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Large eruption of Tonga’s active undersea volcano Hunga Tonga-Hunga Haʻapai

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A large volcanic eruption is currently taking place at Hunga Tonga-Hunga Haʻapai undersea volcano near Tonga's capital Nuku'alofa. The volcano is indeed sending ash and steam high into the sky today, however, no official advisory was available at the press time.

The eruption was first reported by fisherman who came back from the area on December 19, according to the Deputy Secretary of Lands and Natural Resources, Taniela Kula, who filed a report to NEMO. 

Matangi Tonga Online said the eruption is clearly visible from the main island of Tongatapu today. It was photographed by Shane Egan from the Kanokupolu coastline… the plume of steam stood out clearly against today’s blue sky.

“It’s been puffing away like a steam train since Christmas Eve,” said Shane. “It’s Tonga’s own white Christmas.” He added the eruption was hard to see against the heavy clouds on the horizon before Christmas.

The last time this volcano erupted was in 2009. It appeared in GVP's weekly volcanic report during the week of March 18 – 24, 2009:

2009 eruption of Hunga Tonga-Hunga Ha'apai. Image credit: Tonga NEMO

"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."

False-color image showing the effects of the eruption of Hunga Tonga-Hunga Haʻapai volcano in Tonga, March 26, 2009. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite captured the image on March 25, 2009. The submerged vent has broken the surface of the Pacific Ocean and the new land is the dark mass south of Hunga Haʻapai. Clouds cover the space between the new land and Hunga Haʻapai. The vent itself is the nearly perfect circular hole near the southern edge of the new land. The ocean around the erupting volcano is bright blue, indicating ash, rock, and other volcanic debris. Plant-covered land is red. Note that Hunga Haʻapai is now colored black, indicating that plants on the island are now buried in ash or dead. NASA image created by Jesse Allen, using data provided courtesy of NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

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 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)

Featured image: Hunga Tonga-Hunga Haʻapai undersea volcano eruption 2009.

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