| dc.description.abstract | Taiwan is located on the converging boundary of Eurasian and Philippine Sea plates, it is one of the most rapidly uplifting orogeny in the world. In this area, the pattern of the plate collision is occurred between two subducting systems, the geological structure here is quite complicate. So there are many models of the tectonic collision, from the typical thin-skinned thrust to the lithospheric collision, or some other models as uplifting of buoyancy. In this study, we attempt to describe the Moho depth beneath Taiwan by using amount of data from the project of Taiwan Integrated Geodynamic Reseach(TAIGER), and expect for the results can make some improvements to the construction of tectonic collision patterns of Taiwan orgoeny.
The land-explosion of TAIGER project was carried out from Feb to March on 2008, and it includes：1) 3 W-E line linear seismic arrays which were consisted of 800 Texans with spacing in 200 meters at northern, middle and southern Taiwan; 2) 2 N-S linear seismic arrays which were consisted of seismometers with spacing in 6 kilometers at middle and eastern Taiwan; 3) 10 explosion sources with the dynamite from 750~3000 kilograms which were set at the depth of 80 meters in the hole with an aperture of 12 inches, and the sources were located on the northern and southern W-E line from the west to the east. We get 6 kinds of data from this experiment, including：1) the wide-angle reflections of Texans; 2) the N-S seismometer arrays; 3) the seismic network of Central Weather Bureau(CWB) and Institute of Earth Science(IES); 4) the seismic array of Reftek 130(RT130) from IRIS in TAIGER project; 5) the short period of Ocean Bottom Seimometer(OBS) array in the Taiwan Strait; 6) the temporary seismic array in mainland China.
In this study, we handle the data from 3 W-E transects, 2 N-S transects and Taiwan Strait, and simulate the structure model from the first arrival time and more obvious reflections of these data by Ray-tracing method. The preliminary results are as follows：1) It is a standard layered structure beneath western Taiwan and the thickness of crust is 30 kilometers; 2) The crust thickens and becomes more than 40 kilometers in the mountain area, but it is narrow and deep here; 3) The structure beneath Hsuehshan Range and Central Mountain Range are different; 4) There are some boundary faults as deep as to the lower crust, especially the Li-shan fault; 5) The distribution of the Moho depth is basically thicker in the north, shallower in the south and getting deeper and deeper from the west to the east, but finally getting shallower rapidly in the area of Coast Range; 6) The Moho depth is shallower than 30 kilometers in the Peikang Height and deeper than 32 kilometers at the coast line of Fujian, there is no bulge in Taiwan Strait.
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