【摘要】 利用在青藏高原羌塘中部(TITAN-I项目)部署的54套流动地震台站于2008年9月至2010年11月期间所记录的506个远震事件,共9532个高质量的P波初至走时数据运用FMTT方法进行层析成像反演,获得了羌塘中央隆起带下200km的深的地壳和上地幔三维P波速度结构.结果表明:羌塘中央隆起带的南北两侧块体的岩石圈速度结构明显不同.E-W向剖面(33°和33.5°N)显示,其两侧的岩石圈结构尺度整体上存在明显差异,南北羌塘地壳整体上呈E-W向高速异常,但北羌塘的高速异常已经延伸到岩石圈地幔,且本研究区内北羌塘盆地的东部有明显的低速异常块体.而沿N-S向的两条剖面(88.5°和89.5°E)显示,羌塘中央隆起带为一明显的边界构造断裂带.更多还原

【Abstract】 We have determined a detailed three-dimensional P-wave velocity structure of the crust and upper mantle down to a depth of 200 km beneath the central uplift belt of Qiangtang by applying Fast Marching Teleseismic Tomography(FMTT) to 9532 high-quality P-wave arrival times.The travel time data were determined by careful interpretations of original seismograms of 506 teleseismic events recorded by a network of 54 broadband stations deployed in the Qiangtang terrane on the Tibetan Plateau during September 2008 and November 2010.Our tomographic imaging beneath the central uplift belt of Qiangtang shows a deep boundary rupture structure for which the lithospheric velocity structure is significantly different on the northern and southern sides.Tomographic images along 33°N and 33.5°N show that lithospheric structures beneath the sides of the central uplift belt have different scales.The crust at the sides of the central uplift belt exhibits E-W trending high-velocity anomalies.However very low velocities are found within the crust beneath the northern Qiangtang basin overlying and high-velocity anomalies in the lithospheric mantle.Imaging along north-south profiles(88.5°E and 89.5°E) shows that the central uplift of Qiangtang is a significant tectonic boundary fault zone.更多还原