Significance of Stress Transfer in Time-Dependent Earthquake Probability Calculations

Journal of Geophysical Research, Vol. 110, B05S02 — 2005

Tom Parsons of the U.S. Geological Survey, Menlo Park, CA, investigated a central question in earthquake science: does the interaction between earthquakes on nearby faults advance or delay future events? This 2005 paper presents a method for calculating earthquake probabilities that accounts for stress transfer — the way one earthquake changes the stress state on surrounding faults.

Approach

If earthquakes struck a given fault on a perfectly regular schedule, forecasting would be straightforward. In reality, earthquake recurrence is irregular. Parsons used long-term records of past earthquake activity and incorporated the effects of stress transfer between faults to refine probability estimates over specified time windows.

Key Findings

The research examines whether stress changes caused by one earthquake can measurably advance or delay the timing of subsequent events on nearby faults. By combining historical seismicity catalogs with physics-based models of fault interaction, the study provides a framework for more realistic time-dependent hazard assessment.

This work contributes to the broader goals of the Tokyo Project, which evaluates earthquake threat to the greater Tokyo metropolitan region.