The 2009 Tonga undersea volcanic eruption began on 16 March 2009, near the island of Hunga Tonga, approximately from the

Tonga Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in ...

n capital of

Nukuʻalofa Nukualofa (; ) is the capital and largest city of Tonga. It is located on the north coast of the island of Tongatapu, in the country's southernmost island group. History First western records of Nukualofa On 10 June 1777, British captain Jam ...

. The volcano is in a highly active volcanic region that represents a portion of the

Pacific Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring o ...

. It is estimated that there are up to 36 undersea volcanoes clustered together in the area.

Eruption history

The initial 16–17 March

eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...

created an ejecta column (

tephra Tephra is fragmental material produced by a volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they re ...

) which sent ash and

smoke Smoke is a suspension of airborne particulates and gases emitted when a material undergoes combustion or pyrolysis, together with the quantity of air that is entrained or otherwise mixed into the mass. It is commonly an unwanted by-produc ...

up to into the atmosphere and an initial inspection reported that the volcano had breached the ocean surface. 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. Between 18–20 March, a number of

Surtseyan eruption A Surtseyan eruption is an explosive style of volcanic eruption that takes place in shallow seas or lakes when rapidly rising and fragmenting hot magma interacts explosively with water and with water-steam-tephra slurries. The eruption style is ...

s sent ash plumes as high as to into the atmosphere, with prevailing winds pushing the ash cloud about east-northeast of the eruption site and widespread and significant haze reported at Vavau away. Steam plumes on 20 March were measured at above sea level. But on 21 March, an eruption sent steam and ash just into the sky. On 21 March, Tonga's chief geologist Kelepi Mafi reported lava and ash from two vents, one on the uninhabited island Hunga Haapai and another about offshore, had filled the gap between the two vents, creating new land surface that measured hundreds of square metres."'No Living Thing Left' As Tonga Volcano Erupts."
'' Agence France-Presse.'' 20 March 2009. The eruption devastated Hunga Haapai, covering it in black ash and stripping it of vegetation and fauna.

Disruptions

Two

Air New Zealand Air New Zealand Limited () is the flag carrier airline of New Zealand. Based in Auckland, the airline operates scheduled passenger flights to 20 domestic and 30 international destinations in 18 countries, primarily around and within the Pacif ...

airline flights into Tonga were delayed due to safety concerns caused by the volcanic ash, but flight schedules returned to normal shortly thereafter. Tongan officials also expressed concern that the eruption could significantly harm the country's fishing industry."Tonga Examines Volcano's Fishing Impact." ''Radio Australia News.'' March 23, 2009.

2009 Tonga earthquake

Four days after the start of the eruption a strong

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

measuring 7.6 also struck the region. Ken Hudnut, a geophysicist for the

United States Geological Survey The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

, stated that "The association with the

volcanic activity Volcanism, vulcanism or volcanicity is the phenomenon of eruption of molten rock (magma) onto the surface of the Earth or a solid-surface planet or moon, where lava, pyroclastics, and volcanic gases erupt through a break in the surface called a ...

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.". Keleti Mafi, the Tongan government's chief seismologist, also suggested that the earthquake was likely to have a direct impact on the

volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are oft ...

, stating that the "strength of the earthquake could crack the volcano's (undersea) vent and allow more

magma Magma () is the molten or semi-molten natural material from which all igneous rocks are formed. Magma is found beneath the surface of the Earth, and evidence of magmatism has also been discovered on other terrestrial planets and some natural sa ...

to be ejected".

Notes

References

External links

Footage of the eruption, BBC website
* {{DEFAULTSORT:Tonga Undersea Volcanic Eruption, 2009 Submarine eruptions Surtseyan eruptions

Volcano A volcano is a rupture in the Crust (geology), crust of a Planet#Planetary-mass objects, planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and volcanic gas, gases to escape from a magma chamber below the surface. On Ear ...

Volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are oft ...

2009 natural disasters Tonga undersea volcanic eruption March 2009 events in Oceania