Volcanoes & Earthquakes

Monitoring Uses and Justification

Earthquake occurrence is common in the SWAN parks and region. This is a result of the Pacific plate moving in a northwest direction and subducting beneath the North American plate in southern Alaska, the Alaska Peninsula, and the Aleutian Islands. This plate boundary is responsible for most of the earthquakes occurring in this region. The location and magnitude of seismic events could be significant in terms of human health and safety and landscape change (mass movement).

There are 17 active volcanoes within the SWAN parks and region. Explosive volcanic eruptions, such as Katmai’s Novarupta in 1912, can catastrophically disturb hundreds to thousands of square miles of landscape, profoundly affecting fluxes of water and sediment. Vegetation can be defoliated, buried, or removed, and the landscape can be mantled with tephra (airborne volcanic ejecta ranging from ash to small blocks of rock). Rivers, lakes, and valleys can be partly or completely filled with pyroclastic debris, or massive deposits from debris avalanches and pyroclastic flows.

See the Protocol Development Statement for more information.

November 18, 2006 overflight of Fourpeaked Volcano. Plucinski, Tim; AVO; USGS.

Crater Lake, Mt. Griggs (upper right) and the Valley of Ten Thousand Smokes (upper center), Katmai National Park and Preserve. August 8, 2007. B. Giffen.