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

Moffett reported activity

MOFFETT LINKS

SAMPLES
EVENT SPECIFIC INFORMATION

Event Name : Moffett Intermediate Ash

Start: 6960 (± 100 Years) Years BP C-14 (raw)
Stop: 4460 (± 180 Years) Years BP C-14 (raw)

Tephrafall: BibCard BibCard BibCard
Eruption Type:Explosive
Eruption Product: andesite BibCard
ChemYes
Othermafic

Description: Waythomas and others (2003) tentatively identify Moffett Volcano as the source of the Intermediate Ash, observed on Adak Island and also called AD-4 by Kiriyanov and Miller (1997).

From Kiriyanov and Miller (1997): "AD-4 ash is 4-8 cm thick and consists of pumice gravel and lapilli with a maximum size of 3 cm, small amounts of gray clay- and silt-size materials and fine-grained sand, and a large amount of rock fragments 0.5-0.8 cm in size. The coarser material is concentrated in the middle of the ash layer. Distinctive features of this ash are a considerably large amount of rock debris (13%), absence of pyroxenes, and a very small content of green and brown hornblendes (1-2%). The inferred age of the ash is 4500-4600 14C years (Table 1 [in original text])."

From Okuno and others (2012): "The lntermediate tephra-fall deposit consists of pumice and lithic fragments with a cross-laminated ash bed. It is 43cm thick and contains a large amount of dense lithics with a maximum size (ML) of 3.8cm."

From Waythomas and others (2001): "A thick lapilli tephra deposit about the same age as the Intermediate Ash is present at locality 00CW06 northeast of Kanaga Volcano (fig. 9 [in original text]) but is not recognized elsewhere on Kanaga Island. Radiocarbon ages associated with Kanaga Island tephra T7 match those of the Sandwich Ash (fig. 13 [in original text]); however, the T7 deposits consist of massive sand-size felsic tephra with granule-size juvenile lapilli at the base (sec. 99CW75, fig. 9 [in original text]) or a single thin lapilli bed (sec. 99CW83, fig. 9 [in original text]) and do not exhibit the sequence massive gray fine ash/oxidized granule lapilli/massive gray fine ash that characterizes the Sandwich Ash on Adak Island. Thus, we are uncertain whether tephra T7 and the Sandwich ash are the same tephra deposit..."

Contact AVO Privacy Accessibility Information Quality FOIA
URL: www.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 G19AC00060 and G19AC00171.

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