关键词: 声发射, 震级频度关系, b值, 特征震级

Abstract: The Gutenburg-Richter law of magnitude-frequency relation has been challenged in recent years. Many researchers have found nonlinear sections in the magnitude-frequency relation in some cases. The magnitude-frequency relations shown in acoustic emission experiment of the rocks under confining pressures are studied in this paper.A new AE experiment system related to the confining pressure has been developed. The system can record the energy of AE events ranging from 1 to 10⁶ in relative energy unit.Six experiments of b-value simulation related to the confining pressure were conducted. The specimens were made of granite,marble,and granodiorite with different configurations. The main results of experiments are:1.The characters of acoustic emission of rocks are very similar with those of earthquake,providing the basis of applying AE experiment for the seismological research.2.The time series of AE events is fractally distributed on the time axis and its fractal dimension is a measure of AE activity.3.The AE series has not any characteristic occurrence period. The series of large AE events accords with neither the time-predictable model nor the slip-predictable model.4.There are two types of nonlinearity of b-value in the magnitude-frequency relations of either earthquakes or AE events.5.The magnitudes of AE events are fractally distributed on the magnitude axis. In addition,some problems aboul the theoretical study on b-value and applyingthe new method to seismological research have been discussed.

Key words: Acoustic Emission, Magnitude-recurrence relationship, b-value, Characteristic earthquake