Locations of seven MT sites (crosses sign) covering an area of 3 km × 4 km in Mae Chan district, Chiang Rai province, Thailand. Geological rock units and topography are plotted as the background on this map. Y1 and Y4 are the hot spring locations found at the river bed. Y2 is the drilled hole , and Y3a and Y3b are the hot springs found at the surface. Additional hot springs are also found around the north of MCH3 but are not shown.