Preliminary Study Of The Crustal Stress Field In Heilongjiang And Adjacent Areas

It is one of the core issues of earth dynamics in Crustal stress field study, manydomestic and foreign experts and scholars dedicated to itThe main task is: to discuss the tectonic stress field of the spatial distributionand its variation with time dynamic evolution, further tracing crust tectonic evolution,understanding today’s crustal tectonics and its mechanism, so as to predict the futureevolution of crust tectonic movement rules, and crustal stress field in theinterpretation of the motion of the plates, orogenic belt genesis of earthquake activitydistribution has important significance.This article from the basic concept of stress field, introduces the stress field force,vertical force and horizontal force is divided into two; also introduced the stress fieldof the time and space change, further elaborated the basic concept, focal mechanismsolution of earthquake fault and the basic concept of domestic and abroad this area ofresearch.Using the Heilongjiang and adjacent areas of5002P wave first motion, makethe composite mechanism, through integrated focal mechanism solution, launchedinHeilongjiang and adjacent areas of crustal stress field and that the direction of thestress field, through the above analysis and research, the study of regional tectonicstress field of the main features are as follows:1、 The new century to the modern tectonic stress field characteristics areconsistent, with obvious inheritance. Main pressure stress orientation and maintectonic belt and mechanical properties of basic stability. Principal stress direction isNorth East-nee, under its control within the region of the NNE fault is dextralstrike-slip normal fault.2、 The tectonic stress field of the horizontal component is the main.Performance in new tectonic activity features and focal mechanism solution,especially the focal mechanism solutions of principal stress angle less than30degrees accounted for about80%, the vast majority of steep dip of fault surface, along the faultdislocation angle less than30degrees are accounted for90%of the total.3、The tectonic stress field and the motion of the plates with the relationship ofcontact. This article has described the front new tectonic period since theHeilongjiang were embroiled in intense activity in the marginal Pacific tectonicdomain, the tectonic stress field is by the Pacific plate to Eurasia plate subductionforming. In the North East under the extrusion, the province formed a series of NNE,NE, near east to west and north to the normal fault and reversed fault. In the NorthEast regional stress field, the NNE and North East fracture tectonic belt movement forthe dextral strike-slip fault, North and west fault tectonic belt and nearlyeast-westward fault structural belt is sinistral strike-slip fault mainly.