岩石破裂过程中电磁辐射信号特征研究

为了探索震前电磁异常现象的物理机制,许多研究注重于分析岩石破裂过程中产生的电磁辐射信号。对花岗岩样品进行单轴加载,变形直至破裂,记录整个过程中产生的电磁辐射(EME)和声发射(AE)信号,对比分析。这里主要从两个方面分析岩石破裂过程中EME信号的特征:①利用非广延分析方法分析EME的能量分布情况,并与b值分析方法对比,推断岩石破裂类型以及裂纹发育过程;②利用统一等待时间定标律分析EME的时间特征,期望获得岩石破裂过程中EME信号等待时间的分布规律。结果表明,在拟合AE和EME信号的能量分布曲线时,发现b值只能拟合AE部分数据,完全不能拟合EME数据,而非广延参数q可以很好地拟合这两类信号。通过对比分析AE和EME信号的等待时间概率密度的分布情况,发现EME信号的集成效果相对较差,可能不满足统一等待时间定标律。

Study on the signal characteristics of electromagnetic emission during rock fracture

In order to explore the physical mechanism of the anomalous electromagnetic emissions observed before earthquakes,many studies have focused on the analysis of electromagnetic emissions produced during rock fracture.Granite samples under uniaxial loading underwent deformation until its fracture,we recorded and comparatively analysed the electromagnetic(EME)and acoustic emission(AE)signals produced during the whole loading process.This paper mainly analyzes the characteristics of EME signals from two aspects:(1)the energy distribution characteristics of EME signals was analysed with non-extensive analysis method and comparing it with b-value analysis method,so that we may infer the type and the development process of rock fracture;(2)the time characteristics of EME signals was analysed by using unified scaling law for waiting time,and we expect to get the distribution law of the waiting time of EME signals during rock fracture.The result shows that b-value fitting method can only match the part of AE signal and it's almost impossible to match the EME signal when fitting the energy distribution curves of the AE and EME signals,but these two kinds of signal can be well fitted with non-extensive parameter q.By comparing and analyzing the probability density distribution for the waiting time of the AE and EME signals,it is found that the integration effect of EME signals is relatively poor,which may not meet the unified scaling law for waiting time.