在山前广泛发育着冲积堆和洪积堆,它们向山前倾斜平原扩展开来,并且互相衔接和覆盖起来,因而在山前出现大片的呈扇状展开的所谓冲积洪积扇地区。这种水文地质类型的地下水,由于岩层倾伏,有良好的径流条件,所以一般都是淡水(含盐量小于1克/升),水量丰富,对供水有很大意义。对于这种类型地区物探在近十几年来已做过不少工作,其应用方法和解释推断方法也 Alluvial piles and alluvial heaps were extensively developed in front of the mountains. They expanded toward the sloping plain ahead of the mountain and joined and covered each other. As a result, large areas of fan-shaped so-called alluvial and alluvial fans appeared in front of the mountain. This type of hydrogeological groundwater is generally fresh water (salt content less than 1 g / l) due to its dip and good runoff conditions. It is rich in water and is of great significance for water supply. Geophysical methods have done a great deal of work in this type of area in the past ten years, and their methods of application and inference methods