Abstract: A method of prospecting for the concealed active fault by simultaneous measuring both ²¹⁸Po and ²¹⁰Po is introduced.It is a radioactive prospecting.The concentration of radon near the fault can be determined from the activities of its daughters ²¹⁸Po and ²¹⁰Po.At the fault,there is a good passage for gases,and the radioative gas from crustal depths can be easy to get to the surface.As a result,the level of the radioactivity there is quite high,but low at both sides far from there.The observational points where the activ.ity of ²¹⁸Po and ²¹⁰Po is much higher than their background values can be regarded as the position of the hidden fault we want to seek.A number of observations at the known faults and hidden active ones indicate that seeking hidden active faults on certain conditions of their outcrops by measuring ²¹⁸Po and ²¹⁰Po is an effective,efficient-and hopeful way.

Key words: ²¹⁸Po, ²¹⁰Po, Daughter, ²²²Rn, Activity, Hidden activy fault, Hebei

摘要： 用²¹⁸Po与²¹⁰Po对比测量寻找隐伏活断层。利用Rn衰变子体的放射性活度,测量断层周围Rn浓度的变化。在断层处由于有较好的气体通道,深部的放射性气体易于运移地表,使地表的放射性测值增高。而距断层较远处,放射性测值较低。根据放射性测值的变化,明显出现异常的部位,就是所要寻找的隐伏活断层的地面位置。 通过在已知断层以及隐伏活断层的几次观测表明,在一定条件下.用²¹⁸Po与²¹⁰Po对比测量寻找隐伏活断层,探测效率较高,效果较好,是有前途的测试方法。

关键词: ²¹⁸Po, ²¹⁰Po, 衰变子体, ²²²Rn, 放射性活度, 隐伏活断层, 河北