Adventures on Katmai

In June of 1912, Alaska’s Mount Katmai erupted with all the force of Mother Nature. As was the case with Kilauea in Hawaii, the eruption offered an incredible opportunity for scientific study. Despite this fact, four years passed before the first expedition to the volcano. The party was led by R. F. Griggs of the National Geographic Society.

Grigg’s mission sparked interest in the Geophysical Laboratory to undertake a similar study of the mountain. Between the years 1918 and 1923, C. N. Fenner, E. G. Zies, and E. T. Allen headed the Laboratory’s own investigation to Mount Katmai and specifically the volcano’s Valley of Ten Thousand Smokes.

At the Valley of Ten Thousand Smokes, Fenner, Zies, and Allen collected rocks, looked into fumerole encrustations, measured the temperatures of hot springs, helped in geologic mapping, and aspirated exhalations for insoluble gases. The conclusions the three men formed from this data were vast and detailed.

The scientists reasoned that the origin of the vast sheet of siliceous rocks at Katmai was not lava but pyroclastic, having been ejected as rhyolitic pumice through the broken valley floor. Fumeroles measured 100 to 650 degrees Celsius. They were discovered to decrease in heat over time and had a deep-seated origin.

Some of the best results Fenner, Zies, and Allen found concerned the mineralogy of Katmai’s rocks. It was deduced that the mineralogy of the Valley’s encrustations changed as temperature decreased, and because many minerals of economic value were formed, a relationship of ore deposits to volcanic exhalations was subsequently established. In addition to these findings, the hybrid nature of the rock samples led Fenner to believe that superheated rhyolite magma had melted pieces of old andesitic lavas and integrated them into the erupted pumice and ash.

Overall, the work that resulted from the Geophysical Laboratory’s expedition was extensive and ground-breaking. The detailed investigative work in mineralogy and geology established the value of a multidisciplinary approach to solving geological problems.