Lamont Earth Science Colloquium presents:
Megathrusts and Splay Faults: Investigating the Source of the Next Great Cascadia Subduction Zone Earthquake and Tsunami
with Dr. Harold Tobin, Professor, University of Washington.
The giant subduction zone plate boundary fault off the coast of the Pacific Northwest has hosted magnitude 9 earthquakes and devastating tsunamis in the past and will inevitably do so again in the future. The main subduction fault – or megathrust – is "locked and loaded" beneath the offshore continental margin, accumulating the strain that will be released when it happens. The geometry of, and physical conditions within, that fault zone and its splay fault offshoots will determine the pattern and amount of seafloor uplift that creates the tsunami. Combining geophysical imaging at multiple scales of resolution with geologic insight informed by laboratory experiments provides insight into how that seismic event may unfold. Shifting the focus to the high mountains of Olympic National Park, a newly-discovered and very extensive outcrop of a major fault zone likely represents an exhumed paleo-megathrust, providing a direct window into the architecture of the Cascadia seismogenic system for the first time.
The Earth Science Colloquium Series, sponsored by Lamont-Doherty Earth Observatory and Columbia University Department of Earth and Environmental Sciences (DEES), provides a lively forum for discussing a wide variety of topics within the Earth sciences and related fields. Colloquia are attended by the full range of scientific and technical staff at LDEO. Colloquium attendance is required of all pre-orals DEES graduate students. The Colloquium Series supports the Lamont Seminar Diversity Initiative.
