The potential value of induced microearthquake (microseismic) imaging for the monitoring and management of fractured hydrocarbon reservoirs is illustrated using a high quality data set obtained during development of the European Hot Dry Rock (HDR) geothermal energy project, Soultz-sous Forets, Alsace, France. This development has involved massive hydraulic fracturing Operations (MHF), waterfloods and water extraction in a naturally fractured rock mass. The characteristics of the development, operation and hydraulic behaviour of this system are in many ways analogous to those of fracture dominated hydrocarbon reservoirs. The data set consists of 28,000 located microseismic events detected during two phases of reservoir development, comprising a total injected fluid volume of 1 50,000m3. The microseismic data has provided detailed images of the 500Mm3 reservoir volume, successfully identifying the hydro-mechanical controls on fracture dominated flow an isotropy, enabling the successful targeting of a production well and allowing delineation of the principal flow paths. The analysis of microseismic connectivity has recently been used to successfully construct a reservoir simulator grid for modelling the long term performance of the reservoir.