School of Geosciences Seminar Series - Cynthia Ebinger (Tulane University)

Dear All,

The seminar this week will be given by Prof. Cynthia Ebinger - Tulane University

Friday, March 22nd; HH108 at 1:30 pm

Cynthia will discuss about her work in Africa:

Active deformation occurs across broad areas of Africa, including > 150 km-thick, strong Archaean cratons, and oceanic lithosphere.  We compare and contrast earthquake patterns from two separate arrays, including the Rukwa rift where Africa’s largest earthquake recorded earthquake (M7.4) occurred. The precise relocations of earthquakes using a new regional velocity model, new local magnitude scale, and source mechanisms of local and teleseismic earthquakes are used to determine seismogenic layer thickness, delineate active faults, evaluate regional extension direction, and the geometry and kinematics of border faults.  Seismogenic layer spans the entire crust beneath the rift basins and their uplifted flanks (0-42 km), and the upper mantle in some areas.  Earthquakes at depths of 20-54 km and with steep nodal planes occur along subsurface projections of Tanganyika and Rukwa border faults, indicating that large offset (≥ 5 km) border faults penetrate to the base of the crust, and are the current locus of strain.  Our results indicate that steep, deep border faults remain active over at least 12 My of basin evolution. The low b-value indicates strong coupling across the faults, and the strain deficit from comparison seismic and geodetic strain are similar to patterns along some subduction zones, and suggest that earthquakes > M7.5 are missing from the historic record.  The strain deficit is even larger in magmatic sectors, where significant extension is accommodated by magma intrusion. Patterns indicate that mechanical strength and magmatism are the primary factors controlling rift architecture in cratonic rifts.

BIO

Professional Preparation

Duke University, Durham, NC BS, Marine Geology

MIT/WHOI Joint Program in Oceanography PhD, Marine Geology & Geophysics

Appointments

2017- : Marshall-Heape Chair, Tulane University

2006-16: Professor, University of Rochester

2004-06: Professor, Royal Holloway, University of London

1991-98: Lecturer, University of Leeds

1990-91: NATO Postdoctoral Fellow, Leeds University

1988-90: National Academy of Sciences Associate, NASA Goddard Space Flight Center

Synergistic Activities

Editor-in-Chief, Basin Research
National Research Council Committee for Seismology and Geodynamics
President-Elect, AGU College of Fellows Steering Committee