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Sonic boom, earthquake, tsunami waves: Why Tonga’s volcanic eruption was no easy feat | world news

The eruption of the Hunga Tonga Hunga Ha’apai volcano in the southern Pacific island of Tonga was no small feat. It triggered tsunami waves in the Pacific and choked Tonga in dust.

Watch: “Stay away from the coast…”, a volcanic eruption triggers panic

Saturday’s eruption was so powerful it was recorded around the world and sent pressure shockwaves around the planet twice.

As more and more details emerge about the natural incident, here’s a look at what a volcanic eruption is and the global impact of what happened in Tonga.

What is a volcanic eruption?

Before talking about volcanic eruptions, it is important to understand what a volcano is. A volcano is an opening or break in the earth’s surface that allows magma – which comes out as liquid and semi-liquid hot rock – ash and volcanic gases to escape.

Volcanic hotspots are places that occur where the Earth’s tectonic plates come together.

A volcanic eruption occurs when lava and gas are released from a volcano – sometimes explosively.

Underwater volcanic eruption

This type of eruption occurs in a volcano located below the surface of the ocean. There are about a million submarine volcanoes, and most of them are located near tectonic plates.

Besides lava, these openings also spit ash. These settle on the ocean floor and lead to the formation of sea mounds – underwater mountains that form on the ocean floor but do not reach the surface of the water.

How many active volcanoes are there on Earth?

According to the USGS, there are about 1,350 potentially active volcanoes around the world. About 500 of them have erupted, according to data available from the USGS. Many of them are located along the Pacific Rim in what is known as the “Ring of Fire”.

Impact of volcanic eruption on Earth’s climate

Huge volcanic eruptions can sometimes cause temporary global cooling as sulfur dioxide is pumped into the stratosphere. But in the case of the Tonga eruption, early satellite measurements indicated that the amount of sulfur dioxide released would have only a minimal global average cooling effect of perhaps 0.01 Celsius (0.02 Fahrenheit), said Alan Robock, a professor at Rutgers University.

What happened in Tonga?

Satellite images showed the spectacular underwater eruption on Saturday evening, with a plume of ash, steam and gas rising like a giant mushroom above the waters of the South Pacific.

A sonic boom was heard as far away as Alaska.

Some climate experts said the eruption changed atmospheric pressure, which may have briefly helped clear fog in Seattle, United States.

Tsunami waves of about 80 centimeters (2.7 feet) crashed into Tonga’s coastline, and New Zealand Prime Minister Jacinda Ardern described damage to boats and shops on Tonga’s coastline.

The waves crossed the Pacific, drowning two people in Peru and causing minor damage from New Zealand to Santa Cruz, California.

The US Geological Survey estimated that the eruption caused the equivalent of a magnitude 5.8 earthquake.