Full-Waveform based methods for Microseismic Monitoring Operations an Application to Natural and Induced Seismicity in the Hengill Geothermal Area, Iceland

摘要

Abstract. Geothermal systems in the Hengill volcanic area, SWIceland, started to be exploited for electrical power and heat productionsince the late 1960s. Today the two largest operating geothermal powerplants are located at Nesjavellir and Hellisheiei. This area is acomplex tectonic and geothermal site, located at the triple junction betweenthe Reykjanes Peninsula (RP), the Western Volcanic Zone (WVZ), and the SouthIceland Seismic Zone (SISZ). The region is seismically highly active withseveral thousand earthquakes located yearly. The origin of such earthquakesmay be either natural or anthropogenic. The analysis of microseismicity canprovide useful information on natural active processes in tectonic,geothermal and volcanic environments as well as on physical mechanismsgoverning induced events. Here, we investigate the microseismicity occurringin Hengill area, using a very dense broadband seismic monitoring networkdeployed in Hellisheiei since November 2018, and apply sophisticatedfull-waveform based method for detection and location. Improved locationsand first characterization indicate that it is possible to identifydifferent types of microseismic clusters, which are associated with eitherproduction/injection or the tectonic setting of the geothermal area.