Sakurajima

Long, long ago, a gigantic eruption left a huge hole in the ground.

The sea filled the hole. Later, a new volcano grew there. That volcano is Sakurajima.

About 30,000 years ago, a colossal eruption left a giant crater called the Aira Caldera, Japan's Ministry of the Environment says. The Sakurajima Visitor Center puts that eruption at about 29,000 years ago and says seawater flowed in to make Kinko Bay.

A few thousand years later, Sakurajima erupted for the first time on the southern rim of the caldera and grew larger with each eruption. Its northern peak, Kitadake, is no longer active. The southern peak, Minamidake, became active about 4,500 years ago and still erupts today.

Ministry of the Environment (Kirishima-Kinkowan National Park text, 2018): about 30,000 years ago a colossal eruption's pyroclastic flow covered the area's mountains and valleys; the crater it left is the Aira Caldera; some 4,000 years later Sakurajima first erupted on the caldera's southern rim. Visitor Center: caldera eruption about 29,000 years ago, Sakurajima born in an undersea eruption about 3,000 years later.

The three peaks, Kitadake, Nakadake and Minamidake, were formed by two volcanoes: Kitadake, active until about 5,000 years ago, and Minamidake, active from about 4,500 years ago and erupting continuously since 1955 from two vents, Nakadake and Minamidake. Its magma originates beneath Kinkowan Bay.

Sakurajima used to be an island.

In 1914, lava flowed out and filled the sea between the island and the land. Now you can walk there!

The 'jima' in Sakurajima means 'island', the Ministry of the Environment explains. It really was an island until lava from the Taisho eruption of 1914 joined it to the Osumi Peninsula.

There have been 17 major eruptions since Sakurajima formed, and small eruptions happen almost every day. Five lava flows can be seen on the volcano today.

Ministry of the Environment: seventeen massive eruptions over the millennia, with smaller eruptions on an almost daily basis; the former island is attached to the mainland by a lava flow from the 1914 Taisho eruption (the Visitor Center: joined to the Osumi Peninsula). Five lava flows are visible; on the Arimura shore three can be seen: An'ei (1779), Taisho (1914) and Showa (1946).

Grasses grow near the top of the volcano. Pine trees grow lower down.

Old lava flows slowly turn green as plants move in.

Even close to the vents, Japanese pampas grass and Japanese knotweed grow. Farther down are shrubs such as Japanese eurya and Japanese green alder, and farther from the crater, Japanese black pine and Japanese bay trees.

On the Arimura shore you can compare three lava flows. Black pines grow among bare rock on the 1946 flow, the 1914 flow is greener, and forest grows on the oldest flow, from 1779.

Ministry of the Environment: pampas grass and Japanese knotweed grow around the summit nearest the vents; Japanese eurya and Japanese green alder lower down; Japanese black pine and Japanese bay trees farther from the crater. The Arimura flows show revegetation stages: hardy black pine among bare rock on the Showa (1946) flow, more verdant growth on the Taisho (1914) flow, thriving forest on the An'ei (1779) flow.

People have lived here since the Jomon period; the Visitor Center credits the fertile, ash-enriched soil and mild climate, and names Sakurajima Daikon and Sakurajima Komikan among its farm products.

Volcanic ash can be bad to breathe.

If ash falls, cover your nose and mouth and listen to the grown-ups in charge.

About 3,600 people live on Sakurajima, and the city of Kagoshima, with about 600,000 people, lies 4 kilometers across the sea. The Visitor Center shows live pictures of the crater, earthquake data and daily eruption counts.

The CDC says that near an active volcano you should follow the advice of local officials and be ready to leave or shelter. Volcanic ash can harm your lungs, so protect your breathing and eyes outdoors.

Visitor Center: about 3,600 residents; Kagoshima city (about 600,000 residents) 4 km across the sea, a 15-minute ferry ride; exhibits show live crater footage, seismic data and daily eruption statistics.

CDC volcano safety: follow local officials' advice; plan to evacuate or shelter; an emergency kit with respiratory protection and goggles; ash can harm the respiratory tract (an N95 respirator outdoors).