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利用３９４７３条Ｐｎ射线的走时资料，采用地震层析成象方法反演中国大陆上地 幔顶部Ｐｎ速度结构．反演结果表明，中国大陆Ｐｎ平均速度为８．０ ｋｍ／ｓ，横向速度变化 量从一０．３０ ｋｍ／ｓ至＋ ０．３５ ｋｍ／ｓ．速度超过８．２ ｋｍ／ｓ的地区主要围绕在青藏高原的周边， 如：准噶尔盆地、塔里木盆地、柴达木盆地及四川盆地；速度偏低的地区主要分布在川 滇西部，山西地堑及渤海湾，在雷州半岛及其以北的粤桂交界处可能存在速度低至７．８ ｋｍ／ｓ的低速区，总体看来，构造上稳定的克拉通地台具有较高的Ｐｎ速度，而构造上活动 的地区往往速度较低；挤压环境具有较高的Ｐｎ速度，而拉张盆地或地堑则具有速度低 的特点．在青藏高原东南部，快波速方向呈现旋转变化趋势，这可能与高原物质受印度 板块的碰撞挤压而向东南方向逃逸有关；渤海湾周围也有显著的各向异性，反映了该 地区存在地壳扩张及可能的岩浆活动．
Using the time-history data of 39,473 Pn-ray, the Pn velocity structure of the upper mantle in the Chinese mainland was retrieved by seismic tomography. The inversion results show that the average velocity of Pn in mainland China is 8.0 km / s and the lateral velocity varies from 0.30 km / s to + 0.35 km / s. The areas exceeding 8.2 km / s are mainly located in the periphery of the Qinghai-Tibet Plateau, such as Junggar Basin, Tarim Basin, Qaidam Basin and Sichuan Basin. The areas with low velocity are mainly distributed in western Sichuan, Yunnan, In the Bohai Bay, there may be a low speed zone with a velocity as low as 7.8 km / s at the junction of the Leizhou Peninsula and the north of Guangdong and Guangxi. In general, the structurally stable craton station has a high Pn velocity. However, Areas that are tectonically active tend to be slower; the compression environment has a higher Pn velocity, while the stretch basin or graben has the characteristics of low velocity. In the southeastern part of the Tibetan Plateau, the trend of fast-wave rotation shows a rotation trend, which may be related to the plateau collision of plateau with southeastward escape due to the collision of plateau; the significant anisotropy around Bohai Bay also reflects the existence of crustal dilatation And possible magmatic activity.