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Posts Tagged ‘Hunga Tonga-Hunga Ha’apai’

Images of the Day: Tonga Islands Grow Larger

Posted by feww on March 28, 2009

New Landmass Formed by Hunga Tonga-Hunga Ha’apai Eruption

Submarine Eruption in the Tonga Islands


Image acquired March 26, 2009


Image acquired November 14, 2006

In mid-March 2009, a plume of ash and gas burst out of the ocean as an undersea volcano began to erupt in the South Pacific nation of Tonga. Small sections of the rim of the large undersea volcano had been above water, forming the islands of Hunga Tonga and Hunga Ha’apai. The eruption occurred at two vents, one submerged and the other on Hunga Ha’apai. The eruption pumped out enough rock and ash that by March 25, when the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA’s Terra satellite captured the top image, the submerged vent was surrounded by new land.

The new land is the dark mass south of Hunga Ha’apai. It had not been present when ASTER acquired the lower image on November 14, 2006. In the March 25 image, clouds cover the space between the new land and Hunga Ha’apai, but news reports indicate that the new land connects Hunga Ha’apai with the underwater vent, essentially enlarging the small island. The vent itself is the nearly perfect circular hole near the southern edge of the new land.

The image reveals some of the other impacts of the eruption. The ocean around the erupting volcano is bright blue, likely colored with ash, rock, and other volcanic debris. The eruption also killed or damaged plants on Hunga Ha’apai. In these false-color images, plant-covered land is red. In 2006, Hunga Ha’apai had supported vegetation, but after the eruption, the island was black. Either the plants were buried in ash or dead in the wake of the eruption. According to a visiting reporter, the eruption destroyed plant and birdlife on the island, leaving blackened tree stumps and dead birds and fish.

NASA image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team. Caption by Holli Riebeek.Instrument: Terra – ASTER

Related and Possibly Related Links:

Posted in ASTER, Terra satellite, undersea volcano, volcanic eruption, volcanism | Tagged: , , , , | Leave a Comment »

Weekly Volcano Watch: 26 March 2009

Posted by feww on March 26, 2009

Volcanic Activity Report: 18 March – 24 March 2009

Source: SI / USGS Weekly Volcanic Activity Report

New activity/unrest:

VoW: Fonualei, Tonga Islands (SW Pacific)

  • Country: Tonga
  • Subregion Name: Tonga Islands
  • Volcano Type: Stratovolcano
  • Volcano Status: Historical
  • Last Known Eruption: 1957
  • Summit Elevation: 180 m (591 feet)
  • Latitude: 18.02°S  (18°1’0″S)
  • Longitude: 174.325°W  (174°19’30″W)
  • Source: USGS


Fonualei:  Seen from the NE, Fonualei volcano has an upturned saucer profile. The small, less than 2-km-wide island of Fonualei contains a fumarolically active crater, which is breached to the SW with a fresh lava flow extending to the sea and forming a rugged shoreline. Blocky lava flows from a central pyroclastic cone have reached the sea through notches in the rim of a small caldera. Eruptions at Fonualei have been recorded since 1791, with the two largest taking place in October 1846 and July 1847. [In 1847,] explosive eruptions produced large pumice rafts, and ashfall damaged crops on the island of Vavua (56 km away) and fell on vessels up to 950 km distant. In 1939 explosive and effusive activity occurred from summit and flank vents, and water spouts were reported 1.6 km SE of the island. Photo by Paul Taylor (published in Taylor and Ewart, 1997). Caption: GVP

FEWW Comment: Fonualei may be one of the next volcanoes in the Tonga region to erupt in the next 30-90 days.

Ongoing Volcanic Activity:

The Weekly Volcanic Activity Report is a cooperative project between the Smithsonian’s Global Volcanism Program and the US Geological Survey’s Volcano Hazards Program.

Elevated Volcanic Activity in the US [Source: USGS]

Mar 25, 2009 at 21:08:47 PDT [PDT is 7 hours behind of Coordinated Universal Time,UTC]

The following U.S. volcanoes are known to be above normal background (elevated unrest or eruptions) or have shown activity that warranted an Information Release (for example, an earthquake swarm).

Volcano Alert Levels & Aviation Color Codes defined at http://volcanoes.usgs.gov/activity/alertsystem.

Volcano Hazards

Redoubt: Alert Level=WATCH. Aviation Color Code=ORANGE. As of Mar 25, 2009, 13:35 ADT

  • No explosions in last 36 hours and seismicity has declined. Possible lava dome growth at the summit. Explosions could resume without much warning.
    (Change to current status occurred on Mar 25, 2009 13:35 ADT from Alert Level WARNING and Aviation Color Code RED )For more information see http://www.avo.alaska.edu/activity/Redoubt.php

Kilauea: Alert Level=WATCH. Aviation Color Code=ORANGE. As of Mar 25, 2009, 07:53 HST

  • Elevated SO2 and some tephra from Halema`uma`u vent; elevated SO2 from Pu`u `O`o vent; lava in tubes to ocean. (Change to current status occurred on Jul 2, 2007 20:09 HST from Alert Level ADVISORY and Aviation Color Code YELLOW ). For more information see http://volcanoes.usgs.gov/hvo/activity/kilaueastatus.php

Cleveland: Alert Level=ADVISORY. Aviation Color Code=YELLOW. As of Mar 24, 2009, 12:46 ADT

Mauna Loa: Alert Level=ADVISORY. Aviation Color Code=YELLOW. As of Mar 2, 2009, 15:05 HST

Program Webcams page links to webcams at 19 of the 169 active volcanoes in the U-S.

Posted in ashfall, Chaiten, Fonualei, Kīlauea, volcanism | Tagged: , , , | Leave a Comment »

Weekly Volcano Watch: 19 March 2009

Posted by feww on March 19, 2009

Volcanic Activity Report: 11 March – 17 March 2009

Source: SI / USGS Weekly Volcanic Activity Report

New activity/unrest:

VoW: Hunga Tonga-Hunga Ha’apai, Tonga

Tonga Islands 20.57°S, 175.38°W; summit elev. 149 m – submarine volcano

An underwater volcanic eruption near the twin islands of Hunga Tonga and Hunga Ha’apai spewed a large column of  off-white smoke into the air. The plume rose to altitudes of about 8 km [possibly as high as 15km.]

tonga-ap
Hunga Ha’apai eruption [March 17-18, 2009] Aerial photo by Trevor Gregory/AP. Source. Image may be subject to copyright.

Observers flying near the area of Hunga Tonga-Hunga Ha’apai (about 62 km NNW of Nuku’alofa, the capital of Tonga) on 16 or 17 March reported seeing an eruption. Photos showed an eruption plume with a wide base that rose from the sea surface and mixed with meteorological clouds. Based on information from the Tonga airport and analysis of satellite imagery, the Wellington VAAC reported that on 18 March, a plume rose to altitudes of 4.6-7.6 km (15,000-25,000 ft) a.s.l. and drifted NE.

Geologic Summary. The small islands of Hunga Tonga and Hunga Ha’apai cap a large seamount located about 30 km SSE of Falcon Island. The two linear andesitic islands are about 2 km long and represent the western and northern remnants of a the rim of a largely submarine caldera lying east and south of the islands. Hunga Tonga and Hunga Ha’apai reach an elevation of only 149 m and 128 m above sea level, respectively, and display inward-facing sea cliffs with lava and tephra layers dipping gently away from the submarine caldera. A rocky shoal 3.2 km SE of Hunga Ha’apai and 3 km south of Hunga Tonga marks the most prominent historically active vent. Several submarine eruptions have occurred at Hunga Tonga-Hunga Ha’apai since the first historical eruption in 1912. GVP reported.


The small islands of Hunga Tonga and Hunga Ha’apai cap a large seamount located about 30 km SSE of Falcon Island. The two linear andesitic islands are about 2 km long and represent the western and northern remnants of a the rim of a largely submarine caldera lying east and south of the islands. Hunga Tonga and Hunga Ha’apai reach an elevation of only 149 m and 128 m above sea level, respectively, and display inward-facing sea cliffs with lava and tephra layers dipping gently away from the submarine caldera. A rocky shoal 3.2 km SE of Hunga Ha’apai and 3 km south of Hunga Tonga marks the most prominent historically active vent. Submarine eruptions were reported here in 1912 and 1937 and from a fissure 1 km SSE of Hunga Ha’apai in 1988. Aerial photo by Tonga Ministry of Lands, Survey, and Natural Resources, 1991 (published in Taylor and Ewart, 1997). Caption: GVP.


Hunga Tonga-Hunga Ha’apai volcano from space. Image captured by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite  on March 18, 2008. “In this image, the area around the eruption appears bright blue-green, likely resulting from sediment suspended in the water. The brilliant white patch at the center of the sediment-rich area may result from vapor released by the volcano. Northwest of the eruption site, a serpentine pumice raft floats on the water. The highly porous nature of pumice enables this volcanic rock to form floating rafts. (A larger pumice raft resulted from a similar eruption in the Tonga Islands in August 2006.).” Earth Observatory said.


A March 18 photo of Hunga Tonga-Hunga Ha’apai eruption as seen from the Nuku’alofa waterfront. Photo: AP/Matangi Tonga Online. Source. Image may be subject to copyright.

volcanoes-of-tonga
USGS Map of Major Volcanoes of Tonga with the approximate location of
Hunga Tonga-Hunga Ha’apai volcano marked.


Photo dated
Wednesday, March 18, 2009. Source: Xinhua/AFP. Image may be subject to copyright.

Video: Underwater volcano erupts off Tonga

Hunga Tonga-Hunga Ha’apai volcano

Flights were disrupted and airlines alerted after the undersea Hunga Tonga-Hunga Ha’apai volcano erupted.  Air New Zealand flights were forced to divert to  avoid  smoke, which reportedly rose to a height of about 15 km, various media reported.

The volcano located about 12km off the southwest coast off the main island of Tongatapu  is thought to have erupted on Monday. Hunga Tonga-Hunga Ha’apai is one of about 40 submarine volcanoes in the area.

It’s thought that the eruption does not pose an immediate threat to the residents because trade winds are blowing the smokes and  gases away from the island.

“It’s a very significant eruption, on quite a large scale.” Said Tonga’s Geological Service Chief, Keleti Mafi.

Rumble III

On March 13, the underwater volcano Rumble III,  located about 300km northeast of Bay of Plenty, New Zealand, was discovered to have undergone a “startling change” losing about 100m of its summit, with the 800m-wide crater completely missing, apparently in a catastrophic explosion.

Metis Shoal

On February 3, FEWW forecast that Metis Shoal, a submarine volcano located midway between the islands of Kao and Late (about 50 km NNE of Kao), was about to erupt, or was currently undergoing a period of unrest.

FEWW moderators believe that both  Metis Shoal, if indeed it has erupted / is erupting, and Hunga Tonga-Hunga Ha’apai volcanoes may have been triggered simultaneously.

FEWW List of Forgotten Volcanoes

Ongoing Volcanic Activity:

Elevated Volcanic Activity and Information Releases

Wednesday, Mar 18, 2009 at 17:47:50 PDT.

The following U.S. volcanoes are known to be above normal background (elevated unrest or eruptions) or have shown activity that warranted an Information Release (for example, an earthquake swarm).

Times are local to the volcano and in 24-hr format.
Volcano Alert Levels & Aviation Color Codes defined at http://volcanoes.usgs.gov/activity/alertsystem.

Volcano Hazards Program Webcams page links to webcams at 19 of the 169 active volcanoes in the U-S.

Related Links:

Posted in Chaiten, Galeras, Metis Shoal, Redoubt, Rumble III | Tagged: , , , , | 2 Comments »