Continental Deformation in Asia from a Combined GPS Solution
Calais, E., L. Dong, M. Wang, Z. Shen, and M. Vergnolle, Continental
deformation in Asia from a combined GPS solution,
Geophys. Res. Lett., 33, L24319, doi:10.1029/ 2006GL028433, 2006.
After decades of research on continental tectonics, there is still no
consensus on the mode of deformation of continents or on the forces that
drive their deformation. In Asia the debate opposes edge-driven block
models, requiring a strong lithosphere with strain localized on faults,
to buoyancy-driven continuous models, requiring a viscous lithosphere
with pervasive strain. Discriminating between
these models requires continent-wide estimates of lithospheric strain
rates. Previous efforts have relied on the resampling of heterogeneous
geodetic and Quaternary faulting data sets using interpolation techniques.
We present a new velocity field based on the rigorous combination
of geodetic solutions with relatively homogeneous station spacing,
avoiding technique-dependend biases inherent to interpolation methods.
We find (1) unresolvable strain rates (less than 3x10^9/yr) over a
large part of Asia, with current motions well-described by block or
microplate rotations, and (2) internal strain, possibly continuous,
limited to high-elevation areas.
Horizontal GPS velocities shown with respect to Eurasia. Large
velocities at sites on adjacent plates are shown transparent for a
sake of readability.
Second invariant of the stain rate tensor calculated
for a Delaunay triangulation.