IGPP is pleased to invite you to join its Winter 2024 Seminar Series presentation featuring postdoc Bar Oryan. Dr. Oryan's talk, "Megathrust locking encoded in subduction landscapes" will occur at 3pm WEDNESDAY March 13, 2024.
Time: 3:00 pm, Pacific Time
Location: Revelle Conference Room
Abstract: Geodetic coupling models are a widely recognized tool for evaluating earthquake hazard, with highly coupled regions expected to slip in subsequent large earthquakes. However, recent studies challenge this view by indicating that locked megathrust regions could impede ruptures, while creeping faults may host earthquakes, challenging our current assessment of earthquake hazards. Unfortunately, traditional geodetic tools often cover only a fraction of the thousands of years over which seismic cycles span, and thus cannot fully shed light on this matter. In my talk I will present a new method I designed to extract long-term uplift patterns from landscapes, nicknamed ‘river geodesy’. This Bayesian inversion method capitalizes on the fact that topography reflects the interplay between uplift and erosion on 10 kyr+ timescales so rivers incising the landscape can be used to infer long-term uplift associated with cumulative, non-recoverable strain. I will continue and demonstrate how interseismic locking gradients induce increments of irreversible strain manifested predominantly as distributed seismicity across the overriding plate. Summing these increments over dozens of earthquake cycles produces a spatially-variable field of uplift representing the unbalance of co-, post-, and interseismic strain, highlighting the role geomorphology can play in constraining Earth's greatest source of seismic hazard.