AVO Logo
Site Map | FAQ |
Alaska Volcano Observatory
About Alaska's Volcanoes | Hazards from Alaska's Volcanoes | Map & Alphabetical List | Interactive Map | Eruption Search | Volcano Search 
You are here: Home > Volcano Information

Aniakchak reported activity





Event Name : Aniakchak Half Cone Upper Pumice

Start: 570 (± 40 Years) Years BP C-14 (raw)

Tephrafall: BibCard BibCard
Eruption Type:Explosive
Eruption Product: dacite BibCard

Description: From Bacon and others (2014): "Pumice-fall and pyroclastic-flow deposits from Half Cone are exposed in the north wall of the 1931 Main Crater 2 km to the south (fig. 13D [in original text]). Here, the cliff at the base of the section (fig. 13E [in original text]) is composed of >22 m of partly welded or indurated coarse pyroclastic-flow material, much like spatter-rich pyroclastic-flow deposits at Santorini (Mellors and Sparks, 1991), containing andesite bombs as large as 0.6 m x 2 m and similar in composition to Half Cone pyroclasts (59 weight percent SiO2). This unit is overlain by 13 m of pumiceous cross-bedded surge layers, 31 m of pumice-fall deposits, 5 m of Half Cone ca. 400 yr B.P. spatter agglutinate, and an 81-m-thick section of 1931 materials (Nicholson and others, 2011, their figure 3F). Dacite tephra older than the Pink Pumice and considered to have a Half Cone source, and which therefore may be correlative with proximal deposits at Half Cone and with the section exposed in the 1931 Main Crater, have weighted mean radiocarbon ages of 840+/-40 and 570+/-40 yr B.P. (tables 1 and 2 [in original text], lower and upper light pumice, respectively)."

Contact AVO Privacy Accessibility Information Quality FOIA
URL: avo.alaska.edu/volcanoes/activity.php
Page modified: March 30, 2017 14:36
Contact Information: AVO Web Team

twitter @alaska_avo
facebook alaska.avo
email Receive volcano updates by email: USGS VNS

This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137

Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey.