Taiwan is located on the Circum-Pacific Seismic Zone, and disturbed by the countless earthquakes every day due to the convergence and collision between the Eurasian plate (EP) and the Philippine Sea plate (PSP). The PSP is in the southeastern of Taiwan, keep moving to the northwestern direction toward the EP at a velocity of 82 mm/year. The EP subducts under the PSP in the Huatung valley, the southeastern of Taiwan, and extends southern to the Manila trench. The collision between the two plates make the Taiwan island keep rising and growing taller, and this geological movement is named orogeny. There exists two different orogenic theories in Taiwan. One theory, which is called thin-skinned model, states that only the upper crust is compressed and deformed, and there is no business with the EP below the PSP. Another one is called the thick-skinned model, asserting that both the EP and PSP take parts in the orogeny and are deformed by the collision. Ever since, there has been a debate about the two theories. There are some evidences that can support each theory respectively, but it’s still lack of decisive witness. A team composed of the Department of Geoscience and the Institute of Oceanography at National Taiwan University (NTU) and the Institute of Earth Sciences at Academia Sinica published a paper in Science journal this August, and solved this permanently mystery successfully using a new technology and observational data. This paper utilized the ambient seismic noises from broadband stations, and a high resolution three-dimensional model of seismic anisotropy of Taiwan was built using the noise-derived empirical Green’s functions. From these images, they found that the deformation happened in both upper and lower plates, and it seemed more similar with the traditional thick-skinned theory. However, the results also reveal that the deforming mechanism are totally different in the upper and lower crust, and it seemed to be the layered phenomenon described by the thin-skinned model. Thus, the two traditional theories cannot well explained those messages. The research provided a brand-new orogenic model of Taiwan. The upper crust is dominated by collision-related compressional deformation, whereas the lower crust by convergence-parallel shear deformation. They interpret this lower crustal shearing as driven by the continuous sinking of the Eurasian mantle lithosphere when the surface of the subducted plate is coupled with the orogen. This paper found out the mystery of the geological research in Taiwan. Both the upper and lower crusts participate the orogeny, but their deformation mechanisms are totally different. The proposed coupled layered deformation mechanism in this research provides an alternative view of mountain building and clearly defines the role of subduction in the formation of the Taiwan mountain belt. Figure caption Cartoon illustration of the coupled layered deformation zones in the Taiwan orogen. The compressional tectonics and the subduction-dominated deformation are characterized by the orogen-parallel anisotropy and the convergence-parallel anisotropy, respectively. Red double arrows highlight the fast directions of these two sets of anisotropy. The anisotropy transition boundary (green dots) separates the two deformation regimes and couples the upper crust of the orogen with the subduction. Reference Tzu-Ying Huang, Yuancheng Gung, Ban-Yuan Kuo, Ling-Yun Chiao, Ying-Nien Chen (2015) Layered deformation in the Taiwan orogeny, Science, 349(6249), 720-723. 33. DOI: 10.1126/science.aab1879. The paper http://www.sciencemag.org/ content/349/6249/720.abstract and the perspective http://www.sciencemag.org/ content/349/6249/687 Associate Professor Yuancheng Gung Department of Geosciences ycgung@ntu.edu.tw