Geodesy, Seismicity, Neotectonics Shimon Wdowinski Rowena Lohman Cecilio Rebollar Gina Schmalzle Kim Outerbridge Jeff McGuire Gordon Seitz Pat Williams Tini Plattner Jose Frez

What do we know? First-order kinematics –major blocks, major faults, slip rates, major earthquakes, major active structures (on-land), uplift rates. Second order kinematics –Secondary faults, second order active structures. Current deformation processes –Earthquake deformation cycle, creep, delamination, folding.

What we do NOT know How does the lithosphere accommodate extension and transcurrent motion during the current stage of rifting? Details of the kinematics –Detailed EQ catalog –Paleoseismic earthquake catalog –Dense GPS network (current coverage is equivalent to that of Southern California in early 1990’s). –Dense SAR data coverage –Secondary faults (on-land & off-shore) Understanding the dynamics –Detailed 3-D map of crustal properties (composition, seismic velocities, thermal structure, strength, rheology) –Seismic efficiency (relative importance of seismic vs. aseismic slip) –3-D visco-elastic models

How much progress did we make on the science plan No. 6: To understand the distribution of the extension and transcurrent strain with depth, in map view, and in time. No. 3: To characterize the rift as a thermo-mechanical system (rheological flow laws, brittle failure, low-angle normal faults).

What progress did we make that is not on the science plan? Identified new deformation processes –Delamination –Triggering of earthquakes by aseismic creep –Compound focal mechanism in Delfin Basin