Lower-crustal rheology and thermal gradient in the Taiwan orogenic belt illuminated by the 1999 Chi-Chi earthquake.

ABSTRACT: The strength of the lithosphere controls tectonic evolution and seismic cycles, but how rocks deform under stress in their natural settings is usually unclear. We constrain the rheological properties beneath the Taiwan orogenic belt using the stress perturbation following the 1999 Chi-Chi earthquake and fourteen-year postseismic geodetic observations. The evolution of stress and strain rate in the lower crust is best explained by a power-law Burgers rheology with rapid increases in effective viscosities from ~10¹⁷ to ~10¹⁹ Pa s within a year. The short-term modulation of the lower-crustal strength during the seismic cycle may alter the energy budget of mountain building. Incorporating the laboratory data and associated uncertainties, inferred thermal gradients suggest

SUBMITTER: Tang CH 

PROVIDER: S-EPMC6392777 | biostudies-literature | 2019 Feb

REPOSITORIES: biostudies-literature