Distinguished Lecture Series: Dr. Thomas H. Jordan
The Prediction Problems of Earthquake System Science
System science seeks to explain phenomena that emerge from nature at the system scale, such as global climate change or earthquake activity in California or Alaska. The 'system' is not a physical reality, but a hypothetical representation of nature, typically a numerical model or ensemble of models that replicates an emergent behavior and predicts its future course. In this presentation, Professor Jordan will describe how system-level models of fault rupture and seismic wave propagation are improving our understanding of earthquake predictability by posing interesting problems of contingent predictability as physics questions in a system-specific context. As an example, he will show how more accurate earthquake simulations using realistic three-dimensional crustal models can reduce the aleatory variance of the strong-motion predictions by a factor of two relative to the empirical ground motion prediction equations in current use, which would lower exceedance probabilities at high hazard levels by an order of magnitude. He will also discuss the new capabilities for operational earthquake forecasting that are being developed in several countries, including the Italy, New Zealand, and the United States.