LAST UPDATE: 5 March 2010
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BEZYMIANNY - (55o58' 42"N 160o35' 12"E), 2,882 m, KAMCHATKA (Russia)
As of the 5th of March, the Kamchatkan Volcanic Eruption Response Team (KVERT) has reported that activity of the volcano continues and its aerosolic plumes could affect low-flying aircraft. Strong volcanic activity of Klyuchevskoi volcano obscures seismic data of Bezymianny last week. Strong fumarolic activity of the volcano was observed on February 24th and moderate - on February 22nd-23rd and 25th. Clouds obscured the volcano in the other days of week. According to satellite data, a thermal anomaly over the lava dome was registering all week.
Prior to its noted 1955-56 eruption, Bezymianny volcano had been considered extinct. The modern Bezymianny volcano, much smaller in size than its massive neighbors Kamen and Kliuchevskoi, was formed about 4700 years ago over a late-Pleistocene lava-dome complex and an ancestral volcano that was built between about 11,000-7000 years ago. Three periods of intensified activity have occurred during the past 3000 years. The latest period, which was preceded by a 1000-year quiescence, began with the dramatic 1955-56 eruption. This eruption, similar to that of Mt. St. Helens in 1980, produced a large horseshoe-shaped crater that was formed by collapse of the summit and an associated lateral blast. Subsequent episodic but ongoing lava-dome growth, accompanied by intermittent explosive activity and pyroclastic flows, has largely filled the 1956 crater.
The colour code at Bezymianny is currently at YELLOW.
EYJAFJALLAJÖKULL - (63o38' 00"N 019o37' 00"W), 1,666 m, ICELAND
As of the 5th of March, the the Department of Geophysics, University Of Iceland has reported that the Icelandic volcano Eyjafjallajökull has been very restless recently. The current seismicity and apparent inflation may be precursory to an eruption, or it may not - as Hugh Tuffen of Lancaster University observes, this kind of activity has been seen before, associated with dyke intrusion events (although the current seismicity is unusually energetic) and it is not possible at the moment to say whether this time it will end in an eruption: 'time will tell'. An interesting detail about the current activity comes from a source in Iceland who tells me that magma degassing under Eyjafjallajökull produced an 'acid pulse' that led to local water supplies become temporarily acidic about a month ago.
Eyjafjallajökull is an interesting volcano, not least because of its relationship with its near neighbour, Katla . This much larger volcano lies less than 30 km to the east of Eyjafjallajökull, beneath the Myrdalsjökull icecap. Katla is, the Global Volcanism Program reports, 'one of Iceland's most active [volcanoes] and is a frequent producer of damaging jökulhlaups, or glacier-outburst floods'. Katla, with more than twenty confirmed eruptions since the sixth century AD, has a much more active eruptive history than Eyjafjallajökull, which has just three eruptions over the same period. It seems, however, that there is a connection between these two closely-spaced volcanoes. Eyjafjallajökull's most recent eruption, December 1821 to January 1823, was followed by an eruption of Katla in June and July 1823. More recently an intrusion at Eyjafjallajökull in 1999 appears to have been followed by a small subglacial eruption in the Katla caldera.
It's intriguing that recent earthquake activity around Katla and Eyjafjallajökull has clustered in three areas: (1) shallow quakes around and within the Eyjafjallajökull caldera, (2) shallow quakes largely confined to the eastern part of Katla caldera, and (3) quakes with a deeper focus in the Godabunga area between the first two clusters. One possible interpretation of this pattern is that a cryptodome - an underground lava dome - is active beneath this area. The presence of viscous rhyolitic lava beneath Katla and Eyjafjallajökull makes for potentially explosive eruptive activity, if an eruption occurs.
An Icelandic commenter at Eruptions reports that the Iceland Meteorologial Office do not expect an eruption at Eyjafjallajökull. The volcano may get over its current bout of restlessness and calm down again, as happened with the intrusion events of 1994, 1999 and 2009. It clearly needs careful watching, however, as does its large and destructive neighbour, Katla.
Eyjafjöll (also known as Eyjafjallajökull) is located immediately west of Katla volcano. Eyjafjöll consists of an E-W-trending, elongated ice-covered basaltic-andesite stratovolcano with a 2.5-km-wide summit caldera. Fissure-fed lava flows occur on both the eastern and western flanks of the volcano, but are more prominent on the western side. Although the 1666-m-high volcano has erupted during historical time, it has been less active than other volcanoes of Iceland's eastern volcanic zone, and relatively few Holocene lava flows are known. The sole historical eruption of Eyjafjöll, during December 1821 to January 1823, produced intermediate-to-silicic tephra from the central caldera.
The colour code at Eyjafjallajökull is currently at YELLOW.
MAUNA LOA - (19o28' 30"N 151o36' 30"W), 4,170 m, HAWAII
As of the 3rd of March, the Hawaiian Volcano Observatory (HVO) has reported that Mauna Loa is not erupting. Monitor line lengths have remained steady across the summit and flanks of Mauna Loa, as measured by GPS receivers on opposite sides of the volcano, since mid-2009. Tiltmeters have recorded no significant changes other than abrupt offsets that are related to instrumental issues, severe weather, or significant earthquakes (the Chilean M8.8 earthquake on 2/26, for example). Sensors within a fissure in Moku`aweoweo crater floor reported gas concentrations and temperatures within normal value
Since the beginning of January, 2005, HVO analysts have rarely located more than 10 earthquakes per week beneath Mauna Loa summit and 1-5 earthquakes beneath the Kealakekua area of west Mauna Loa. The Kao`iki seismic zone between Mauna Loa and Kilauea volcano summits remained active with an average of about 10-40 earthquakes per week; these numbers may reflect increased seismic activity nearer Kilauea summit rather than increased Ka`oiki activity. In recent weeks, several magnitude 3+ earthquake have occurred beneath the Pahala area at the south end of the Kao`iki seismic zone.
The colour code at Mauna Loa is currently at YELLOW.
YELLOWSTONE CALDERA - (44o26'00"N 110o40'00"W), 2,805 m, UNITED STATES (Wyoming)
SPECIAL LINK REGARDING THE "SUPERVOLCANO" DOCUDRAMA ON YELLOWSTONE
As of the 3rd of March, the Yellowstone Volcano Observatory (YVO), reported that during the first half of February 2010, Yellowstone continued to experience a large swarm of earthquakes on the Madison Plateau, near the northwest margin of the Yellowstone Caldera. Retrospective analysis shows that the swarm began on January 15th, and picked up in intensity on the 17th of January. As of February 25th, a total of 1,809 earthquakes had been automatically located for the entire swarm, including 14 with a magnitude greater than 3.0; 136 with M2.0-2.9; 1,119 with M1.0-1.9; and 540 with M0.0-0.9. By the end of February 2010, earthquake activity at Yellowstone had returned to near-background levels.
Within the entire Yellowstone National Park region, 244 earthquakes received review by a seismologist during February. The largest event was a magnitude 3.1 on Feb. 2nd at 1931 hrs MST. This earthquake was part of the Madison Plateau swarm and was located 7 miles SSE of Madison Junction, WY. In addition a small earthquake swarm of 17 earthquakes occurred on February 13th, and was located about 12 miles NE of West Yellowstone, MT, with magnitudes ranging from -0.2 to 1.6. Some of the smallest events from the Madison Plateau swarm remain to be reviewed by a seismologist, and so the 244 earthquake tally is provisional.
Ground Deformation Summary: Continuous GPS data show that uplift of the Yellowstone Caldera has slowed significantly. Uplift rates for YVO GPS stations are less than 2.5 cm per year. The WLWY station, located in the northeastern part of the caldera, underwent a total of ~23 cm of uplift between mid-2004 and mid-2009.
The Yellowstone Plateau volcanic field developed through three volcanic cycles spanning two million years that included some of the world's largest known eruptions. Eruption of the >2450 cu km Huckleberry Ridge Tuff about 2.1 million years ago created the more than 75-km-long Island Park caldera. The second cycle concluded with the eruption of the Mesa Falls Tuff around 1.3 million years ago, forming the 16-km-wide Henrys Fork caldera at the western end of the first caldera. Activity subsequently shifted to the present Yellowstone Plateau and culminated 640,000 years ago with the eruption of the >1000 cu km Lava Creek Tuff and the formation of the present 45 x 85 km caldera. Resurgent doming subsequently occurred at both the NE and SW sides of the caldera and voluminous (1000 cu km) intracaldera rhyolitic lava flows were erupted between 150,000 and 70,000 years ago. No magmatic eruptions have occurred since the late Pleistocene, but large hydrothermal eruptions took place near Yellowstone Lake during the Holocene. Yellowstone is presently the site of one of the world's largest hydrothermal systems including Earth's largest concentration of geysers.
The colour code at Yellowstone is currently at GREEN.
