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

Okmok reported activity





Event Name : Okmok 2100000 yBP

Start: 2100000 (± 200000 Years) Years BP K-Ar

Lava flow: BibCard
Eruption Type:Effusive
Eruption Product: basalt BibCard

Description: From Miller and others (1998): "Construction of the pre-caldera volcano began in late Tertiary or early Quaternary time. Two whole-rock K-Ar analyses of a sample of basaltic lava are 1.7+/-2 and 2.1+/-2 m.y. (Bingham and Stone, 1973). Basaltic flows and pyroclastics compose most of the older rocks (unit Qbm, fig. 67 [in original text]); flows are more voluminous than pyroclastic deposits (see Byers, 1959, plate 41)."

"Flows and pyroclastic beds dip radially from the caldera at less than 5 degrees in most sectors, except for local steepening and reversal of dips at former vents. Such radial dips suggest that the older complex was a central volcano with parasitic vents."

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.