Reservoir induced seismicity studies related to the Wivenhoe Dam in southeastern Queensland - pre-pounding stage

The procedure is to observe the seismicity in the vicinity of a reservoir and so deduce the abundance of induced earthquakes for comparison with the background (or normal) seismicity of the region. This involves monitoring during the pre- and post-impounding stages, taking particular note of the rate of change of water level during filling and subsequent normal operations of the reservoir. Many such surveillance projects have been instigated and in the majority of cases, the results clearly indicate the existence of induced seismicity (Simpson, 1976). Subsequent studies then attempt to define causal relationships between the seismicity and parameters relevant to the reservoir, with particular emphasis on the effect of the regional ambient stress conditions (Gupta and Rastogi, 1976).The field procedures for reservoir induced seismicity studies are essentially those employed in standard microearthquake surveys and follow the recommendations given by Adams, Gough and Muirhead (1973).