KINEMATICS OF MODERN CONVERGENT MARGINS REVEALED BY SPACE GEODESY

Technology innovations within geodesy have supported steady advancement towards the goal of millimeter-level global geodesy. Modern space geodesy provides new observational capability for contemporary deformation and magmatism in active convergent margin systems that operate over a spectrum of temporal and spatial scales. Time scales vary from seconds to millennia, and spatial scales from borehole nanostrains to the global plate circuit. High-precision strain or three-dimensional point observations with borehole strainmeter or Global Positioning System (GPS) observations and geodetic imaging with SAR and LiDAR are used in combination to reveal these complex systems. GPS now combines with strong ground motion accelerometer time series to provide major enhancements to conventional seismology. The resulting three-dimensional fully georeferenced dynamic positioning time series are free of ambiguities associated with seismometer tilt and displacement. Geodesy constrains plate kinematics for convergence rate and direction, co-seismic deformation during great and moderate earthquakes, episodic tremor and slip events and related transient deformation, tectono-magmatic interactions, and the possible triggering effects of atmospheric or geomorphic unloading.

NSF’s National Earth Science Geodetic Facility – UNAVCO – supports a vibrant research community of investigators who interrogate convergent margin processes (among many other topics) using modern geodesy. This overview will sample a wide range of recent innovations from the UNAVCO community that reveal modern convergent margin deformation, and complement the lifetime contributions of Jason Saleeby and his collaborators to understanding the rock record of these dynamic systems.