Abstract:In this paper, take two earthquakes for example. Tuosuohu's on Jan. 7,1937(M=7.5) and Gulang's on May 22, 1927(M=8.0)The anomaly of the length of seismic rupture belt is discussed with the concept of energy balance in fracture mechanics.
Such an anomaly of the length of rupture belt is of great importance in earthquake prediction. If the rupture belt is longer during a large earthquake, the same location can still be considered as a risk zone in the coming tens of years. In reverse, if the rupture belt is shorter, this region can be calm for quite a long period.

Abstract:This paper deals with earthquake sequence of magnitude over 7.0 in Tianshan region after 1900. It is shown by the M-T diagram that the earthquake activity of magnitude over 7.0 in Tianshan region is just the third activity period at present. The existence of linear trend is negated by the test. The testing result of the period of significance shows there are two periods which are 3 and 5 respectively when the test level is α=0.2. It has been done in this paper to have extrapolated prediction by these two periods, to verify the stability to the remained sequence and to have extrapolated prediction by higher autoregression model.

Abstract:Considering comprehensively the three factors of earthquake prediction(origin-time of earthquake, magnitude and epicentre), a model of fuzzy synthesis judgement has been used to evaluate the effect of a prediction, and the sequential test has been made for the synthetic judgement results of the predictions by using the sequential analysis of decision theory. Adopting this method of judgement, we can decide the efficiency of prediction method by the least times of prediction on average.

Abstract:For studying the relation between earthquake faulting and a pre-existing plane of weakness, the amphibolite samples were given special treatment. In the first group, the rock samples were sawed into two with the angles of 20°, 30°, 40°, 50°, between sawing plane and axial direction of the sample and then the two parts of the sample were adhered to each oth er with the epoxy resin. In the second and the third groups, the rock samples were sawed into tmo thirds and one third of the diameter of the samples respectively with the sample angles mentioned above, then were filled with the epoxy resin. The epoxy resin filled in the samples formed an artificial plane of weakness. The samples described above and the intact rock samples were tested under the confining pressures of 0.79k bars and 3.03k bars with constant strain rate of 10^-5 per second. It was found:
1. The process of fracture in the partly cutting samples consists of two major subfractures which followed one another closely. The first one is the fracture of the plane of weakness, the second one is a new fracture in rock;
2. The fracture in the samples which were cut through is along the plane of weakness completely. The fracture in most of the samples which wene cut into two thirds of its diameter developed along the plane of weakness but the fracture in the samples with cutting angles of 20° and 50° under confining pressnre of 3.03k bars is in the conjugate direction of the plane of weakness. All of the fractures in the samples which were cut into one third of its diameter pass through the end of cutting and most of them are in the conjugate direction of the plane of weakness, but the included angle, smaller.
3. The plane of weakness had obvious effect on the strength of the samples. The deeper the cutting, the lower the strength. The cutting angle also influences the strength of the samples which were sawed into two or into two thirds of its diameter, but there is no effect of the cutting angle on the strength of samples which were sawed into one third of its diameter.
By means of the results from the experiment, the relation was discussed between the earthquake faulting and the plane of weakness.

Abstract:This paper deals with the mechanism of earthquake precursors on the basis of the chemical composition of underground water by means of injecting water test at an oil field. The test was carried out in the way that we made 10 wells simutaneously impounded up to a depth of 800-1200m. The observed well selected for analysing chemical composition of water is a water-bearing bed with its depth of 50-300m. The water source has nothing to do with the water-bearing bed of the observed wells, The pressure on the water-bearing bed increases as the impounding goes down up to the depth of 800m. The force for preparing earthquakes from the lower strata acting on the water chemical composition has been simulated by means of transmission of the increased pressure.
The observed value indicates that the chemical composition of under ground water varies when the impounding pressure is transmitted up to upper water-bearing bed to cause stress-strain process. It is obvious that the variation amplitude is related to the well tectonic settings, and its geochemical surroundings, but scarcely to the distance of observed well and the testing water-injection well.

Abstract:In this paper, the quantitative research of sand and soal vibrating liquefaction potential is made with 2-dimentional information distribution concept and the formula of fuzzy approximate inferrence. Based on the data of sand and soil vibrating Iiquefaction potential collected by Japanese scholars, Kohji Tokimasu and Yoshiaki Yoshimi, at one hundred places all over the world, fuzzy relation (R)hasbeen established among stress ratio (τd/σ₀¹), normalized standard penetration test (N₁) and sand and soil vibrating liquefaction potential. The deta the author collected on 45 historical liquefaction spots are verified with this method and the results show that the rate of success accounts for 82 per cent of the total.

Abstract:Shanxi subsidence basin is an important area in North China, where strong earthquakes(M=6.0)always visit. This paper deals with the location of epicenters of the earthquakes, the isoseismal lines, the temporal sequences and the tectonic strike of all the strong earthquakes(M=6.0)in this area.
The following preliminary results can be done in this paper:
In the same subsidence basin, there are earthqakes of M=6.0 which occur repeatedly in the same spot with approximate magnitude, short interval, oblique or normal strike and the different kinds of seismogenic structure.

Abstract:The Kangding seismographic station is very close to the juncture of the three main fracture zones, named Xianshuihe River, Longmenshan Mountains and Anninghe River. In the past decade years, the metal horizontal pendulum clinometer has, to varying degrees, mirrored the earthquakes of M=5.5 within 200 km and of M=6.0 within 300 km, specializing in a few moderate strong quakes in Xianshuihe fracture zone. It seems that the station happens to be the sensitive soot for the precursors of inclination to be observed. At present, it is one of the most important measures to observe the inclination in Kangding seismographic station so as to monitor the seismicity in Sichuan Province.

Abstract:So far, the study on earthquake deformation band has not reached an identical view both at home and abroad. This paper, on the basis of enough data from practice and investigation, befines the kinds and names of deformation band, elucidating its properties in detail, analysing its mechanism of mechanics and expounding the relation between seismogenic fracture and deformation band, and the features of modern tectonic movement reflected by deformation band. Furthermore, in order to forecast the approaching strong earthquakes, the major geological signs are preliminarily summed up for strong earthquakes in the northwestern part of China.

Abstract:

Abstract:地震前天气特冷的现象,在17世纪华龙氏所著的震兆六端中就有论述。公元1830年6月12日河北磁县发生7.5级地震前也记到天冷似晚秋的气温状态,本文介绍1982年5月4日海南岛一次3.1级地震前的特低温现象,以供今后在研究地震预报指标时作参考。

Abstract:石咀山水氡观测点位于正谊关大断裂北翼的一条北东—南西走向的断裂带之上,断层岩性为前震旦片麻岩,泉水系花岗片麻岩中的裂隙水,以大气降水补给为主。

Abstract:对于余震的研究,包括时间序列和空间分布特征等方面,国内外一些作者已进行了大量的工作。一次强烈地震的发生,常常伴随着大量的余震,有些地震的余震活动延续几年甚至十几年,时有造成破坏的强余震发生。

Abstract:本文所指的甘孜地区是指我国四川省西北部甘孜高原西部的甘孜—马尼干戈断裂带、甘孜—理塘断裂带北段以及鲜水河断裂的北西段所展布的范围。

Abstract:1984年2月17日10点37分青海省祁连县东南(37°42'N,100°10'E)发生了5级地震(青海台网测定)。