Relation between the evolution of seismic apparent strain field and the region of strong earthquake occurrence

In this paper, according to the data on the middle and strong earthquakes in China, we have preliminary studied the relation between the characteristic of space-time evolution of the seismic apparent strain field and the regions of 31 macroseism events since 1955. The result shows that, there is a rather well correlation between the anomaly region of seismic apparent strain and the zone of macroseism event occurrence within the time range of one to about five years. The R value of the application of the abnormal region of seismic apparent strain to predicting the area of strong earthquake occurrence is 0.458, and the empirical possibility of forecasting the region of macroseism occurrence is 0.625, and so the forecasting effect is comparatively well. Finally, the main results obtained above are discussed preliminarily.

Corresponding Relation Between the Space-time Evolution of Seismic Apparent Strain and the Region of Strong Earthquakes in Yunnan

On the basis of our predecessors' research,we study the distribution and the space-time evolution characteristics of the seismic apparent strain field in Yunnan since the 1970's using the seismic data of Yunnan and its surrounding areas.The result shows that there is a rather strong corresponding relationship between the anomaly region of seismic apparent strain and strong earthquakes.In the nine earthquakes studied,anomaly areas of seismic apparent strain had appeared before eight earthquakes,including five occurring in the anomaly region and three on the edge.Finally,the investigative result is demonstrated primarily.

Aseismic negative dislocation model and deformation analysis of crustal horizontal movement during 1999--2001 in the northeast margin of Qinghai-Xizang block

Through numerical simulation for GPS data, aseismic negative dislocation model for crustal horizontal movement during 1999~2001 in the northeast margin of Qinghai-Xizang block is presented, combined with the spatial distribution of apparent strain field in this area, the characteristics of motion and deformation of active blocks and their boundary faults, together with the place and intensity of strain accumulation are analyzed. It is shown that: a) 9 active blocks appeared totally clockwise motion from eastward by north to eastward by south. Obvious sinistral strike-slip and NE-NEE relative compressive motion between the blocks separated by Qilianshan-Haiyuan fault zone was discovered; b) 20 fault segments (most of them showed compression) locked the relative motion between blocks to varying degrees, among the total, the mid-east segment of Qilianshan fault (containing the place where it meets Riyueshan-Lajishan fault) and the place where it meets Haiyuan fault and Zhuanglanghe fault, more favored accumulation of strain. Moreover, the region where Riyueshan-Lajishan fault meets north boundary of Qaidam block may have strain accumulation to some degree. c) Obtained magnitude of block velocities and locking of their boundaries were less than relevant results for observation in the period of 1993~1999.