贵州主要活动构造体系与地震

The principal active tectonic systems in Guizhou and earthquakes

晚期新华夏系的北北东与北东东向断裂在輓近地质时期最为活跃,是孕震和发震的主要构造,大部中强地震的震中位于这两组断裂附近,尤其是北东东向的扭压性断裂,几乎切割了早期所有构造体系和构造带,与地震密切相关。贵州省境的大部地震,尤其是中强地震,发生于东经106°以西地区。晴隆—兴仁—册亨及威宁—石门两带为重点震区。另外,有些历史上曾发生过地震而近年又有小震发生的活动断裂带及断陷盆地,显示断裂活动的潜力在增强。上述地区,应予重点监测。

The exposed rocks from the late Proterozoic Era to the Quarternary Period are distributed aliover Guizhou province and their total thickness is more than 20,000m. They have undergone many stages of tectonic movements and reveals various distinguishing features with complicated tectonics, strong folds, fault blocks and rifts crossed and the multiformity of tectonic patterns. In the tectonic systems and belts devided by their origin times and features, the Neocathaysian system is the most frequently active system in late gelolgical times (i. e. from the Tertiary Eocene epoch to present) and can almost be found all over the province. It is the principal tectonic system to be resarch for deformation of the Cenozoic group, terrain relief, terrestrial heat and tectonic earthquakes. The Neocathaysian tectonic system is fallen into early Neocathaysian system and late Neocathaysian system. The north-northeast and northeast-east faults ofthe latter are more active in late geological times, they are the main structures of earthquake pregnancy and occurrence, most epifocuses of moderate strong earthquakes are near the two fault groups which almost cut all early tectonic systems and belts and have close relationship with eaxthquakes, particularly the northeast—east shear—pressure faults. Most earthquakes in Gnizhou privince, particularly the moderate strong earthquakes, occurred in area west of long. 160° E, The zones of Qinglung-Zingren—Ceheng and Weining-Shimen are the main earthquake areas. In addition, some active fault zones and fault depression basins which occur- red earthquaces historicallyagain occurredsmallearthquakesin recent years, it suggests that the potential of fault activity is enhancing. We should give more effective monitoring to above Zones and areěas.