The anomalous time of underground water precursors in the focal area which was ohrained by using the equations developed by whitcomb and Nut similar to above mentioned abnormal time.

The characteristics of anomaly for earthquake group mainly are: (1) the temporal span of anomaly is large, and the anomaly, which behaves tendency anomaly, generally run through the whole earthquake group;

It is meaningful that these theoretical results have been applied to explain preliminarily the characteristics of stage variation of spatial temporal evolution, the pattern and quadrant distribution of earthquake precursors, the changeability, spontaneity and complexity of short term and imminent term precursors.

(3) The theoretical results have been applied to explain tentatively follow questions; the stage variety of the spatial temporal evolution, shape and quadrant distribution characteristics of earthquake precursors, spontaneity, variety and relativity with external agencies of immediate precursors and so on.

In this case the uplifted area had a radius of approximately 200 km, and the precursor time may have been about 30 years.

It is demonstrated that the precursor time interval (τ) vs.M relation approximately fits in that for the τ vs.

The precursor time observed 9±1.5 years is in fairly good agreement with current magnitude-precursor time relations.

Empirical relations are given between earthquake magnitude and the epicentral distance of the farthest groundwater anomaly, and between earthquake magnitude and the precursor time of groundwater.

It is obviously impossible to demonstrate in this study whether or not there is any relation between precursor time and earthquake magnitude.

Based upon the statistical analysis of the groundwater anomaly before Haircheng earthquake with magnitude 7.3. it can be found that the abnormal time before the earthquake have a varied tendency as arithmetic series progressively of decrease. The anomalous time of underground water precursors in the focal area which was ohrained by using the equations developed by whitcomb and Nut similar to above mentioned abnormal time. Thus it can suggest that the anomaly time of earthpuake precursors controlled bythe identical...

Based upon the statistical analysis of the groundwater anomaly before Haircheng earthquake with magnitude 7.3. it can be found that the abnormal time before the earthquake have a varied tendency as arithmetic series progressively of decrease. The anomalous time of underground water precursors in the focal area which was ohrained by using the equations developed by whitcomb and Nut similar to above mentioned abnormal time. Thus it can suggest that the anomaly time of earthpuake precursors controlled bythe identical focus in the focal area and its surrounding region are consistent what their gener regardless of nature and process of precursors. This idea will provide a basisfor studing the quantitative marker oral of anomaly time bafore an earthquake in future.

The direct method of fuzzy pattern recognition has been applied to the synthetic recognition of medium-short-term (several months) earthquake precursors of different kinds observed at different stations.The basic technique of this method is to construct a suitable membership function for each single precursor at each single station and then the comprehensive membership function for several precursors of different kinds or for the same precursor observed at different stations.By using this method,the precursors...

The direct method of fuzzy pattern recognition has been applied to the synthetic recognition of medium-short-term (several months) earthquake precursors of different kinds observed at different stations.The basic technique of this method is to construct a suitable membership function for each single precursor at each single station and then the comprehensive membership function for several precursors of different kinds or for the same precursor observed at different stations.By using this method,the precursors observed in the Tokai area and its vicinity of Japan are studied with emphasis. They are the radon content in ground water,groundwater level,tilt,tide and volume strain. The abundant observational data from 3 tilt stations,2 tide stations,2 stations for observation of radon content in ground water,2 stations for observation of water level and 30 stations for observation of volume strain are used. Two possible precursor patterns for medium-short-term earthquake prediction in the Tokai area were proposed. One is applied to the synthetic analysis of several precursors of different kinds and at different stations,the other is applied to the synthetic analysis of one-kind of precursor (volume strain) observed at different stations.For comparison,the result of synthetic recognition of medium-short-term precursors of radon content in ground water at many stations before the great M = 7.8 Tangshan earthquake of 1976 and its M = 6.9 strong aftershock observed in the Beijing-Tianjin-Tangshan area and its vicinity of China is introduced. The precursor pattern obtained corresponds to the second precursor pattern for the Tokai area of Japan.

Based on the analysis of precursory anomalies of some strong earthquake (Ms>>>>>>7.0) cases in China Mainland, this paper illustrated the large-scale characteristics of the time-space distribution of strong earthquake precursors in China Mainland: (1) the precursory field of strong earthquakes and the affected field after earthquakes are vast, which might extend all over China Mainland; (2) the abnomal time of some precursors is longer, which may be related with several strong earthquakes, even some leap over...

Based on the analysis of precursory anomalies of some strong earthquake (Ms>>>>>>7.0) cases in China Mainland, this paper illustrated the large-scale characteristics of the time-space distribution of strong earthquake precursors in China Mainland: (1) the precursory field of strong earthquakes and the affected field after earthquakes are vast, which might extend all over China Mainland; (2) the abnomal time of some precursors is longer, which may be related with several strong earthquakes, even some leap over the 4th seismic high-tide period (1966-1976) in China Mainland since this century. In addition, before strong earthquakes, the precursory anomalies occurred throughout China Mainland are relatively concentrated at the shortimpen-ding stage, formed an anomalous peak value, and some precursory anomalies are of obvious coseismic effect features. The region where the coseismic effect anomalies occur will probably be the causative area of future earthquakes. According to this, we proposed the "China-Mainland comprehensive precursory method", for earthquake prediction.