The characteristics of geothermal field along the Dali-Ruili railway in western Yunnan Province and their implications for geo-engineering

The available hot-spring data show that the geothermal field along the Dali-Ruili railway in western Yunnan Province has different subareas. The authors studied the distribution characteristics of igneous rocks, active faults, earthquakes in history and other related geophysical fields, such as MT and P wave velocity in the crust in this area. The results show that the distribution of the middle/high geothermal subareas is spatially well consistent with that of the igneous rocks and the active fault system. It is also concluded that there are three types of hot springs based on the caloric origin in this area, i.e., magma type, deep circle through deep-cut fault type and magma-deep circle type. Studies also show that there is spatial correlation between the distribution of the hot springs and that of the earthquakes in history. An integrated analysis of all the data obtained has led the authors to believe that the geo-thermal field in this area can act as an index for the estimation of the geo-engineering stability.