Fracturing, fault-induced

Caving face after fully mining of initial pressure, pressure and other process cycles, the overburden rock elliptic band will disappear, mining-induced fracture belt on both sides of the fault zone will be formed Fracture zone of level distribution is still the approximate ellipse area, called the circle of mining fissure elliptic. 

In certain situations, FE could prove useful in the remote detection of fracture. An unusual radio emission observed at several widely space receivers six days before the Great Chilean Earthquake of May 22,1960, has led Warwick, Stoker, and Meyer to speculate that stress induced microfracture along the Chilean fault was the source of this emission (38). More recent observations of RE some hours to tens of minutes before earthquakes have been made by Soviet researchers (39). Nitsan has surveyed a number of minerals for fracture related RE and has concluded that quartz-bearing rocks were sources of rather intense RE (IS). Under similar conditions, rocks not containing quartz (basalts, obsidians, limestones) did not yield detectable RE. Therefore, RE is expected to be a strong function of the mineral content (quart or non-quartz bearing formations). Formation structure (the presence of previously pulverized material, state of stress and strain) is also expect to affect RE intensity. 

As illustrated in Fig. 14b, pressure-inhibited charge is less likely in cases where hydrocarbons are able to migrate across the boundary of different pressure cells. In these cases the concept of pressure equilibrium does not apply as reservoir pore pressure is unrelated to the migration of hydrocarbons from the overlying seal. Excess reservoir overpressure relative to the seal may therefore induce hydraulic fractures which breach both the seal and the overburden. It follows that closures located near to frequently reactivated boundary faults have a relatively greater... 

The physical defects have existed widely in the natural rock, such as fracture, joint and fault and other discontinuous structural plane. The physical and mechanical characteristics of the rock have been influenced seriously by the structural plane, and also the seepage and thermodynamic features and other characteristics have been determined mostly according to the structural plane. It involves mine excavation, environment protection, water conservancy construction, radioactive waste disposal and reservoir induced geologic hazard etc. 

Earth s crust, (b) dike intrusion propagation (for more details see section Earthquake Swarms Induced by Magmatic and Volcanic Activity ), or by (c) pressurized hydrothermal fluids diffusing within permeable fracture zone alraig the fault. Accordingly, Vidale and Shearer (2006) suggest that the fluid pressure fluctuations or aseismic slip as plausible driving mechanisms of the swarm-Uke sequences in southern California (section Occurrence of Earthquake Swarms in the World ). 

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