Underwater Volcano Spews Smoke and Ash Off Japan

An underwater volcano erupted Thursday off central Japan, spewing plumes of smoke and ash into the air and creating tremors that shook the Izu Peninsula.

There were no reports of injuries or damage, but callers jammed telephone lines for hours after the eruption a mile off the coast at Ito, a seaside resort 62 miles southwest of Tokyo.

Hundreds of Ito’s 72,000 residents fled, and city officials were considering evacuating people living near the shore, according to the Japan Broadcasting Corp. The Central Meteorological Agency issued a navigation warning to ships in the area.

The volcano erupted at 6:30 p.m. on the ocean floor at a depth of several thousand feet, the meteorological agency said.

“Right now, we don’t know if this will lead to another, larger eruption and can only tell people there to watch for further warnings,” said an agency official. “Obviously, there could be danger to Ito if a larger eruption occurs,” he said, requesting anonymity.

The Japanese archipelago is of volcanic origin, and 80 volcanoes are believed to be active.

For hours after the eruption, calls to Ito police and City Hall were met with recorded messages asking callers to try later because of “extremely crowded lines.”

Along with the strong jolt of the eruption, slight tremors, possibly caused by the volcano, were felt throughout the evening, said the official from the meteorological agency.

Seismologists were surveying movements of underground magma in the area. Large movements of magma can cause earthquakes, which often preceed volcanic eruptions.

More than 20,000 earthquakes have been recorded around Izu over the past two weeks.

An official of the Seismic Division of the Central Meteorological Agency, who spoke on condition of anonymity, said the nature of the quakes had changed since Tuesday night, with the most recent quakes occurring more frequently and lasting up to 20 seconds.

Between June 30 and noon Thursday, 22,328 temblors were recorded off the Izu Peninsula, the meteorological agency said. Most were at depths of two to 4.5 miles under the sea.

Twenty-one people suffered minor injuries when two earthquakes registering a magnitude of 5.5 struck Ito on Sunday.