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arXiv 2202.11642physics.geo-ph
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2008年汶川大地震记录到的强波形的性质和能源

Nature and Energy Source of the Strong Waveforms Recorded during the 2008 Wenchuan Earthquake

Xiaoping Mao, Xueqiang Zhang, Yuci Su, Ke Mao, Pengyu Lu, Fei Zhang

摘要:

地震确实是由断层错位引发的,但这一过程本身是否能产生主震释放的实际地震能量,长期以来一直受到质疑。因此,探索第一次运动后引起地震的真正能量来源是必要的。通过对震中附近地震台的波形和射线路径的分析,认为强烈的地震振动可能不是由S波引起的。并提出沉积地层中的储层中含有大量的高压流体,其压力在一定条件下可以释放,这种压力释放可能是主地震能量的重要组成部分。当天然断层破裂并穿透大面积的水库时,压力释放产生的弹性能量可达到8.0级地震释放的能量。人为工程活动会导致小规模的流体压力释放现象,如钻井过程中的井喷和水力压裂引起的地震。许多直接和间接的证据,如汶川地震时记录的地震波的时域和频域特征,地面观测到的爆炸现象和科学钻探获得的岩心,都表明这种能量释放的可能性。我们认为,地震活动可分为三个阶段:微破裂阶段,在此阶段有流体活动并能产生动电效应;初始运动后的显著破裂阶段;流体压力释放引起的强震阶段。

英文摘要:

Earthquakes are indeed triggered by fault dislocations, but whether this process alone can produce the actual earthquake energy released by the mainshock has long been questioned. Therefore, exploring the true source of energy that causes earthquakes after the first motion is necessary. Based on analyses of the waveforms and ray paths at seismic stations close to the epicenter, it is considered that strong earthquake vibrations may not be caused by S-waves. It is also proposed that the reservoirs in sedimentary strata contain large amounts of high-pressure fluids, whose pressures can be released under certain conditions; this release of pressure may be an important component of the main earthquake energy. When a natural fault ruptures and penetrates a reservoir with a large area, the elastic energy produced by the release of pressure can reach the energy released by an earthquake of magnitude 8.0. Artificial engineering activities can lead to small-scale fluid pressure release phenomena, such as blowouts during drilling and earthquakes induced by hydraulic fracturing. Much direct and indirect evidence, such as the characteristics of seismic waves in the time and frequency domains recorded during the Wenchuan earthquake, explosion phenomena observed on the ground and cores obtained by scientific drilling, indicates the possibility of such energy release. We propose that seismicity can be divided into three stages: the microfracturing stage, in which there is fluid activity and can produce an electrokinetic effect; the significant fracturing stage after the initial movement; and the strong earthquake stage caused by fluid pressure release.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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