What is the Pacific ‘Ring of Fire’?

Q Why is it in News ?

A The Hunga Tonga-Hunga Ha’apai volcano which massively erupted lies along the Pacific ‘Ring of fire’, and is just over 60 kilometers from the island nation of Tonga.

Q What is the Pacific ‘Ring of Fire’?

A 

• The Pacific ‘Ring of Fire’ or Pacific rim, or the Circum-Pacific Belt, is an area along the Pacific Ocean that is characterized by active volcanoes and frequent earthquakes.
• Volcanic arcs and oceanic trenches partly encircling the Pacific Basin form the so-called Ring of Fire.
• It is home to about 75 per cent of the world’s volcanoes – more than 450 volcanoes.
• Also, about 90 per cent of the world’s earthquakes occur here.

Q How much is Its spread ?

A 

• Its length is over 40,000 kilometres and traces from New Zealand clockwise in an almost circular arc covering Tonga, Kermadec Islands, Indonesia.
• It is moving up to the Philippines, Japan, and stretching eastward to the Aleutian Islands, then southward along the western coast of North America and South America.

Q What is the extent of Seismic activity of the region ?

A 

• The area is along several tectonic plates including the Pacific plate, Philippine Plate, Juan de Fuca plate, Cocos plate, Nazca plate, and North American plate.
• The movement of these plates or tectonic activity makes the area witness abundant earthquakes and tsunamis every year.
• Along much of the Ring, tectonic plates move towards each other creating subduction zones.
• One plate gets pushed down or is subducted by the other plate.
• This is a very slow process – a movement of just one or two inches per year.
• As this subduction happens, rocks melt, become magma and move to Earth’s surface and cause volcanic activity.

Q What has happened in recent eruption in Tonga?

A 

• In the case of Tonga, the Pacific Plate was pushed down below the Indo-Australian Plate and Tonga plate, causing the molten rock to rise above and form the chain of volcanoes.
• Subduction zones are also where most of the violent earthquakes on the planet occur.
• The December 26, 2004 earthquake occurred along the subduction zone where the Indian Plate was subducted beneath the Burma plate.