2009 Tonga undersea volcanic eruption

Volcanic eruption creating a new land linking Hunga Tonga and Hunga Haʻapai islands

2009 Tonga undersea volcanic eruption

False-color satellite image taken 25 March 2009, showing new land south of Hunga Haʻapai. Clouds cover the space between the new land and Hunga Haʻapai. The vent is the nearly perfect circular hole near the southern edge of the new land.

Volcano| Hunga Tonga–Hunga Ha'apai
Start date| 16 March 2009[1][a]
End date| 22 March 2009[1]
Type| Submarine, Surtseyan
Location| Tonga
20°34′S 175°23′W﻿ / ﻿20.57°S 175.38°W﻿ / -20.57; -175.38
VEI| 2[1]

The 2009 Tonga undersea volcanic eruption began on 16 March 2009,[5] near the island of Hunga Tonga, approximately 62 kilometres (39 mi) from the Tongan capital of Nukuʻalofa.[6] The volcano is in a highly active volcanic region that represents a portion of the Pacific Ring of Fire. It is estimated that there are up to 36 undersea volcanoes clustered together in the area.[7]

## Eruption history

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The initial 16–17 March eruption created an ejecta column (tephra) which sent ash and smoke up to 20 kilometres (12 mi) into the atmosphere and an initial inspection reported that the volcano had breached the ocean surface.[8][9] Authorities suggested at that time that the eruption did not yet pose any threat to the capital's population, and an inspection team was sent out to evaluate the volcano.[10]

Between 18 and 20 March, a number of Surtseyan eruptions sent ash plumes as high as 4 kilometres (2.5 mi) to 5.2 kilometres (3.2 mi) into the atmosphere, with prevailing winds pushing the ash cloud about 480 kilometres (300 mi) east-northeast of the eruption site and widespread and significant haze reported at Vavaʻu 255 kilometres (158 mi) away.[11] Steam plumes on 20 March were measured at 1.8 kilometres (1.1 mi) above sea level.[11] But on 21 March, an eruption sent steam and ash just 0.8 kilometres (0.50 mi) into the sky.[11] On 21 March, Tonga's chief geologist Kelepi Mafi reported lava and ash from two vents, one on the uninhabited island Hunga Haʻapai and another about 100 m (330 ft) offshore, had filled the gap between the two vents, creating new land surface that measured hundreds of square metres.[12][13] The eruption devastated Hunga Haʻapai, covering it in black ash and stripping it of vegetation and fauna.[13]

## Disruptions

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Two Air New Zealand airline flights into Tonga were delayed due to safety concerns caused by the volcanic ash, but flight schedules returned to normal shortly thereafter.[14]

Tongan officials also expressed concern that the eruption could significantly harm the country's fishing industry.[15]

## 2009 Tonga earthquake

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Four days after the start of the eruption a strong earthquake measuring 7.6 Mw(ISC) also struck the region. Ken Hudnut, a geophysicist for the United States Geological Survey, stated that "The association with the volcanic activity seems to be an interesting added dimension to this. It's not clear at this point that there is a direct association, but it seems suggestive at this point.".[6] Keleti Mafi, the Tongan government's chief seismologist, also suggested that the earthquake was likely to have a direct impact on the volcanic eruption, stating that the "strength of the earthquake could crack the volcano's (undersea) vent and allow more magma to be ejected".[8]

## See also

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* Oceania portal
* Volcanoes portal

* 2022 Hunga Tonga–Hunga Haʻapai eruption and tsunami
* Tonga Trench – deepest trench in the Southern hemisphere where the Pacific plate is being subducted westward

## Notes

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1. ^ The date the eruption began is uncertain. According to the Smithsonian Institution's Global Volcanism program, "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."[2] The report cites Keizo Gates' web log, dated 16 March 2009, which contains photos allegedly taken from civilian aircraft late on the afternoon of March 16.[3] The Smithsonian subsequently confirmed that the eruption began on 16 March.[4]

## References

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1. ^ a b c "Hunga Tonga-Hunga Ha'apai: Eruptive History". Global Volcanism Program. Smithsonian Institution. Retrieved 2 February 2022.
2. ^ SI/USGS Weekly Volcanic Activity Report 11–17 March 2009 (Report). Smithsonian Institution / USGS. Archived from the original on 13 April 2009.
3. ^ Gates, Keizo (16 March 2009). "New Tonga eruption". Kzo.net. Archived from the original on 22 April 2016.
4. ^ SI/USGS Weekly Volcanic Activity Report 18–24 March 2009 (Report). Smithsonian Institution / USGS. Archived from the original on 2 March 2021.
5. ^ The date the eruption began was initially uncertain. According to the Smithsonian Institution's Global Volcanism program, "Observers flying near the area of Hunga Tonga-Hunga Ha'apai (about 62 km NNW of Nukuʻalofa, the capital of Tonga) on 16 or 17 March reported seeing an eruption." See: SI/USGS Weekly Volcanic Activity Report. 11 March-17 March 2009. Archived 13 April 2009 at the Wayback Machine The report cites Keizo Gates' Web log, dated 16 March 2009, which contains photos allegedly taken from civilian aircraft late on the afternoon of 16 March. See: Gates, Keizo. "New Tonga Eruption" Kzo.net. March 16, 2009. Archived 22 April 2016 at the Wayback Machine The Smithsonian subsequently confirmed that the eruption began on 16 March. See: SI/USGS Weekly Volcanic Activity Report. 18 March-24 March 2009. Archived 25 April 2009 at the Wayback Machine
6. ^ a b "Major quake strikes off Tonga". CNN. 19 March 2008. Archived from the original on 22 March 2009. Retrieved 19 March 2009.
7. ^ "Undersea Volcano Erupts Off Tonga Coast". Fox News. 18 March 2009. Archived from the original on 6 August 2009. Retrieved 20 March 2009.
8. ^ a b "Strong quake near Tonga prompts tsunami warning". Yahoo News. 20 March 2009. Archived from the original on 23 March 2009. Retrieved 21 March 2009.
9. ^ Barrowclough, Anne (20 March 2009). "Underwater volcano sends huge columns of ash into Pacific sky". The Times. London. Archived from the original on 16 January 2022. Retrieved 20 March 2009.
10. ^ "Tongan inspection team heads to undersea volcano". Yahoo News. 19 March 2009. Archived from the original on 22 March 2009. Retrieved 20 March 2009.
11. ^ a b c "SI/USGS Weekly Volcanic Activity Report. 18 March-24 March 2009". Archived from the original on 2 March 2021. Retrieved 23 March 2009.
12. ^ Percival, Jenny. "Underwater Volcano Creates New Island Off Tonga." Archived 8 December 2016 at the Wayback Machine The Guardian. 21 March 2009.
13. ^ a b "'No Living Thing Left' As Tonga Volcano Erupts." Archived 6 July 2012 at the Wayback Machine Agence France-Presse. 20 March 2009.
14. ^ "Night Flights Postponed As Volcanic Activity Continues." Matangi Tonga. March 23, 2009 Archived 27 May 2011 at the Wayback Machine; "Flights Back to Normal But Tongan Volcanoes Still Erupting." Radio New Zealand International. March 24, 2009. Archived 4 April 2012 at the Wayback Machine
15. ^ "Tonga Examines Volcano's Fishing Impact." Radio Australia News. March 23, 2009.[usurped]

## External links

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* Footage of the eruption, BBC website
* "The Big Picture – Undersea eruptions near Tonga". The Boston Globe. 19 March 2009. Archived from the original on 22 March 2009. Retrieved 22 March 2009.