Cryptoexplosive breccia: A genetic mark of the paleoearthquakes

Abstract

全球到处发育的隐爆角砾岩表明隐爆作用的普遍性，并标志着古地震的一种形成机制。隐爆角砾岩具有特殊的角砾形状和构造。地震地质资料表明大地震产生的地表破裂带没有肉眼可观测到的断层位移。材料聚集应变能估算值表明岩石聚集的应变能不足以产生大地震。携带高能量的地核-地幔流体不仅为自己逸散提供了能量，而且为产生地震提供了充足的能量。深部流体以运移-聚集-爆炸-运移-聚集-爆炸的循环方式向地表逃逸，在地球内部不同深度产生了不同震级的地震。因此，超高压流体隐爆应该是地震形成的主要机制。地震隐爆成因机制不仅能够更好地解释各种天然地震（中深源地震、震群、慢地震和非双力偶性地震等）以及全球地震、火山和地热带的空间吻合，而且能够解释隐爆角砾岩及其伴生矿的形成。;The cryptoexplosive breccias found all over the world indicated that cryptoexplosion was pervasive in the geological history. Cryptoexplosive breccias are characterized by the special structure, which indicates a genetic mark of paleoearthquakes. The seismic-geological data indicated that the great earthquakes produced the ruptures with evident surface displacement, but on visible fault displacement. Estimation of strain energy accumulated in the materials demonstrates that rocks in the crust and mantle cannot accumulate huge strain energy to produce great earthquake. High energy density fluids derived from the core and mantle can provide energy for their migration, as well as enough energy for producing great earthquakes. The deep fluids migrate upward in the way of migration-accumulation-explosion-migration-accumulation-explosion, producing earthquakes with the different magnitudes at different depths. Therefore, the crypto-explosion can be considered as the predominant mechanism of earthquake generation. The proposed genetic mechanism not only can be used to much better explain the generation of different kinds of earthquakes, such as the moderate and deep focus earthquakes, earthquake swarm, slow earthquakes and no-dipole-couple earthquakes, as well as special overlap of the seismic, volcanic and geothermal zones in the world, but also to explain the formation of ore deposits companied with cryptoexplosive breccias.