岫岩陨石撞击坑结构高精度地震探测研究

我国的岫岩陨石撞击坑位于辽东半岛北部低山丘陵地区,直径1.8 km,保存完好,已被多方面的证据证实为陨石撞击坑.陨石的撞击和此后的沉积作用在坑内形成了特殊的地球物理场,使坑内与坑外的介质在速度、密度等方面存在差异.本次通过采用反射和折射地震相结合的探测方法,利用陨石撞击所形成的岩石的地震波速度和波阻抗差异,获得了陨石坑...

High-resolution seismic exploration of Xiuyan impact crater structures

The Xiuyan impact crater with a rim-rim diameter of 1.8 km is located at northern hills in the Liaodong peninsula, Liaoning province, China. It is reserved well and confirmed to be a meteorite impact crater. A special geophysical field resulted from the meteorite impact and subsequent deposit at the crater makes different medium velocity and density between inside and outside of the crater. In the project, velocity structures, stratum structures and whole configuration of the crater are gotten using the differences of seismic velocity and wave impedance from the combined exploration of reflection and refraction. Based on the reflection features, the crater body formed by the direct impact has a diameter about 1.8 km, and a depth about 800 m, and the depth affected by the impact is about 1.4 km. The crater structure is divided into 3 parts, slow deposit area, rapid deposit area and affected area. According to the seismic velocity features, the velocity at the crater center where the depth is 800 m reaches 7.0 km/s, the isoline of 7.0 km/s is consistent with the crater configuration, but the velocity reached 7.0 km/s at the depth of 500~600 m in the edge of the crater. The structure of the crater body and the physical property of rocks confirm further the Xiuyan crater origin from meteorite impact.