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本文推导了各类点源和线源(压性、张性、压扭性、张扭性、单力偶和双力偶)的理论地震位移场公式,讨论了板内地震的震源力学性质.根据实测地震位移场、建筑物破坏和倒塌的优势方向等近场资料与理论结果对比,作者认为,1966年邢台地震震源机制符合于张性断裂的模型;1966年东川地震震源机制符合于压扭性断裂的模型.根据理论公式和实际位移资料,给出了邢台地震的地震矩 M_0为6.5×10~(26)达因·厘米,应力降△σ为39巴.最后指出大地震的震源力学机制反映了该区域长期构造应力作用的状态,认为双力偶(剪切位错)不一定是板内地震震源机制的最合适的、唯一的模型.
In this paper, the theoretical formula of displacement field for point sources and sources (pressure, tension, compression, tension, single couple and double couple) is deduced, and the source mechanical properties of the intraplate earthquake are discussed. The authors believe that the focal mechanism of the Xingtai earthquake in 1966 accords with the model of Zhang-Zhang fault. The focal mechanism of the Dongchuan earthquake in 1966 accords with the compressive-torsional According to the theoretical formula and actual displacement data, the seismic moment M_0 of Xingtai earthquake is 6.5 × 10 ~ (26) dyne cm and the stress drop △ σ is 39 bar.Finally, the focal mechanism of the earthquake is pointed out Reflecting the state of long-term tectonic stress in the region, it is considered that the dual couple (shear dislocation) is not the most suitable and unique model for the focal mechanism of intraplate earthquakes.