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为计算１９８９ 年１０月１８日大同—阳高６．１级地震的震源参数，根据断裂力学的有关公式分析了断裂扩展过程中应力和位移的变化，利用弹塑性力学中的达格代尔（Ｄｕｇｄａｌｅ）模式塑性区中最大位移的公式计算了震源应力场的初始剪切应力τｏ 和地震释放的总能量ＥＴ；根据不同作者利用地震波资料和历史地震等烈度线所得出的不同震级的地震矩，利用最小二乘法拟合得出山西地区不同震级地震矩之间的关系，计算出大同—阳高６．１级地震的地震矩和其它震源参数。结果表明地震多数是在低初始应力作用下发生的（大约１００×１０５ Ｐａ左右），且与震级无关，主要决定于岩石的抗剪强度和断层面上的静摩擦力值；应力降的数值较小，大约在１０×１０５ Ｐａ～１００×１０５ Ｐａ之间，且与震级关系不大；地震释放的总能量比地震波释放的能量大一个数量级。指出利用断裂力学的有关公式计算震源应力场的初始剪切应力τｏ 和地震释放的总能量ＥＴ 在原理上是可行的，且方法简单；在缺乏地震波资料的情况下利用区域各物理量之间的统计关系计算某物理量同样是可行的，在方法上比利用地震波资料直接计算更简单。
In order to calculate the source parameters of the Datong-Yanggao MS6.1 earthquake on October 18, 1989, the changes of stress and displacement in the process of fracture propagation were analyzed according to the formulas of fracture mechanics. Based on the Dartdale Dugdale) model is used to calculate the initial shear stress τo of the source stress field and the total energy ET of the seismic release. Based on the seismic moments of different magnitudes obtained by authors using seismic data and historical seismic intensity lines, The least squares method was used to fit the seismic moment of different magnitudes in Shanxi Province, and the seismic moment and other source parameters of Datong-Yanggao M6.1 earthquake were calculated. The results show that most of the earthquakes occur under the low initial stress (about 100 × 105 Pa), and are independent of the magnitude, mainly due to the shear strength of the rock and the static friction on the fault plane. The value of the stress drop is small , About 10 × 10 5 Pa ~ 100 × 10 5 Pa, and has little to do with the magnitude; the total energy released by the earthquake is one order of magnitude larger than the energy released by the seismic wave. It is pointed out that using the formulas of fracture mechanics to calculate the initial shear stress τo of the source stress field and the total energy ET of the seismic release are feasible in principle and the method is simple. In the absence of seismic data, the statistics between the physical quantities in the area Relational calculation of a physical quantity is also feasible, the method is more simple than the direct calculation of seismic data.