Valley of Ten Thousand Smokes

Although never permanently inhabited by humans, it served as a pass for the Alutiiq people, as well as animals such as grizzly bears.

5, resulted from the collapse of the caldera at Mount Katmai and movement within the magmatic plumbing system.

[7] In places deep canyons have been cut by the River Lethe, allowing observers to see the ash flow strata.

[9] Basement rocks in the area consist of the Late Jurassic Naknek Formation, which is composed of siltstones, and arkosic sandstones 1.7–2 km thick deposited in a marine shelf and submarine fan delta environment during the Oxfordian-Tithonian.

The ignimbrite consisted of 9 separate packages of pumiceous pyroclastic flow deposits, radiating outward 9 km, and which filled 11 km3 of the valley to a depth of 100–200 m in the upper portion and 35 m in the lower over the span of 16 hours.

The ignimbrite is noted for its fumaroles, phreatic craters, welded tuff, and flattened fiamme.

Episode II consisted of a second Plinian dispersal, but one consisting of dacite tephra, depositing 4.8 km3 of layers C and D. Episode III was also a Plinian dispersal of dacite tephra depositing 3.4 km3 of layers F and G.[5]: 4–5, 18–20, 45–48, 143–146 The explosion from the eruption was heard as far away as Fairbanks and Juneau, while earthquakes continued until mid-Aug. Ball lightning near the ground was noted in addition to regular thunder and lightning, rare in South Alaska, while severe static disrupted wireless transmissions.

In 1918, Jasper Sayre and Paul Hagelbarger noted 86 vents with temperatures greater than 190 °C, the hottest being 432 °C.

[5]: 4–5, 18–20, 45–48, 143–146 The Katmai Peninsula in general, and the valley in particular, were used by NASA and the USGS to geologically train the Apollo astronauts in recognizing volcanic features, landforms and materials, especially fumaroles and vents.

"Playing the Moon game", involved pairing up astronauts and placing them in a location with very little prior information.