| Summary: | One tool to help combat the increasing concentration of carbon dioxide in the atmosphere isgeological carbon sequestration (GCS), in which carbon dioxide is dissolved in water orpressurized to a supercritical fluid and injected below the surface. If the injection site containsminerals with divalent cations, the acidic fluid can liberate these atoms through mineral dissolutionand precipitate carbonate minerals, trapping carbon dioxide in the mineral structure. This processis already occurring at the CarbFix program in Iceland, where dissolved carbon dioxide in wateris being sequestered into basalt. The injection process and dissolution of minerals, however, mayweaken the rock, which can lead to induced seismicity. In the Earth’s crust, time dependent brittledeformation transpires when rocks are loaded to stresses below their peak strength for extendedperiods of time, a phenomenon that has recently become of interest to scientists as a possible preearthquake mechanism. Previous studies have shown that rocks can undergo sub-critical crackgrowth leading to a phenomenon known as brittle creep, which can be divided into three stages:(1) primary, decelerating creep; (2) secondary, constant creep; and (3) tertiary, accelerating creep.In this project, I deform samples of Etna Basalt at different effective pressures and with varyingpore fluids to determine the effect of carbon sequestration and reservoir conditions on brittle creep.Our results show that Etna Basalt strain rates do not significantly increase with additional loadinguntil the samples reach bulk dilation. This is in stark contrast to previous experiments conductedonly at high stresses, which show a high correlation between stress and strain rate, and work by onIceland Basalts, which show stress sensitive behavior even at low stresses. Additionally, thepresence of carbon dioxide in the pore fluid and changes in effective pressure did not lead tosignificant alterations in the strain rates. We propose that the stress-insensitivity may be due tosmall crack ...
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