Investigation of induced seismicity and aseismic deformation in response to CO2 injection and related pressure changes

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In recent years of global warming, the reduction of CO2 emissions e.g. by employing carbon capture and storage (CCS) became increasingly important. To reduce the current speed of global warming, a tremendous amount of CO2 would need to be injected within geological subsurface storages. The main threat to the integrity of CO2 storages is that even small- to moderate-sized earthquakes triggered by injection of these large volumes may break its seal. Since 2007, CCS research has been carried out by the CO2 Lab of the University Centre in Svalbard (UNIS). So far, several injection tests have been conducted and a high-frequency geophone network surrounding the injection well has been established to detect microseismic events. Whereas the first fluid injection in 2010 was associated with high-frequency earthquakes, later injection tests did not generate any detectable events. Nevertheless, pressure and flow rate showed a pattern characteristic for fracture opening potentially indicating aseismic fracture propa gation or slow slip. We will focus on the following problems: - What is the value of microseismic monitoring: do event locations form a good representation of the main flow directions? Does microseismic activity allow for conclusions on rock properties or only helps to identify regions of high pore pressure? - Is there aseismic deformation during fluid injection at the CO2 Lab? How can we quantify its amount? What can these observations contribute to the understanding of the injective/hydraulic behaviou r of the rock? - Can we make use of the continuity of seismic recordings by analysing the noise in addition to the signal? Can we employ ambient seismic noise tomography to enhance our understanding of fluid flow and changes in the subsurface qualitativel y as well as quantitatively? - Is it feasible to turn Svalbard into a CO2 neutral community by injecting a sufficient amount of CO2 in subsurface reservoir(s) without breaching the caprock?