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本文提出了一种矿山微地震震源函数反演的新方法。以球坐标系波动方程为基础,对时空域中的微地震观测信号进行层析成像投影到慢度时间域,我们可以获得微地震波成像能量最大值及其对应的震源位置、发震时间和传播速度以及慢度时间信号。通过分析能量最大值处的慢度时间信号与震源函数之间的关系,推导出了计算矿山微地震震源函数的层析成像公式和利用震源函数计算微地震有效辐射能量的公式。进一步利用最小二乘法,将震源函数的振幅谱拟合成模型震源谱,确定了微地震波的零频极限值和拐角频率,最终计算出该微震事件的震源破裂半径。利用这一方法对理论模型数据和实际资料处理,结果表明:本方法具有既能求出任意一个地震事件的震源位置、发震时间和传播速度,又能同时求出震源函数及其频率特征值和震源破裂半径等震源参数的优点,因此,本方法是一种实时快速计算方法。
In this paper, a new method of inversion of focal microseismic source function is proposed. Based on the wave equation of the spherical coordinate system, the microseismic observational signals in the space-time domain are projected onto the slowness time domain by tomography. We can obtain the maximum energy of microseismic imaging and its corresponding source location, the onset time and propagation Speed and slowness time signal. By analyzing the relationship between the slowness time signal and the source function at the maximum energy point, the tomographic formula for calculating the source function of the mine microseismicity and the formula for calculating the effective radiation energy of the microseismicity using the source function are deduced. The least squares method is further used to fit the amplitude spectrum of the source function to the model source spectrum. The zero-frequency limit and the corner frequency of the microseismic wave are determined. Finally, the source rupture radius of the microseismic event is calculated. Using this method, theoretical model data and actual data are processed. The results show that this method has the functions of finding the source location, the onset time and the propagation velocity of any one earthquake event, and simultaneously finding the source function and its frequency eigenvalue And focal source rupture radius and other source parameters, so this method is a real-time fast calculation method.