A volcano is likely erupting deep beneath the Pacific Ocean, with ships told to avoid the area.
An eruption is believed to have happened in the US Commonwealth of the Northern Mariana Islands, although scientists are unable to confirm it due to the location’s inaccessibility.
All indications are that the Ahyi Seamount began erupting in mid-October, the US Geological Survey said on Monday.
The Northern Marianas are about 3,800 miles (6,115 km) west of Honolulu.
Scientists are looking to see if the activity is shallow earthquakes or if material exploded from the crater, said USGS research geophysicist Matt Haney.
Satellite observations show the water is discoloured, which suggests material is coming out of the volcano, he said.
“There’s nothing right now that suggests that this eruption will intensify and become a large eruption,” Mr Haney said.
Mariners should avoid the immediate area, he said.
Activity from an undersea volcanic source was picked up last month by hydroacoustic sensors some 1,400 miles away (2250 km) at Wake Island.
With help from the the Laboratoire de Geophysique in Tahiti and data from seismic stations in Guam and Japan, scientists analysed the signals to determine the source of the activity was likely Ahyi Seamount, the USGS said in a statement.
Activity has been declining in recent days, the statement said.
Ahyi Seamount is a large conical submarine volcano.
Its highest point is 259 feet (79 m) below the surface of the ocean and it is located about 11 miles (18 km) south-east of the island of Farallon de Pajaros, also known as Uracas.
“There are no local monitoring stations near Ahyi Seamount, which limits our ability to detect and characterise volcanic unrest there,” the agency said.
“We will continue to monitor available remote hydrophonic, seismic, and satellite data closely.”
The seamount is part of the Mariana Volcanic Arc, which is a chain of over 60 active volcanoes stretching over 600 miles west of and parallel to the Mariana Trench, the world’s deepest point.
It comes after a huge 7.5 magnitude earthquake struck the Pacific Ocean, forcing residents to seek higher ground amid a tsunami warning.
The tremor rocked the sea around 131 miles (210 kilometres) south-east of Tonga, with tsunami warnings have been issued for American Samoa, according to the Pacific Tsunami Warning Center (PTWC).
The quake struck 15 miles below the sea's surface in the Pacific Ocean, which prompted the initial tsunami warning for and neighbouring American Samoa.
Footage showed many evacuating to find high ground. Local government was advising people to move inland, while mariners were being urged to avoid reefs in the deep ocean.
