Around the planet, a powerful undersea volcanic eruption was felt.

Scientists reported Sunday that the big underwater volcanic eruption in Tonga was so powerful that it was recorded all over the world and caused a tsunami that flooded Pacific coasts from Japan to the United States. 

The protracted, rumbling eruption of the Hunga Tonga-Hunga Ha'apai volcano spews smoke and ash into the air, with a deafening rumble recorded 10,000 kilometres (6,000 miles) away in Alaska, according to dramatic satellite photographs.

Saturday's explosion was equivalent to a 5.8 magnitude earthquake at zero depth, according to the US Geological Survey. 

The impact of the eruption was "quite moderate," according to Marco Brenna, a senior lecturer at Otago University's School of Geology, but another eruption with a considerably larger impact could not be ruled out.

Waves of roughly 1.2 metres slammed against Japan's Pacific coast, with the Japan Meteorological Agency predicting waves of up to three metres. 

When a big wave slammed into a marina in New Zealand, more than 2,300 kilometres from Tonga, 120 people were evacuated from northern coastal areas and several boats were wrecked.

The famed Bondi Beach in Sydney, Australia, was momentarily evacuated as a precaution, while coastal streets in Santa Cruz, California, were flooded and blocked to traffic. 

The Alaska Volcano Observatory detected the eruption "6,000 miles from the volcano" in Anchorage and Fairbanks, according to the National Weather Service Alaska.

After the explosions caused a spike in its air pressure graph, the Fife weather station in Scotland tweeted that it was "simply astounding to think of the power that can send a shockwave around the world." 

Hunga-Tonga-Hunga-Ha'apai, about 65 kilometres north of Nuku'alofa, has a turbulent past. 

During a 2009 eruption, it exceeded sea level, and in 2015, it shot so many big rocks and ash into the air that when they settled, a new island 2 kilometres long, 1 kilometre wide, and 100 metres high was formed.