Application of Geophysical Methods to Permafrost in China
Yu Qi-hao, Cheng Guo-dong(State Key Laboratory of Frozen Soil Engineering, CAREERI, CAS, Lanzhou Gansu 730000, China)
Modern geophysical methods and techniques play an important role in investigating and studying permafrost. In China the application of geophysical methods to permafrost began from the early 1960 s. Since, it develops from single and simple methods to integrated methods to investigate different kinds of frozen soils, from getting single geophysical parameter to multi-parameters to reflect the general characteristics of frozen soils. Through more than 40 years hard working, great progress has been made in study and application of geophysical techniques in permafrost regions, especially in continuously improving the ability and precision in distinguishing frozen soils, and get some important information and parameters about frozen soils. The application of modern geophysical methods has become one of the key methods in investigating the state and three-dimensional properties of permafrost and monitoring the permafrost change and development. In this paper the foundations, based on which geophysical methods can be used in permafrost exploration, the development of geophysical technique in recent years; the great improvement of ability of resolving practical problems, the precision in distinguishing frozen soils; and the advantage and disadvantage of these methods are described. And farther more, this paper points out the large gap between China and the other countries and the scientific application abroad. What problems exist, what should be paid attention to and what should do in China in the future are also put forward.