In the moment-ratio imaging algorithm,which is based on the theory of healing of a wound,the energy of each strong earthquake is distributed around the epicenter according to certain rules,and the features of the Mo-ment-ratio value R are analyzed as the space and time change,so that the relationships between the moment-ration value R and strong earthquakes can be found. In the present paper,regions divided,hypocenter depths and events completed magnitude analyses were carried out in the Chinese catalogue. By applying the moment-ratio imaging algorithm in which the parameters are adjusted,the processes of anomaly evolution which correspond to the epi-center and the surrounding value R before earthquakes of M≥7.0 since 1966 in different areas of China were ana-lyzed. It was found that the range area and imminent time of a coming earthquake could be confirmed quantita-tively by analyzing the abnormal temporal and spatial variation of the value R. The results showed that the tempo-ral and spatial variation of the value R could quantitatively reflect the temporal and spatial factors of a coming strong earthquake as well as the rule of medium rupture.
Many factors can cause changes of groundwater level,such as the development process of an earthquake,rainfall,solid earth tides etc.Among these we are interested in information regarding earthquake development processes.Eliminating the influence of various disturbance factors is an effective way to obtain seismic development process information contained in the groundwater level.This paper provides two different ways to remove the rainfall effect,and compares the two methods by means of correlation analysis.Furthermore,based on these a logistic regression model is established to describe the seismicity level.
In Capital Circle area, there are three groups of repeated gravity measurements observed by different institutes using different instruments or methods. The simultaneous adjustment of absolute and relative measurements and the elimination of systematic error among the relative measurements have been carried out in this paper. Thus an unified temporal gravity change system with absolute reference has been established. On the basis of this, the crustal subsidence effect on gravity, which belongs to non-tectonic factor, is analyzed and the station displacement corrections are carried out, so that the long-wave disturbance is eliminated. So far our following aims are realized: the advantages of the absolute and relative measurement methods are complementary to each other; the contradic- tion and environment disturbance are eliminated; the amounts of information are enlarged; the sampling interval of time domain is compressed. In a word, the ability of identifying the tectonic activity process is enhanced. The re- sults show that: there are systematic errors between the two groups of relative measurements and within the data of 10 campaigns ; the uneven local crustal subsidence in the southeast of the study area results in a linear rise of grav- ity value at 10 stations; they can be corrected by the regression analysis. The maps of revised temporal gravity change can obviously and integrally reflect the MS=5.0 earthquake in Guye on October 6, 1995.
