The pattern characteristics of the tendency variations of earth resistivity and its relation to earthquakes

ＴｈｅｐａｔｔｅｒｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｔｈｅｔｅｎｄｅｎｃｙｖａｒｉａｔｉｏｎｓｏｆｅａｒｔｈｒｅｓｉｓｔｉｖｉｔｙａｎｄｉｔｓｒｅｌａｔｉｏｎｔｏｅａｒｔｈｑｕａｋｅｓＨｅ－ＹｕｎＺＨＡＯ（赵和云）（ＥａｒｔｈｑｕａｋｅＲｅｓｅａｒ...

The pattern characteristics of the tendency variations of earth resistivity and its relation to earthquakes

Through systematically summarizing the observational data of earth resistivity during 26 years from nearly a hundred stations in China, the author found that the pattern of the earth resistivity (ρ_s) tendency variations, based on monthly average data, could be divided into five types, three types of which were defined as anomalous variation, which have different qualitative and quantitative characteristics and different relations with earthquakes as well. The first type of tendency variation called “funnel” is related to strong earthquakes, the second type called “scoop” has good corresponding relation with moderate earthquakes, and the third type called “tilt” has no relation with earthquakes. Preliminary discussions about the relations between the three types of ρ_s tendency variation patterns and earthquakes are made in this paper, according to the experimental results of pressed rocks. It is concluded that the different patterns of ρ_s tendency variation actually reflect the different stress conditions of underground soil-rock layers: the “funnel” type reflects high stress status, the “scoop” type shows moderate stress condition and the “tilt” type is related to stress relief. All of such knowledges mentioned above are very useful in making accurate medium-term earthquake prediction.