Faults reactivation

Donnelly, L.J. 2006. A review of coal mining induced fault reactivation in Great Britain. Quarterly Journal Engineering Geology and Hydrogeology, 39, 5-50. 

A common observation concerning oil inclusion abundance is that paleo-oil columns are common not only below current oil columns, but also in wells that are completely dry at present. For example, in the Timor Sea region of northern Australia, there was an extensive period of fault-seal breach of oil reservoirs during Late Miocene/Early Pliocene fault reactivation, and this left many paleo-oil columns in the presently water-filled reservoir sections [28,128]. In dry wells, the analysis of fluid inclusion oils offers the possibility of understanding a petroleum system without having access to current fluids in the reservoir [49,55,129], and potentially then being able to predict where the oil may have leaked to, or where it may be trapped in nonbreached structures. 

For the Xinli gold mine, the most probable inrush model is the big inflow of seawater into pits through FI and F2 (Yin et al. 2007 Wang Cao 2007). The past work of water inrush through fault paid much attention to fault spatial position, aquosity and breakage. The effect of fault reactivation on hydrogeological structure needs further exploration. 

In the Xinli gold mine mode, much attention need to be paid to fault reactivation, surface subsidence and fault effects on rock mass movement. 

The comparison of the two results can present the dynamic process of rock mass movement and deformation when mining proceeding. Fault reactivate, surface subsidence and stress concentration... 

Characteristics and mechanisms of mining-induced fault reactivations in an open-pit mine... 

Fault reactivation can directly cause damage to surface structures, services and utilities, and transport networks that located on or immediately adjacent to the fault. Many engineering disasters, such as slope instability, tunnel collapse, shaft damage, water inrush, and gas burst, are often closely associated with fault reactivations (e.g., Koukis et al. 2009 Suorineni et al. 1999 Wu et al. 2004 Karacan et al. 2008). 

Based on field observations and analysis of an open-pit mine, the kinematic behaviors of fault reactivations induced by slope excavation were identified and studied in this paper. The results will be helpful to the stability assessment, disaster prevention, and trend forecast of excavated slopes. 

TYPICAL FAULT REACTIVATIONS AND MECHANISMS CAUSED BY SLOPE EXCAVATION... 

In the mining area, when a steep fault outcropped at the tensional section of the excavated slope, namely, the upper segment of the excavated slope, the fault reactivation usually results in a downward movement on the hanging wall relative to the foot-wall. In this case, a single fault reactivation produces a fault scarp, whereas a group of parallel... 

Figure 2. Fault reactivation caused by excavation in the hanging wall of the fault.

When an antithetic fault is located in the lower segment of an excavated slope, the fault reactivation results in a normal fault-style movement and in back-facing scarps on the slope surface (Fig. 5). The relative movement between the two sides of the fault is mainly caused by the intense compression of the hanging wall slope rock mass. When the shear stresses on the fault plane exceed the shearing strength of the fault surface, the hanging wall slope slips along the fault plane. 

Figure 6. Checkerboard-patterned fault reactivation caused by slope excavation. 

In three-dimensions, the characteristics of fault reactivation are far more complicated than those in the plane strain conditions. Fault strike and the... 

And in lots of other situations, the checkerboard-patterned fault reactivation is primarily attributed to the changes in the location of the excavation center relative to the two fault groups. 

Figure 11. Checkerboard-patterned fault reactivation caused by two groups of faults intersect within the excavation area at a high angle.

As a response to excavation, the expression of fault reactivation is particularly evident when the trend of fault is parallel to the slope strike. In addition, on the periphery of the excavation area, the largest fault that has the steepest dip angle and the shortest distance to the slope usually presents the largest slip deformation and is first to be reactivated. 

The fault strike and the distance from the fault to the excavated slope significantly influence the expression characteristics of fault reactivation. The closer... 

Donnelly L. 2009. A review of international cases of fault reactivation during mining subsidence and fluid abstraction. Q J Eng Geol and Hydroge. 42 (l) 73-94. 

Tao ZY, Zhang LM. 1991. Study of factors relative to the fault reactivation. In proceedings of the international symposium on rock joints, Loen, 4-6 June 1990. A.A. Balkema, pp 487-493. 

Zhao Haijim, Ma Fengshan, Xu Jiamo, GuoJie. 2013. Preliminary quantitative study of fault reactivation induced by open-pit mining. Int J Rock Mech Min Sci. 59 120 127. 

Wiens DA, Snider NO (2001) Repeating deep earthquakes evidence for fault reactivation at great depth. Science 293 1463-1466... 

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