Preliminary volcano-hazard assessment for Makushin Volcano, Alaska

Abstract

Publication is required by Alaska Statute 4 1, "to determine the potential ofAlaskan land for production of metals, minerals, fuels, and geothermal resources; the location and supplies of groundwater and construction materials; the potential geologic hazards to buildings, roads, bridges, and other installations and structures; and shall conduct such other surveys and investigations as will advance knowledge of the geology of Alaska."

Eruption of Alaska Volcano Breaks Historic Pattern

“…Okmok is one of the most active volcanoes in the Aleutian arc with 14 confirmed eruptions since 1817 [Begét et al, 2005]. It consists of two nested calderas that formed about 12,000 and 2050 years ago, respectively.…”

Preeruptive inflation and surface interferometric coherence characteristics revealed by satellite radar interferometry at Makushin Volcano, Alaska: 1993–2000

“…Late Holocene lavas mark a return to more mafic compositions [ Miller et al , 1998]. Makushin sits ∼28 km west of the town of Unalaska/Dutch Harbor, the largest population center in the Aleutian islands and the principal fishing, shipping, and air transportation hub for westernmost Alaska [ Beget et al , 2000].…”

“…Geologic studies suggest that larger explosive eruptions occurred more than two dozen times during the last several thousand years, depositing widespread ash layers. In addition, a series of very large eruptions ∼8000 to 8800 years ago produced the present summit crater and generated numerous pyroclastic flows and surges, a debris avalanche, and lateral blast [ Beget et al , 2000; McConnell et al , 1997].…”

“…Simkin and Siebert [1994] reported small explosive eruptions (VEI 1) from the summit in 1980 and 1987, and a strong steam plume that did not contain ash in 1986. Beget et al [2000, p. 6] reported “In 1983 volcanic explosions were heard by nearby geologists but never correlated with specific deposits, and in 1996 ash deposits found at the summit and on the volcano's flanks were probably produced by a previously undocumented eruption in 1995 [ McConnell et al , 1997]”.…”

“…To follow up the possibility of an eruption during the mid 1990s [ Beget et al , 2000; McConnell et al , 1997] that might correlate with the uplift detected with InSAR (see section 2.1), we conducted a comprehensive search of all available information for reports of eruptive activity at Makushin between 1993 and 2000. Neal et al [1996] reported possible phreatic explosions on 14 and 23 September and 5 November 1993, based on aircraft pilot reports of possible ash clouds above the volcano, a sulfurous smell, and a dark discoloration of snow near the volcano's summit.…”