Induced Seismicity--A Challenge for Geothermal Project Development in Germany

Abstract

During the last years, exploitation of hydro-geothermal energy has attracted increasing attention in Germany. In several cases, felt earthquake activity occurred in the vicinity of geothermal sites after the systems went into operation. Although the observed earthquakes exhibited small magnitudes only, some of them were felt by the local population. No significant material damage was reported, however major concerns exist in the public regarding the safety of geothermal power production. The public perception of the seismic risk as well as the lack of regulative standards impedes the development of geothermal projects in Germany. Several hydrothermal projects are currently put on hold due to seismic risk concerns, and a quantitative assessment of the seismic risk has become mandatory. The basis for a seismic risk analysis is a detailed understanding of the physical processes associated with induced seismicity. This allows numerical simulations of reservoir operations and their impact on seismic risk. In combination with reaction plans (traffic light system), where hydraulic operations are modified or even stopped when induced earthquakes become to strong, the seismic risk can be controlled and minimized.