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earthquakes. The study comprises five elements, each presented as a chapter of the report:
Survey of basic and applied earthquake science from ancient times to the present day, with a discussion of lessons drawn from past research
Evaluation of the current status of seismic hazard analysis and its connections to earthquake engineering, loss estimation, and risk mitigation
Examination of the new technologies in the main observational disciplines of seismology, geodesy, geology, and rock mechanics
Technical assessment of the key issues for future earthquake science, including the application of a dynamical systems approach to integrate observations
Analysis of research opportunities and requirements.
The study of earthquakes, like the science of many other complex natural systems, is still in its juvenile stages of exploration and discovery. Research has been focused on two primary problems: (1) earthquake complexity and how it arises from the brittle response of the lithosphere to deep-seated forces, and (2) the forecasting of earthquakes and their site-specific effects. Investigations of the first problem began with attempts to place earthquake occurrence in a global framework and contributed to the discovery of plate tectonics, while work on the second addressed the needs of earthquake engineering and led to the development of seismic hazard analysis. The historical separation between these two lines of inquiry has been narrowed by recent progress on dynamical models of earthquake occurrence and strong ground motion. This research has transformed the field from a haphazard collection of disciplinary activities into a more coordinated system-level science that seeks to describe seismic activity not just in terms of individual events, but as an evolutionary process involving dynamical interactions within networks of interconnected faults. The bright prospect for “earthquake system science” is a major theme of this report.
Experience shows that much can be learned from multidisciplinary investigations coordinated in the aftermath of large earthquakes, and it makes clear the importance of standardized instrumental data and geologic field work. During the last decade, research has been accelerated through the development of new observational and computational technologies. Subsurface imaging can now be applied with sufficient resolution to delineate the deep, three-dimensional architecture of fault systems. Neotectonic studies are improving constraints on fault geometries and long-term slip rates, and paleoseismology is furnishing an extended