Induced seismicity in the Gazly gas field region

On the territory of the Bukhara-Khiva gas and oil-bearing area of western Uzbekistan which belongs to the 7°-seismic zone severe earthquakes have occurred in the region of the large Gazly gas field on April 8, 1976 ( M = 7), on May 17, 1976 ( M = 7.3) and on March 20, 1984 ( M = 7.2). The problem of a possible effect of the gas field exploitation on the total course of seismicity and of the genesis of the severe earthquakes has been studied. Methods of qualitative and quantitative analysis employing an adaptive statistical method were used. A system of parameters which describe the manifestation of the gas field was set. A statistical model of induced seismicity for the gas field was obtained. The threshold values of the trigger parameters which ensure optimum operating conditions of the gas field and seismic stability in the region were set. A forecast of a possible severe earthquake in 1993 – 1994 in western Uzbekistan is made.