van Manen, S.M.; Bromley, C.J. 2011 Induced seismicity in geothermal reservoirs : a literature review of triggering mechanisms, case studies and management strategies. Lower Hutt, N.Z.: GNS Science. GNS Science report 2011/21 27 p.
Abstract: This report presents a public-domain literature review of induced seismicity in geothermal reservoirs. Induced seismicity has been observed in relation to injection and withdrawal of fluids in conventional geothermal systems. The exact mechanisms remain unclear. In enhanced geothermal systems, microseismicity is predominantly due to hydraulic fracturing during high pressure stimulation and fluid circulation. A total of 14 case studies of induced seismicity in conventional and enhanced geothermal systems worldwide, including New Zealand, are presented. These illustrate the range of activities and geological settings in which induced seismicity occurs. The mechanisms that trigger induced seismicity remain unclear at this point in time being the subject of some conjecture. The main issue concerning induced seismicity is not the damage (or lack thereof) it causes, but rather the public’s perception of this phenomenon. Recent work by the IEA-GIA has involved developing ‘best practice’ protocols, but proven methodologies are still lacking. An important part of any geothermal development should be outreach and communication with the local community, as maintaining public trust fosters confidence, investment, easier land access and project approval. Therefore it is recommended that a quantitative approach to risk assessment, mitigation and management should be implemented, in conjunction with appropriate outreach programmes, prior to the start of new geothermal developments. (auth)