广西南丹大厂矿区震源参数研究

利用广西南丹县大厂矿区地震监测台网记录的地震波资料,采用Brune（1970）模型,将速度记录谱归算为震源位移谱,使用遗传算法计算拐角频率及零频极限,然后计算地震矩、应力降等小震震源参数,并系统分析各种参数之间的关系。大厂矿区38次较大地震的震源参数计算结果为：地震矩范围在2.18×1011~7.89×1012 N·m之间;震源破裂半径78~439m;地震应力降在0.01~1.79 MPa之间。表明：地震矩与震级、震源半径、拐角频率之间呈线性关系,而应力降不依赖于地震矩,分布较为离散。大厂矿区应力降值明显偏低,这可能与该区域背景应力低有关。

Study on Source Parameters of Earthquakes in Dachang Mining Area

Using the Brune model （1970） and the digital seismic wave data of the earthquake occurred in Dachang mining area, which was recorded by Guangxi Dachang seismic network; we transferred the veloci- ty spectrum into source displacement spectrum. The corner frequency and zero frequency were calculated by using genetic algorithm, further, the source parameters including seismic moment and stress drop were calculated and the relationships among them were analyzed systematically. This paper studies 38 bigger re- gional earthquakes occurred in this area, the results show that they seismic moments are 2.18X 1011 ~7.89 ）〈101ZNomand rupture radius are 78~439 m, stress drop are 0.01~1.79 MPa. The relations between seismic moment, body-wave magnitude, rupture radius and corner frequency are near log-linear. The distri- bution of stress drop is dispersed and show little obvious correlation with seismic moment. Dachang mining stress drop values significantly lower, this may be related to the low regional background stress.