The Nature of the Katmai Volcanic Gases and Encrustations

Abstract

THE fumarole activity following and continuing after the great Katmai eruption of June, 1912, has provided south-western Alaska with the first among the natural wonders of the world. The volcanic gases force their way to the surface over an area of more than fifty square miles. This area is covered with volcanic ash and pumice, largely distributed by an enormous flow of mud following the explosion of the Novarupta volcano, but preceding the outburst of Katmai ten miles to the eastward. The relatively coarse ash and pumice from Novarupta were not ejected to any considerable distance, but, falling locally, quickly melted the snow on the mountains, and, with the rainfall accompanying the eruption, slid down into the adjacent valleys, forming a viscous mass which poured down the Bering Sea slope of the peninsular axis for a distance of more than fifteen miles.