2009 Tonga earthquake
Encyclopedia
The 2009 Tonga earthquake was a 7.6 magnitude
earthquake
that occurred off the coast of Tonga
on March 19, 2009 UTC. It occurred at 18:17:41 UTC and had a depth of around 34 kilometres (21.1 mi). A tsunami
warning was not issued in the aftermath of the earthquake, and people got angry, although this was later cancelled. It was followed a short while later by an aftershock
earthquake that had a magnitude of 5.3. Two more aftershocks followed on March 20 (UTC), with magnitudes of 5.4 and 5.0 Mw, then another magnitude 5.0 aftershock on March 21, totalling four aftershocks above magnitude 5. The quake occurred approximately 220 kilometres (136.7 mi) to the southeast of Nuku'alofa
, the capital of Tonga, and initial reports suggest that there have been no injuries or significant damage. The earthquake was felt as far away as New Zealand
's North Island
, over 3000 kilometres (1,864.1 mi) away.
The earthquake occurred four days after the beginning of a major undersea volcanic eruption
near to Hunga Tonga
. As of yet there has been no confirmation of a direct link between the volcanic eruption and earthquake, but Ken Hudnut, a geophysicist for the United States Geological Survey
, stated that "it seems suggestive at this point". Keleti Mafi, the Tongan government's chief seismologist, has suggested that the earthquake is 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".
Moment magnitude scale
The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...
earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
that occurred off the coast of Tonga
Tonga
Tonga, officially the Kingdom of Tonga , is a state and an archipelago in the South Pacific Ocean, comprising 176 islands scattered over of ocean in the South Pacific...
on March 19, 2009 UTC. It occurred at 18:17:41 UTC and had a depth of around 34 kilometres (21.1 mi). A tsunami
Tsunami
A tsunami is a series of water waves caused by the displacement of a large volume of a body of water, typically an ocean or a large lake...
warning was not issued in the aftermath of the earthquake, and people got angry, although this was later cancelled. It was followed a short while later by an aftershock
Aftershock
An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...
earthquake that had a magnitude of 5.3. Two more aftershocks followed on March 20 (UTC), with magnitudes of 5.4 and 5.0 Mw, then another magnitude 5.0 aftershock on March 21, totalling four aftershocks above magnitude 5. The quake occurred approximately 220 kilometres (136.7 mi) to the southeast of Nuku'alofa
Nuku'alofa
Nukualofa is the capital of the Kingdom of Tonga. It is located on the north coast of the island of Tongatapu, in the southern most island group of Tonga.-Mythological origins:...
, the capital of Tonga, and initial reports suggest that there have been no injuries or significant damage. The earthquake was felt as far away as New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
's North Island
North Island
The North Island is one of the two main islands of New Zealand, separated from the much less populous South Island by Cook Strait. The island is in area, making it the world's 14th-largest island...
, over 3000 kilometres (1,864.1 mi) away.
The earthquake occurred four days after the beginning of a major undersea volcanic eruption
2009 Tonga undersea volcanic eruption
The 2009 Tonga undersea volcanic eruption refers to ongoing volcanic activity that began on March 16, 2009, near the island of Hunga Tonga, approximately from the Tongan capital of Tongatapu. The volcano is in a highly active volcanic region that represents a portion of the Pacific Ring of Fire...
near to Hunga Tonga
Hunga Tonga
Hunga Tonga-Hunga Haapai is a volcano located about 30 km south-southeast of Fonuafoou , part of Tonga.The volcano is part of the highly active Tonga-Kermadec Islands volcanic arc, a subduction zone extending from New Zealand north-northeast to Fiji. The volcano lies about above a very active...
. As of yet there has been no confirmation of a direct link between the volcanic eruption and earthquake, but Ken Hudnut, a geophysicist for the United States Geological Survey
United States Geological Survey
The United States 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, and the natural hazards that threaten it. The organization has four major science disciplines, concerning biology,...
, stated that "it seems suggestive at this point". Keleti Mafi, the Tongan government's chief seismologist, has suggested that the earthquake is 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
Magma
Magma is a mixture of molten rock, volatiles and solids that is found beneath the surface of the Earth, and is expected to exist on other terrestrial planets. Besides molten rock, magma may also contain suspended crystals and dissolved gas and sometimes also gas bubbles. Magma often collects in...
to be ejected".
See also
- 2009 Tonga undersea volcanic eruption2009 Tonga undersea volcanic eruptionThe 2009 Tonga undersea volcanic eruption refers to ongoing volcanic activity that began on March 16, 2009, near the island of Hunga Tonga, approximately from the Tongan capital of Tongatapu. The volcano is in a highly active volcanic region that represents a portion of the Pacific Ring of Fire...
- Hunga TongaHunga TongaHunga Tonga-Hunga Haapai is a volcano located about 30 km south-southeast of Fonuafoou , part of Tonga.The volcano is part of the highly active Tonga-Kermadec Islands volcanic arc, a subduction zone extending from New Zealand north-northeast to Fiji. The volcano lies about above a very active...
- 2006 Tonga earthquake2006 Tonga earthquakeThe 2006 Tonga earthquake occurred on 4 May 2006 at 04:26 local time . There were no reports of death or injury. With a strength of 7.9 it was the strongest quake since the 28 March 2005 Sumatra earthquake following from the infamous 2004 Indian Ocean earthquake .-Summary:The United States...
- 2007 Tonga earthquake2007 Tonga earthquakeThe 2007 Tonga earthquake occurred on 9 December 2007 at 20:28:24 local time . NOAA rated a strength of 7.9 on the Richter scale, and USGS at 7.6. There were no reports of damage, death or injury....