关键词: 震源机制, 地壳应力场, 地震断层错动性质, 华东地区

Abstract: Statistic analysis has been made on the characteristics of the contemporary tectonic stress field of East China based on 143 sets of single focal mechanical solutions of moderate and small earthquakes and on 17 sets of composite focal mechanism solutions. Results show that the stress field of East China exhibits a NNE (about 80?) oriented principal compression and NNW (about 350?) principal tension, and the principal stresses are mainly horizontal or near-horizontal. In the context of basically consistent orientation and action mode of stress field, there are some variations in the stress field among different seismotectonic regions, which are possibly related to the distribution of major active faults in the respective regions. This indicates that fault slip may be dominated or affected by existing tectonics. The feature of earthquake fracture and the orientation of fault slip of contemporary earthquakes in East China have been analyzed with data of focal mechanism solutions of contemporary moderate and small events, and of the orientations of major axis for innermost isoseismal of historical and contemporary events and so on. It indicates that the earthquake fractures of East China extend at large in NE and NW directions, and sometimes with NNE, NEE, NWW, or near EW directions. The movements of earthquake faults are mainly of strike-slip or near strike-slip with oblique-slip component. There exist some regional variations in the movement of earthquake faults. The historical moderate and strong events in East China exhibit mainly a NE trending slip, while the modern events show the NW-SE trending slip on the land and NE and NW trend slip in the sea area.

Key words: focal mechanism solutions, crustal stress field, feature of earthquake fault slip, East China