A volcano exploded Friday morning on sparsely populated Kuchinoerabu Island, sending smoke and ash soaring into the sky above Kagoshima Prefecture and residents fleeing to the safety of nearby Yakushima Island.

The 9:59 a.m. eruption of 626-meter Mount Shindake, the island’s main peak, produced a plume over 9 km high and a pyroclastic flow that reached the shoreline, the Meteorological Agency said.

There was no warning.

“I heard a loud boom and when I looked at the mountains, I saw a gigantic plume rising above,” said a 64-year-old innkeeper who was in her garden at the time.

“I thought I’d be dead if I got caught in the cloud,” she said explaining why she ran to the shelter without any belongings. “There was an eruption last year, but this time the sound was really loud.”

All 137 of Kuchinoerabu’s residents were confirmed safe, including a 72-year-old man who received a forehead burn but was able to walk unaided, the Fire and Disaster Management Agency and local authorities said.

All had been evacuated by ferry, coast guard ship and helicopter to neighboring Yakushima Island by Friday evening, the Yakushima town office said.

Both islands are about 100 km south of Kyushu, but Yakushima is usually reachable only by two ferry routes.

“I have instructed the relevant personnel to do all they can to ensure the safety of the islanders,” Prime Minister Shinzo Abe told reporters.

The prime minister’s office set up a response team at its crisis management center, while the Japan Coast Guard dispatched a large patrol ship to the area.

While no lava streams had been spotted as of Friday evening, a weather agency official warned of the risk of a second eruption and more pyro­clastic flows, noting that none had reached the more populous Maeda district.

Situated some 100 km off the southern tip of Kyushu, Kuchinoerabu has only about 100 full-time residents. Some believed to have been present at the time were short-term visitors. The prefectural government said 141 people in all, from 78 families, were ordered to evacuate.

The evacuation started after the weather agency raised its alert for the island to 5 — the highest level — from 3, which imposed limits on climbing the volcano.

Friday’s eruption, which unleashed a large ash cloud, created a panic as residents fled with only the barest necessities.

Yukina Masuda who managed to evacuate to a shelter near the top of another peak, Banyagamine, said the eruption was much bigger than last year’s.

“It looks like all of the island’s residents are crammed into this shelter,” she said.

Hiroshi Watanabe, 61, who manages a campsite on adjacent Yakushima, said he learned of the eruption via the local wireless system.

He said the gray fumes released by the volcano soon started spreading and streaming out volcanic ash that reached Yakushima.

“I’m worried about my friend who is a member of a volunteer fire corps on Kuchinoerabu Island,” he said.

Until Friday, the volcano’s most recent eruption had been on Aug. 3 last year. That eruption prompted 87 people, including some individuals visiting on business, to leave the following day.

Experts had recorded unusual activity for about a decade leading up to last year’s eruption, and the latest blast could be a relatively large, prolonged one, said associate professor Ryusuke Imura of Kagoshima University.

Meanwhile, the eruption on Sept. 27 last year of Mount Ontake became Japan’s worst postwar volcanic disaster, claiming dozens of lives near the summit. Fifty-seven people were confirmed dead, but six remain missing, presumed buried under ash and rock.

The hot-spring district of Mount Hakone near Tokyo has risen by up to 15 cm in two weeks this month as sulfurous steam gushes from vents in the mountain’s flank.

Mount Sakurajima, close to Kagoshima, erupted explosively in August 2013, unleashing a plume that was 5 km high. The same mountain had 178 small eruptions in March alone and produced one last week that created a plume 4.3 km high.

Nobuo Geshi of the National Institute of Advanced Industrial Science and Technology claims Friday’s eruption is the same type as the one seen at Sakurajima but much larger.

Geshi, who heads a group of scientists conducting research on massive eruptions, said it is very similar to the one the island experienced in 1966.

He said it can also be regarded as part of the volcanic activity that continued after the eruption last August.

Geshi pointed out that none of the past cases was a one-off eruption, suggesting the activity may continue for a while.

Kuchinoerabu, located in an area south of Kyushu with a large concentration of active volcanoes, has experienced numerous bouts of volcanic activity since Shindake’s colossal eruption in 1841, which scorched nearby villages and killed many residents.

According to the Meteorological Agency, in 1931 Shindake exploded on its western margin, causing landslides that killed two residents, animals and damaged farms and fields.

Several eruptions between December 1933 and January 1934 burned down a whole village. Eight people were killed and 26 were injured.

Shindake’s volcanic activities continued in the 1960s, resulting in another massive eruption in November 1966 that hurt three people and caused shock waves and pyroclastic flows that hit Kagoshima and Tanegashima Island, one of the Osumi Islands.

The mountain also experienced a small phreatic eruption in September 1980.

Since the 2000s, a large increase in volcanic quakes and tremors has been reported. An expansion at its crater and white fumes were detected in 2008, but one of its most recent eruptions, on Aug. 3, 2014, sent fumes higher than 800 meters.