Reaction of the Underground Water to Seismic Impact from Industrial Explosions

A comprehensive monitoring at the territory of the Korobkovskoe and Lebedinskoe iron ore deposits of the Kursk Magnetic Anomaly (KMA), which are developed using explosive technologies, has been carried out since July 2019 near the town of Gubkin (Belgorod Region, Russia). A unique database of the responses of the system "reservoir-well" to short-delay explosions in a mine and a quarry has been formed with a sampling rate of 200 Hz on the basis of synchronous seismic, barometric, and precision hydrogeological measurements. The research object is groundwater in the zones of exogenous weathering and tectonic fracturing of the ore-crystalline basement of the Archean-Proterozoic. Processing hydrogeological responses to mass explosions in the mine and the quarry made it possible to indicate two types of water level response to seismic impact. In addition to coseismic variations in the pore pressure in the system "reservoir-well" for the first time postseismic hydrogeological effects were established during the exploitation of the iron ore deposits. The observed effects may have been caused by two mechanisms. The first mechanism is represented by the skin effect-a change in the permeability of a fluid-saturated reservoir in the near-wellbore space. The second one is the renewal of existing fracture systems and the formation of technogenic fractures in the zones of lithological-stratigraphic contacts and faults at the interface between weathered and relatively monolithic rocks. The subsequent decrease of the water level in the well is associated with the filling of the fractured zones with water.