国外某些地震区大地震孕育过程分析(Ⅰ)

Analysis on the seismogenic processes of large or great earthquakes for some seismic zones abroad based on the brittle failure theory of multiple locked patches (Ⅰ)

在缺失断层资料、无法准确厘定地震区边界的情况下,本文提出了地震区划分的合理性判别原则与＂最优地震区＂确定方法.从孕育周期界定与主震事件判识角度,分析了7个国外地震区强（大、巨）震孕育过程,阐述了该方法的实际操作步骤.震情分析表明：意大利中部地震区和泰缅边境地震区未来有强震发生;海地-多米尼加-波多黎各地震区未来有大震发生;巴基斯坦-阿富汗-伊朗地震区未来将发生MW7.9~8.1级地震;对涉及深源地震的堪察加地震区、南美洲西部地震区和日本地震区,分考虑和不考虑深源地震两种情况,分析了上述三个地震区大（巨）震事件的孕育过程,给出了其未来巨震事件的四要素预测结果.研究表明：考虑深源地震与否,对于孕育周期起点与终点、膨胀点与峰值强度点标志性地震事件的选择、预测临界CBS值以及未来震情的判断都有一定影响,特别是在深源地震本身就是膨胀点或峰值强度点标志性事件的情况下其影响更加显著.因此,对深源地震成因机制的研究有待进一步深入,以期给出其是否参与孕震过程的明确依据.

With the absence of fault information,the recognition principle for the rational division of seismic zone and the division method of the optimal seismic zone were proposed by us.Meanwhile,through the new insights into the definition of seismogenic period and the recognition of the main shock event,the seismogenic processes of seven seismic zones abroad were analyzed in order to demonstrate the practical steps of the method above.The results suggest that strong earthquakes will occur in the central Italy seismic zone and the Thailand-Burma border seismic zone respectively,a major earthquake will occur in the Haiti-Dominican republic-Puerto Rico seismic zone and an earthquake of MS 7.9~8.1 will occur in the PakistanAfghanistan-Iran border seismic zone.For the other three seismic zones involving the deep focus earthquakes,the seismogenic processes were analyzed with considering the deep focus earthquake or not.The results indicate that major or great earthquakes will occur in the Kamchatka seismic zone,the western South America seismic zone and the Japan seismic zone respectively. Meanwhile the prediction results of the future great earthquakes in the three seismic zones above,including the magnitude,place,critical strain,and hypocentral depth,are also presented.Moreover,it was found that deep focus earthquakes have a great influence on the choices of the starting point and endpoint of the seismogenic period,the identifications of the symbolic earthquake magnitude at the volume expansion point and peak strength point of the locked patches,the calculation of critical accumulative Benioff strain（CBS）and the judgment of future earthquake situation.Therefore,the further study on the mechanism of deep focus earthquake was still needed in order to reveal the effect of the deep focus earthquake in the process of seismogenic process.