Abstract

Detailed seismic imaging and in situ stress and pore-pressure measurements are used to analyze reverse-fault reactivation of a long-dormant normal fault in the northern North Sea. Fault reactivation is caused by three factors: (1) a recent increase in the compressional stress in the area associated with postglacial rebound, (2) locally elevated pore pressure due to the presence of natural gas in a hydrocarbon reservoir on the footwall side of the fault, and (3) a fault orientation that is nearly optimally oriented for frictional slip in the present-day stress field. We demonstrate that the combination of these three factors induces fault slippage and gas leakage along sections of the previously sealing reservoir-bounding fault. We argue that similar pore-pressure triggering of fault slip in the crust may occur because of the accumulation of gas columns of, e.g., CO2 and He in the vicinity of tectonic faults.

You do not currently have access to this article.