REPORTS
A Formation Mechanism of Water Temperature and Water Quality in The Lake Katanuma in The Narugo Volcano
1995 Volume 18 Issue 10 Pages 829-836
Details
1995 Volume 18 Issue 10 Pages 829-836
The Lake Katanuma in the Narugo Volcano, a crater lake with strong acid water influenced by volcanic activity, was surveyed to elucidate the heat flux in the lake and the formation mechanism of acid lake water. The results are to be made use of as basic data for the prediction of erruption and the prevention of disaster. The lake forms the ellipse of 462m E-W length and 326m N-S breadth, and forms 1,380m shore line. The surface area is 1.26×105m2, the maximum depth is 21.3m and the volume is 7.48×105m3.
In the bottom of the Lake, there are some high temperature zones where warm water springs out. Those zones are situated in the deepest, the south and the northeast basins of the Lake. The ground temperature gradient in the south high temperature zone amounts to 0.245-0.391°C·cm-1.
Volcanic gasses evolve out of the deepest portion, which forms some limited depression. The volcanic gas dissolves in under-ground water vein in the shallow part under the bottom and forms the acid water by means of auto redox reaction of H2SO3, and at the same time, supplies heat at a rate of 372×10-6cal·cm-2·s-1.
