摘要
介绍了含裂隙介质的APE理论 (anisotropicporo elasticity) .根据APE理论 ,对裂隙膨胀提出了新的看法 ,认为当岩石不产生大量破裂时 ,裂隙的扩张和闭合是互为依存、彼此平衡的 .用笔者建立的裂隙方向性集中体积模型的各向异性电导率张量表达式 ,研究了应力场导致裂隙纵横比变化与地壳岩石电阻率变化的关系 .结果表明 ,即使地壳岩石的平均体应变很小或不产生新的裂隙 ,也可以出现电阻率大的突变 .电阻率的正负变化及其量值都与裂隙纵横比及分布的方向有关 .这一结果适用于对离震源区较远的场兆的解释 。
The latest development of APE theory for anisotropy study is introduced and applied in electric problems. In the view of APE cracks modeling , it is believed that when there is no newly developed cracks, the dilatancy and closing of cracks balance each other. Using a new electric conductivity anisotropic model(named cubic model), put forward by present authors,for the cracked rocks containing fluid, the mechanism of earth resistivity precursor of earthquake is discussed according to the APE theory, considering the variation of aspect ratio to be the main source of the precursor due to stress change. It is concluded that the increasing or decreasing variation of earth resistivity with large amplitude before strong earthquakes could be explained easily by the new electric anisotropic model, even if the total porosity or strain do not change or there are no new cracks developed.Moreover, it is found that resistivity variation characteristics are related to the aspect ratio and distribution of cracks. But the conclusions from the discussion in this paper are effective only for seismic field precursor, not for source precursor related to new developed cracks.
出处
《西北地震学报》
CSCD
2000年第3期209-216,2223,共9页
Northwestern Seismological Journal
基金
地震科学联合基金资助项目!(198115)
