| 流变介质中亚临界扩展前地震孕育过程的能量积累 |
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| 引用本文： | 滕春凯,白武明,王新华.流变介质中亚临界扩展前地震孕育过程的能量积累[J].地球物理学报,1991(1). |
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| 作者姓名： | 滕春凯 白武明 王新华 |
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| 作者单位： | 中国科学院地球物理研究所，中国科学院地球物理研究所，国家地震局地球物理研究所 北京 100101，北京 100101，北京 100081 |
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| 摘 要： | 本文用流变断裂力学研究了地震孕育过程.与弹性力学不同,它是一个不可逆的时空过程.由于介质的粘性,外力功的一部分花在粘性耗散上,只有弹性应变能是地震发生及震后过程可利用的能量.我们将弹性应变能从总能量中分离出来,并就标准线性体给出了简洁公式.以海城地震为例,计算了两个共线不等长断层在地震孕育过程中其周围区域的应力场和能量场的时空变化图象及应变能积累曲线.结果表明,应变能分布复杂,在时间和空间上都很不均匀,能量积累在孕震初期较快而在后期渐趋平缓.由此讨论了某些地震前兆,认为当能量增加速率较大时某些早期前兆可能出现,比如唐山地震10年前出现的某些异常可能就是这种早期前兆表现.
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| 关 键 词： | 流变断裂 双断层 能量积累 地震孕育 |
ENERGY ACCUMULATION OF SEISMOGENIC PROCESS BEFORE SUBCRITICAL SPREADING IN RHEOLOGICAL MEDIUM |
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| TENG CHUN-KAI BAI WU-MING.ENERGY ACCUMULATION OF SEISMOGENIC PROCESS BEFORE SUBCRITICAL SPREADING IN RHEOLOGICAL MEDIUM[J].Chinese Journal of Geophysics,1991(1). |
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| Authors: | TENG CHUN-KAI BAI WU-MING |
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| Abstract: | Using rheological fracture mechanics method, we studied the seismogenic process in a rheological body. This problem is different from elastic one in that it is a irreversible process in time-space. Since the viscou dissipation, only part of work due to external force is available for earthquake occurence and post-easthquake process. By separating elastic one from the total energy a compact formula for standard linear body is derived and applied to the study of Hai-chen earthquake 1975. The variation patterns in time and space of stress, strain and strain energy as well as the curve of energy accumulation. The results show that the distribution of strain energy unsmoothly varies not only with space but also with time. The rate of strain energy accumulation at the initial stage of seismogenic process varies rapidly, but after that it becomes slowly down. We also discussed some seismic precursors and it appeals that some early seismic precursors may be energy when the rate of energy accumulation is high, for example, some precursors had appeared before 10 years of Tanshen earthquake of 1976. |
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| Keywords: | Rheological fracture Energy accumulation Subcritical spread Seismogenic process |
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