【摘要】 本文根据北京地震台网的人工爆破资料,由莫霍界面的首波 P_n 的走时数据,经过松散层校正和高程校正后,采用改进的时间项法计算测点（台站和炮点）的时间项 t 和 V_pn,最后引进弹性薄板模拟莫霍界面的形状,得出北京地区莫霍界面深度等值线图.从该图可以明显看出全区趋势变化:西北部山区莫霍界面埋藏深,东南平原莫霍界面埋藏浅,向北西72°方向,向下倾斜约2°,全区平均深度约37公里.此外,莫霍界面下的 V_pn较为稳定.更多还原

【Abstract】 The contours of equal depths of the Mohorovicic Discontinuity underneath the Beijing area in North China are presented in this paper. They have been obtained on the basis of the Pn-travel time data of explosions recorded by the Beijing seismic network. The procedure of computation consists of three steps:1. Correction of the Pn-travel time for unconsolidated surface layers and also for station and shot elevations;2. Determination of the time-term of every observation point (stations and explosion sites) and Vpn, using the modified time-term method;3. Finally, simulation of the Moho-Discontinuity, by a thin elastic plate and then calculate the depths.It may be seen quite obviously from the depth contours a tendency that toward the northwest in the mountainous part of the area, the Moho-Discontinuity is deeper, but shallower toward the southeast. In the direction of 72° northwest, it dips about 2°.The average depth of the Moho-Discontinuity of the entire area is about 37 km. Besides, below it, the value of Vpn become more stable.更多还原