The San Andreas fault at Parkfield, California, apparently late in an interval between repeating magnitude 6 earthquakes, is yielding to tectonic loading partly by seismic slip concentrated in a relatively sparse distribution of small clusters (<20-meter radius) of microearthquakes. Within these clusters, which account for 63% of the earthquakes in a 1987-92 study interval, virtually identical small earthquakes occurred with a regularity that can be described by the statistical model used previously in forecasting large characteristic earthquakes. Sympathetic occurrence of microearthquakes in nearby clusters was observed within a range of about 200 meters at communication speeds of 10 to 100 centimeters per second. The rate of earthquake occurrence, particularly at depth, increased significantly during the study period, but the fraction of earthquakes that were cluster members decreased.

6This paper gives an overview of the advances made in the field of risk assessment and risk management 7 of geologic CO 2 storage (GCS) since the publication of the IPCC Special Report on Carbon Capture and 8Storage in 2005. Development and operation of a wide range of demonstration projects coupled with 9 development of new regulations for safe injection and storage of CO2 has led to development and 10 deployment of a range of risk assessment approaches. New methods and tools have been developed for 11 quantitative and qualitative risk assessment. These methods have been integrated effectively with 12 monitoring and mitigation techniques and deployed in the field for small-scale field tests as well as 13 large-scale commercial projects. An important development has been improved definition of risks, 14 which can be broadly classed as site performance risks, long-term containment risks, public perception 15 risks and market risks. Considerable experience has now been gained on understanding and managing 16 site performance risks. Targeted research on containment risks and induced seismicity risks has led to 17 improved understanding of parameters and processes influencing these risks as well as identifying key 18 uncertainties that need to be targeted. Finally, significant progress has been made to effectively 19 integrate communication strategies with risk management approaches to increase stakeholder 20 confidence in effectiveness of deployed risk management approaches to manage risks. 21

No abstract

No abstract