摘要
震级频度关系的Gutenburg-Richter公式近年来受到了挑战,一些学者在不同条件下都发现了b值的非线性表现。本文利用自己装配的实验系统对围压下岩石破裂声发射活动的震级频度关系和时间序列特征进行了研究。实验表明AE事件的震级频度关系在某个中强震级K′之前基本符合b值规律,其b值的大小与破裂方式有关。在摩擦滑动中AE序列具有低b值的特征。从K′起震级频度关系出现明显的非线性现象。根据非线性表现的不同,可将其分为第一型和第二型两类。在AE序列中,也存在着“特征震级”的现象。
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.
出处
《地震地质》
EI
CSCD
北大核心
1991年第1期54-60,共7页
Seismology and Geology
关键词
声发射
震级
频度关系
B值
Acoustic Emission, Magnitude-recurrence relationship, b-value, Characteristic earthquake
