Okmok 12000 yBP

Start: 12000 yBP [1]

Stop: 2050 yBP ± 50 Years [1]

Event Type: Effusive

Event Characteristics:
  • Lava flow [1]
  • Tephrafall [1]

Description: From Beget and others (2005): "In addition to eruptions within the caldera, more than 20 small cinder cones and lava flows occur high on the upper north and northeastern flanks of the volcano and around the caldera rim, and at least five flank cones lie on the southwest flank of the volcano. These features are relatively uneroded and most are likely post-glacial in age and also pre-date the most recent caldera-forming eruption and so are less than 12,000 years old. The largest flank eruption produced a 200-meter-high lava spatter cone and a voluminous lava flow that forms cliffs at Cape Aslik (fig. 2 [in original text]). The lava flow covers more than 15 square kilometers on the west flank of the volcano, involves about 0.5 cubic kilometers of lava, and is locally buried by tephra produced during the younger caldera eruption about 2,000 years ago."

References Cited

[1] Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska, 2005

Beget, J.E., Larsen, J.F., Neal, C.A., Nye, C.J., and Schaefer, J.R., 2005, Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2004-3, 32 p., 1 sheet, scale 1:150,000.
map sheet 53.2 MB

Complete Eruption References

Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska, 2005

Beget, J.E., Larsen, J.F., Neal, C.A., Nye, C.J., and Schaefer, J.R., 2005, Preliminary volcano-hazard assessment for Okmok Volcano, Umnak Island, Alaska: Alaska Division of Geological & Geophysical Surveys Report of Investigation 2004-3, 32 p., 1 sheet, scale 1:150,000.
full text of report 3.4 MB
map sheet 53.2 MB
× Instrument data