的系统性和区域性,是华北现代地震和地裂活动的主导因素。松散土层破裂特征表明,现今华北断块西部与南部因基底构造蠕滑在表土中主要产生蠕滑地裂缝;而其东部和北部因活断层速滑则主要发生强震,同时在表土层中出现有水平位移的地震断层和地裂缝。
The authors found that the modern earth fissures, the historical ground fissures, and the fractures of loose loess in the Loess tectonics in North China are consistent with the modern crustal rupture networks reflected by seismic activity, geological structure, landforms and satellite imagery. They are the product of the unified role of regional tectonic stress field. The σ_1 axis is a new tectonic stress field in the NEE-SWW direction, which controls faults and seismic activity in North China. It determines the systematic and regional rupture of loose soil and is the dominant factor in the modern seismic and ground fissure activities in North China. The characteristics of loose soil layer rupture indicate that the creep fissures mainly occur in the topsoil due to the basement structure creep in the western and southern parts of North China nowadays. Strong earthquakes occur mainly in the eastern and northern parts due to the active fault slippery, There are horizontal displacement of the earthquake fault and ground fissures.