Event Name : Veniaminof 2006/3
|Start:||March 3, 2006 ||Observed|
|Stop:||November 2006 ||Observed|
|Tephra plume: ||
|Central eruption: ||
|Minor explosive eruption: ||
|MaxVEI: ||1 ||
|ColHeight: ||2300 m ||
From the Smithsonian Institution (2006, v. 31, n. 3): "On the morning of 3 March 2006 ash again rose a few hundred meters above the intracaldera cone, drifted E, and dissipated rapidly. Ashfall was expected to be minor and confined to the summit caldera. Seismicity was again low and did not indicate that a significantly larger eruption was imminent. Over the week of 5-10 March, seismicity was low but slightly above background.
"On the morning of 10 March, AVO received a report from a pilot of low-level ash emission from the intracaldera cone. Clear web-camera views on 9 March showed small diffuse plumes of ash extending a short distance from the intracaldera cone. The Anchorage Volcanic Ash Advisory Center (VAAC) reported a steam/ash plume noted on web-cam and satellite on 13 March 2006 at 0500Z (12 March 2006 at 2000 hours local), moving NNW at 9.2 km/hr and falling to the land surface. Web-cam images on 22 March showed a very diffuse steam-and-ash plume that was confined to the summit caldera, and on 24 March showed a steam-and-ash plume drifting from the summit cone at a height of less than 2.3 km. This level of activity was similar to that on 23 March, but higher than activity on 21 and 22 March, when a very diffuse steam-and-ash plume was confined to the summit caldera.
"The flow of seismic data from Veniaminof stopped on the evening of 21 March 2006, and the problem was expected to continue until AVO staff could visit the site to repair the problem. Absent seismic data, the volcano could potentially still be monitored in other ways such as using web-camera and satellite images. Imagery was obscured by cloudy weather after 21 March. On 26 March 2006, a pilot reported a small ash plume rising above the volcano. Low-altitude ash emissions from Veniaminof were visible during 31 March to 7 April. On 6 April, a pilot reported an ash plume at a height of 3 km. AVO stated in its weekly report of 14 April 2006 that the seismicity at Veniaminof remained low but above background. Internet camera and satellite views had been obscured by cloudy weather, and AVO lacked new information about ash clouds or activity."
Continued activity was summarized by the Smithsonian Institution (2006, v. 31, n. 8): "Intermittent, very small-volume steam and ash bursts from the intra-caldera cone have been typical of this volcano intermittently over the past few years, and this pattern continued. The previous report mentions several minor bursts of ash, particularly on 13 June 2006 and 7 September, and minor white plumes through mid-September. This report discusses the interval 8 April through 15 September. Seismicity during this interval was nearly always low, although it often rose above background.
"Clouds obstructed visibility during 7-14 April. For the duration of April and June, activity remained low with few steam plumes containing minor amounts of ash. On 30 May a weak daytime thermal anomaly was recorded, possibly due to solar heating inside the dark intra-caldera cone. Intermittent clear weather on the week ending 9 June indicated weak steam plumes.
"On 13 June an ash emission rose to a height estimated at ~ 600 m above the summit area, as reported by a passing aircraft. Transient plumes were seen on satellite imagery during the week ending 21 July.
"During the week ending 28 July, an AVO field party flew over the summit and observed typical steaming from the intra-caldera cone with no signs of recent ash emissions. Satellite and web camera views during occasional clear periods showed no other signs of activity. Occasional satellite views during clear weather failed to disclose new ash emissions during 28 July through 15 September.
"AVO noted a slight increase in seismicity starting 2 August but in the subsequent weeks it again returned to low levels. Available satellite and camera views continued to reveal occasional small white plumes through 15 September."
Steam plumes without ash emission continue to be observed at Veniaminof, as of this writing (March 21, 2007).
McGimsey and others (2011) report that by January 2007, the intracaldera cinder and spatter cone was producing only minor, diffuse steam plumes that rose at most a few hundred meters above the vent. * * * Foloowing several weeks of cloudy weather, clear web camera views on the morning of February 16, 2007, revealed vigorous steaming from the intracaldera cone [see fig. 22 in original text]. Clouds and a short camera outage prevented observations for several days, and then on the morning of February 20, a clear view showed little to no steaming from the cone. Minor steaming was visible through February 24 when weather permitted, and by February 25, no signs of steam emissions were apparent in web camera images. Over the next couple of months, intermittent clear views of the volcano in either web camera images or in satellite images showed that occasionally minor steam plumes were issuing from the intracaldera cone. Seismicity had decreased to background levels several months prior, and the last ash-laden plume visible in web camera images was on November 2, 2006. The last thermal anomaly visible in satellite images was on July 5, 2006. Ground observers and pilots reported no unsual activity in recent months, and therefore on April 26, 2007, AVO lowered the Aviation Color Code/Volcano Alert Level to GREEN/NORMAL. Based on historic patterns of eruptive behavior, AVO anticipated continued steaming from the cone. Indeed, Veniaminof continued to steam intermittently throughout 2007."
For additional photographs and observations of this event, please see: Neal, C.A., McGimsey, R.G., Dixon, J.P., Manevich, Alexander, and Rybin, Alexander, 2009, 2006 Volcanic activity in Alaska, Kamchatka, and the Kurile Islands: Summary of events and response of the Alaska Volcano Observatory: U.S. Geological Survey Scientific Investigations Report 2008-5214, 102 p., available at http://pubs.usgs.gov/sir/2008/5214/