Dr. Ya-Ju Hsu, a Research Fellow at Institute of Earth Sciences (IES), Academia Sinica, and her research assistant Chi-Hsien Tang recently joined a collaborative work with the scientists from the Earth Observatory of Singapore (EOS). Their research has been published in Science on April 14, 2017.
　　In this research, large stress perturbation incurred by the 2016 earthquake sequence in Kumamoto, Japan, was used for image localization and distributed deformation. IES group estimates surface velocity change after the mainshock using continuous GPS data and constructs a preliminary model to invert for spatio-temporal distribution of strain rate in the lower crust. The strain rate and stress evolution is then used to investigate rheological properties in the lithosphere. Results show regions of low effective viscosity in the lower crust beneath the Mount Aso and Mount Kuju volcanoes were surrounded by larger-scale variations of viscosity across the back-arc. This study demonstrates a new potential for geodesy to directly probe rock rheology in situ across many spatial and temporal scales, which can be helpful in understanding the deformation of mantle and crustal rocks in response to stress and the distribution of seismic and volcanic hazards.
　　Full text of the paper is available at the Science website: http://science.sciencemag.org/content/356/6334/163