Based on information from Tonga Meteorological Services, analysis of satellite imagery, and pilot observations, the Wellington VAAC reported that during 18-19 March ash plumes from Hunga Tonga-Hunga Ha'apai rose to altitudes of 4-5.2 km (13,000-17,000 ft) a.s.l. and drifted NE and about 480 km ENE. On 20 March, steam plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. Wide-spread haze was reported in areas downwind, below an altitude of 1.5 km (5,000 ft) a.s.l., including in Vava'u, a group of islands about 255 km NE of Hunga Tonga-Hunga Ha'apai. On 21 March, an eruption plume rose to an altitude of 0.8 km (2,500 ft) a.s.l.

According to news articles, the eruption started on 16 March from two vents, one on Hunga Ha'apai and another about 100 m offshore. Video footage and photographs taken from a nearby boat and posted on 20 March showed repeated dark, ash-rich Surtseyan explosions and associated base surges from two vents. A journalist that visited the area reported that the island was covered with black ash, and coconut trees were reduced to black stumps. Dead birds and fish were seen in the water.

18 March 2009            Back to Top

Based on information from Tonga Meteorological Services, analysis of satellite imagery, and pilot observations, the Wellington VAAC reported that during 18-19 March ash plumes from Hunga Tonga-Hunga Ha'apai rose to altitudes of 4-5.2 km (13,000-17,000 ft) a.s.l. and drifted NE and about 480 km ENE. On 20 March, steam plumes rose to an altitude of 1.8 km (6,000 ft) a.s.l. Wide-spread haze was reported in areas downwind, below an altitude of 1.5 km (5,000 ft) a.s.l., including in Vava'u, a group of islands about 255 km NE of Hunga Tonga-Hunga Ha'apai. On 21 March, an eruption plume rose to an altitude of 0.8 km (2,500 ft) a.s.l.

According to news articles, the eruption started on 16 March from two vents, one on Hunga Ha'apai and another about 100 m offshore. Video footage and photographs taken from a nearby boat and posted on 20 March showed repeated dark, ash-rich Surtseyan explosions and associated base surges from two vents. A journalist that visited the area reported that the island was covered with black ash, and coconut trees were reduced to black stumps. Dead birds and fish were seen in the water.

Sources: Agence France-Presse (AFP) , Wellington Volcanic Ash Advisory Center (VAAC) , Infobae

11 March 2009            Back to Top

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.

Sources: Steven Gates and Keizo Gates , Wellington Volcanic Ash Advisory Center (VAAC)

Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Bryan W B, Stice G D, Ewart A, 1972. Geology, petrology, and geochemistry of the volcanic islands of Tonga. {J Geophys Res}, 77: 1566-1585

Ewart A, Brothers R N, Mateen A, 1977. An outline of the geology and geochemistry, and the possible petrogenetic evolution of the volcanic rocks of the Tonga-Kermadec-New Zealand island arc. {J Volc Geotherm Res}, 2: 205-250

Ewart A, Bryan W B, Gill J B, 1973. Mineralogy and geochemistry of the younger volcanic islands of Tonga, southwest Pacific. {J Petr}, 14: 429-465

Richard J J, 1962. Kermadec, Tonga and Samoa. {Catalog of Active Volcanoes of the World and Solfatara Fields}, Rome: IAVCEI, 13: 1-38

Taylor P W, 1999. . (pers. comm.)

Taylor P W, Ewart A, 1997. The Tofua Volcanic Arc, Tonga, SW Pacific: a review of historic volcanic activity. {Aust Volc Invest Occ Rpt}, 97/01: 1-58

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 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.