Okmok - Historic eruptions

Reported Activity

start date	end date	title	description	icon	date limit	importance	link
1805-00-00		Okmok: 1805	Hantke (1951) wrote that there was "an eruption on Umnak" in 1805. It is difficult to say if this eruption occurred and was from Okmok. Grewingk (1850, translated 2003 by Fritz Jaensch) who compiled accounts of many travelers to the region during the time period 1760-1850, makes no mention of this eruption. Langsdorff (1812), who was present in the area from 1803 through 1807, also writes "The active volcano on Umnak * * * has been totally still for a fairly long time" - apparently discrediting ... More information	information.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=160&page=basic
1817-03-02	1820-3-1	Okmok: 1817 - 1820	Grey (2003) has compiled and studied information about the 1817 Okmok eruption. From her thesis: "The first confirmed activity at Okmok was a large explosive eruption around 1817. There is a discrepancy as to the exact date and duration of the eruption. Veniaminov (1840, translated by Lydia T. Black and R.H. Geoghegan, 1984) maintains it was March 2, 1817; Postels (in Lutke, 1836) alleges it occurred on March 1, 1820. Grewingk (1850, translated 2003 by Fritz Jaensch) favors Veniaminov's assertion ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=162&page=basic
1824-00-00	1830-00-00	Okmok: 1824 - 1830	From Grey (2003): "According to Grewingk (1850, translated 2003 by Fritz Jaensch), Lutke reported an eruption on the northeast end of Umnak Island, during which a 'mountain ridge opened up' in 1824 and was still 'smoking' in 1830. He also says that Postels (in Lutke, 1836) erroneously reported the activity as stretching along the northwest coast, but does not mention on what basis this presumption of error is made - perhaps the eruption was merely viewed from off the NW coast and appeared nearer ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=163&page=basic
1878-00-00		Okmok: 1878	From Grey (2003): "A new crater is reported to have formed within the caldera in 1878 (Hantke, 1951), accompanied by earthquakes and a tsunami (location unknown). This could refer to the birth of Cone A, but since Hantke offers no additional information or references to support this notion, the report is apocryphal at best. It is intriguing to note that eruptions are also reported at Vsevidof, on the southwestern end of Umnak Island, in 1817, 1830, and 1878 (Miller et al., 1998). Of particular ... More information	asterisk_yellow.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=164&page=basic
1899-00-00		Okmok: 1899	From Grey (2003): "An explosive eruption is said to have occurred in 1899 (Dunn, 1908). Robert Dunn (1908) details his visit to Umnak Island while 'vulcaneering' in the Aleutians. After landing on the beach south of Cape Aslik [see figure 4.2 in original text], he hiked up the slope past Jag Peak to the top of the ridge (the WSW rim), where he first laid eyes on the caldera: 'Below, yawned simply one titanic crater, five miles from far side to far side, if one single inch. Strewn on its floor, ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=165&page=basic
1931-03-21	1931-5-13	Okmok: 1931	From Grey (2003): "Jaggar (1931) relates the journal entry of Mrs. Esther Wendhab, who tended seismographs in Dutch Harbor, on March 23, 1931: 'Captain Nelson of the Eunice reported a volcano smoking terribly with thick black fumes, where before he had only observed white steam, at Tulik on Umnak Island. He passed it March 21 and so unusual was its action he believes it is about to erupt. There was no record on the seismograph.' "This eruption is reported to have continued at least until ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=166&page=basic
1935-12-20		Okmok: 1935	A UP article recounts a probable eruption of Okmok, on December 20, 1935. "Seward, Alaska - Dec. 30 - (UP) -- Violent eruption of Mt. Tulik, active volcano on nearly uninhabited Umnak Island in the Aleutian Archipelago was reported today by Capt. Chris Trondsen of the steamer Starr, who reached Seward after a cruise along the islands. "Capt. Trondsen said great streams of flaming lava were pouring out of the cone of Mt. Tulik Dec. 20, and the sky for miles was red with the glare. There are ... More information	asterisk_yellow.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=559&page=basic
1936-00-00		Okmok: 1936	Coats (1950) reports smoke at Okmok in 1936.	asterisk_yellow.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=167&page=basic
1938-07-00		Okmok: 1938	The Anchorage Daily News reported on October 20, 1938, that U.S. Coast and Geodetic Survey crews of the ships Pioneer and Surveyor had reported "Mount Tulik on Umnak Island" active during the summer of 1938. The deeply glaciated nature of Mount Tulik (Coats, 1950; Miller and others, 1998) indicates that it has not been active within historic time. Eruptions attributed to Tulik are almost certainly eruptions at Okmok instead. Coats (1950) reports this eruption as occurring in October; this date ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=168&page=basic
1943-06-00		Cone A: 1943	From Grey (2003): "Servicemen stationed at Ft. Glenn [U.S. Army base established on Umnak Island in 1942 and decommissioned in 1950) would occasionally trek into Okmok caldera looking for adventure as evidence by the occasional spent shells found on the caldera floor. One sunny afternoon in June 1943, two GI's drove up to the caldera rim near the base of Tulik cone and rappelled down to the crater floor, probably between the sites of the small intracaldera glacier and Cone F (Keller, 1976 and ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=169&page=basic
1945-06-01	1945-12-00	Cone A: 1945	From Grey (2003): "The 1945 eruption was fairly well documented (Miller et al., 1998; Robinson, 1948; Wilcox, 1959; Byers, 1947). Robinson gave a detailed account of his visit to Okmok at the request of Lt. Gen. Delos C. Emmons, Commanding General of the Alaskan Department, who was concerned for the safety of Ft. Glenn army base. The eruption is believed to have begun on June 1, when a sharp earthquake was felt at Ft. Glenn. Cloud cover delayed the first observation until June 4, when pilots ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=170&page=basic
1953-03-02		Cone A: 1953	From Snyder (1953): "On March 2 [1953] Richard McDonald, U.S. Geological Survey seismologist stationed at Adak, rode a Navy plane from Kodiak to Adak and back. He reported steam rising from Pavlof, Shishaldin, Makushin, and a small cone within Okmok Caldera on this day."	information.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=457&page=basic
1958-08-14	1958-9-2	Cone A: 1958	From Grey (2003): "After a 13-year hiatus in reported eruptive activity, Okmok returned to life the evening of August 14, 1958. Eruptive activity was first reported by sheep ranchers on northeastern Umnak, and by Reeve Aleutian Airways personnel on the island (Anchorage Daily News/Times, August 15, 16, and 19, 1958). Reeve pilot Everett Skinner flew from Dutch Harbor to Nikolski on the SW end of Umnak Island on the morning of August 15 and observed an ash plume over Okmok reaching 5.5-6.0 km ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=171&page=basic
1960-10-15	1961-4-15	Cone A: 1960 - 1961	From Grey (2003): "An eruption that began in October, 1960 produced enough ash to reach Chernofski Sheep Ranch on western Unalaska Island [see figure 4.8 in original text] (Holmes, 1994). According to John Reeder of the Alaska Division of Geological & Geophysical Surveys, who interviewed Milton Holmes, resident Chernofski rancher, 'there were times when Milton could see lava shooting above the Okmok caldera only to fall back in. When the wind was not blowing, a red glow could be seen from the ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=172&page=basic
1981-03-24	1981-3-24	Cone A: 1981	From Reeder (1987): "During the morning of 24 March 1981, pilot Harald Wilson observed a growing ash and steam eruption plume over Okmok Volcano. Harold was flying his Peninsula Airways, Inc. Navaho from Cold Bay to Dutch Harbor of Unalaska Island. His initial observation of the eruption plume was about 1000 local time (=GMT -10 h.) when he was about 80 km NNW of Dutch Harbor at a 2,600 m altitude. The plume of mixed steam and ash had reached an approximate 2,800 m altitude and was still growing. ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=173&page=basic
1983-07-08	1983-7-8	Cone A: 1983	From Grey (2003): "A 100 km long plume was recognized in one NOAA 7 image at 1716 local time on July 8 [1983] (0216 UTM on July 9), but was not seen on images 12 hours earlier or later. This was apparently only a brief puff of ash and steam, accompanied by sulfurous gases, as reported by Aleutian Air pilot Tom Madsen (Reeder, 1986)." From Reeder (1986), describing what Tom Madsen saw on his flight to Atka from Dutch Harbor on July 8: "Upon reaching Driftwood Bay, which is about 23 km WNW ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=175&page=basic
1986-11-18	1988-2-26	Cone A: 1986 - 1988	From Miller and others (1998): "A commercial pilot reported a steam and ash plume above a cinder cone (probably the 1945 cone) in the southwestern part of the caldera on November 18, 1986. Another small ash eruption occurred from the same cone on January 5, 1987 about 13 hours after a shallow, magnitude 6.6 (Ms) earthquake struck 130 km south of Okmok. A small pyroclastic flow was produced on the southeast flank of the cone and ash emission from the cone continued intermittently from January ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=176&page=basic
1997-02-13	1997-5-23	Cone A: 1997	From Grey (2003): "The latest eruption at Okmok began on or shortly before February 11, 1997 and originated at Cone A. An excellent synopsis of the eruption is found in U.S. Geological Survey Open-File Report 99-448 (McGimsey and Wallace, 1999) and is paraphrased here. Possible precursory activity included a steam plume observed by a passing pilot on November 11, 1996. The next report was of a dark plume, witnessed by a pilot and passengers en route from Atka to Dutch Harbor on February 11, ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=177&page=basic
2001-05-11	2001-5-15	Okmok: 2001	McGimsey and others (2004) report on an earthquake swarm detected May 11, 2001, at Okmok Volcano: "At 8:00 ADT (16:00 UTC) on the morning of May 11, 2001, AVO seismologists detected on the Makushin seismic network a swarm of earthquakes occurring under Okmok volcano prompting AVO to release an Update at 17:00 ADT (01:00 UTC). The events were ML=2.0-3.6 - too small to be felt by nearby residents - and determined to be possibly of volcanic origin. Satellite observations revealed no volcanic activity ... More information	information.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=178&page=basic
2008-07-12	2008-8-00	Okmok: 2008	From Neal and others (2011): "Okmok Volcano, a 10-km (6.2-mi) diameter Holocene caldera system in the central Aleutians [fig. 14; imageid 13283], began a protracted explosive eruption on July 12. The opening explosions consumed a portion of intracaldera Cone D within the east-central sector of the caldera, reaming several new craters into the caldera floor. Eruptive activity began only a few hours after a subtle increase in the rate of earthquakes followed by a short swarm sequence, both noted only ... More information	exclamation.png	ye	50	http://www.avo.alaska.edu/volcanoes/activity.php?volcname=Okmok&eruptionid=604&page=basic