Earthquakes may disrupt potential carbon storage reservoirs and thus need special attention. Accordingly, this study evaluates the natural seismic activity which may disturb the long-term and large-scale CO2 storage potential of several saline aquifers in southern Israel. This work is part of the characterization of the proposed sequestration sites in Israel and is based on all the existing seismological and earthquake related data. First all the historical and modern earthquake catalogs were gathered and the pattern of seismicity in space and time in relation with the study area was examined. Our perspective is then extended beyond the limited term exhibited by these records, and resorted to all the available neotectonics elements, namely geomorphic features, stress field indicators and geodetic measurements. Based on the seismotectonics of the research area, the areas relevant to CO2 storage is constrained in accordance with the following leading criteria: (1) farther than 10 km away from any Md > 3 seismic event, and (2) at least 10 km away from potential surface rupture (active faults in terms of the Israeli building code) and other major fault zones. These were integrated with the additional criteria of: (1) more than 800 m depth to the top of the aquifer, and (2) more than 100 m thickness of the capping sealing aquitard, that were determined previously (Calvo and Gvirtzman, 2013, IJGGC 14: 25-38). Overall, the area relevant for CO2 storage in Israel is reduced to about 4250 km(2). Three proposed storage sites were examined and found to be located well within the reduced area of interest (AOI), at least 36 km away from the nearest recorded Md > 3.0 earthquake. These outcomes are presented on a summary map, an effective way to explain this process and outcomes to the decision makers. Henceforth, there is the need to set threshold criteria that will guide the collecting of the missing data, fill the knowledge gaps and direct future investigations. Such are, for example, the accurate monitoring of natural weak seismicity and the state of stress within the proposed sites. Hazards that cannot be measured directly will need modeling and sensitivity analysis such as the potential role of the present day stress field and induced seismicity, whether they are capable of damaging the integrity of the potential aquitard. These actions will allow determining whether the proposed sites do meet with the necessary requirements and predicting the behavior of the reservoir rocks under different conditions until failure and escape of the sequestrated material. (C) 2016 Elsevier Ltd. All rights reserved.
