Photo: US Geological Survey
An underwater volcano is likely erupting deep beneath the Pacific Ocean in the Northern Mariana Islands, but scientists don't know for sure because of its remoteness.
The US Geological Survey said all indications were that the Ahyi Seamount began erupting in mid-October.
Matt Haney, a research geophysicist with the agency, said scientists were looking to see if the activity was caused by shallow earthquakes, or if material had exploded from the crater.
He said satellite observations showed the water was discoloured, which suggested material was coming out of the volcano.
"There's nothing right now that suggests that this eruption will intensify and become a large eruption," Haney said.
But he warned mariners would still want to avoid the immediate area.
Activity from an undersea volcanic source was picked up last month by hydroacoustic sensors some 2250km away at Wake Island in Micronesia.
Ahyi seamount is a large conical submarine volcano. Its highest point is 79 metres below the surface of the ocean. It is located about 18km 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 (965km) west of and parallel to the Mariana Trench, the world's deepest point.
