The Challenges and Perils of Earthquake Prediction
Speaker: David Moecher
Date: Monday, April 8, 2013 at 6:30 p.m. Seating is limited. Reservations required.
Location: Davis Marksbury Building
Although the location and mechanism of most earthquakes are well known, predicting WHEN a major earthquake will occur with sufficient accuracy to prevent damage or loss of life is virtually impossible. We’ll consider why this is so difficult and examine the current technical limits of, and scientific disagreements about, earthquake prediction.
What’s the relevant science going on inside Earth? How are probability and statistics crucial to advancing our predictive capabilities? Why are the stakes increasing, to the degree that some seismologists go to prison? What’s the ongoing debate about Kentucky’s own New Madrid fault?
Review of Global Seismicity
Predicting earthquakes has been a goal of seismology for centuries. In spite of increasing understanding of how faults work and earthquakes are produced, predicting when a damaging earthquake will occur is still very challenging. The fundamental information for predicting earthquakes is the earthquake record of when and where earthquakes occur. This section summarizes the distribution of seismicity on earth.
Fault Behavior and Complexities
This section discusses the approaches for understanding faulting and generation of earthquakes. Understanding faulting and earthquake generation is basic first semester physics, in particular understanding forces and friction, elastic behavior of crust and propagation of waves through matter. Understanding earthquakes also requires geologic examination of ancient faults and fault rocks that are now exposed at Earth’s surface.
Basics of Prediction and Risk Assessment
Past earthquake prediction efforts were based on several basic tenets (“the earthquake paradigm”) that are now being questioned by some seismologists. Earthquakes exhibit simple statistical distributions that can be used to understand their recurrence. Basic probability can be used to estimate earthquake recurrence intervals. Seismic risk is defined.
What’s New with New Madrid?
Surprisingly, the New Madrid seismic zone is considered as high of a seismic risk than the San Andreas Fault zone in California. This section highlights the apparent inconsistency with present estimates of seismic risk in the U.S. and Japan. Estimates of earthquake recurrence intervals can also be obtained from paleoseismology: evidence of prehistoric earthquakes preserved in the rock and sediment record.