Washington, Jan 18 (IANS): A volcanologist from the US Geological Survey (USGS) said that whether there would be more volcanic blasts or tsunami warnings for the country's West Coast after massive January 15 eruption off the coast of Tonga remained to be seen.

Wendy Stovall, volcanologist with the USGS Volcano Hazards Program (VHP), told the local media on Monday that the eruption was incredible and tsunami activity is actually harder to predict after an undersea volcano like this than say an earthquake, reports Xinhua news agency.

"There must have been a very large amount of magma that was exposed, somehow maybe from an underwater landslide or something, that then encountered the sea water and exploded really violently," she said.

"We will keep an eye out on things as it progresses, but certainly the type of volcano that it is there could be some additional eruptions that are large and could produce more tsunamis or it could just die out... We don't really know at this point," Stovall told KOIN news channel based in Oregon.

"There is evidence there that volcanism occurred through bodies of water that could send out big, nothing necessarily like what was experienced in Tonga, but could send out big pressure waves and similar stratospheric type of eruptions."

Stovall said that strong eruptions can sometimes cool the entire earth for a period of years, while noting that so far her colleagues studying data from Tonga have not calculated any numbers to suggest that that is the case here.

She said the volcano near Tonga is regularly active.

A smaller eruption started about December 20, 2021, but died out before this one set off tsunami warnings.