First arrival seismic tomographic imaging test of the near-surface velocity structure of central uplift in the Qiangtang basin, Qinghai-Tibet Plateau

In 2007 and 2008 two reflection seismic profiles that linking up and crossing the central uplift of the Qiangtang basin were acquired in Tibetan Plateau. The aim of writing this paper is to take advantage of these probe data and test the first arrival tomographic method to imaging the near-surface velocity structure of the central uplift in the Qiangtang. The results indicate that the first arrivals are clear in the recordings of high dynamite shots, and the detailed shallow structure trend emerges at long array receivers. The tomographic travel-rays assemble where the structure is complex underground. The tomographic image reveals the undulate character of the high velocity structure both vertical and horizontal. And its thickness has negative correlation with the age of the outcrop. All the research testifies that the first arrival seismic tomographic imaging method can provide more detailed near-surface velocity structure information.