The Origins of Sakurajima
Approximately 30,000 years ago, a colossal eruption buried Kagoshima in magma up to 60 meters deep. A pyroclastic flow of ash, stone, and gas covered the area’s mountains and valleys, rendering it flat in the space of a week. The volcanic crater cavity created by this epic eruption is the Aira Caldera.
Some 4,000 years later Sakurajima, located on the southern rim of the Aira Caldera, erupted for the first time, growing larger with each subsequent eruption. The northern peak, Kitadake, was active until 5,000 years ago. The southern peak, Minamidake, became active 4,500 years ago and is the peak that continues to erupt today.
Topography and Geology
Sakurajima, rising 1,117 meters above sea level, is the post-caldera volcano of the Aira Caldera. There are three peaks running north to south—Kitadake, Nakadake and Minamidake. The three peaks were formed by two volcanoes. The older volcano, Kitadake, is no longer active. The younger volcano, Minamidake, has been erupting continuously since 1955. It has two vents, Nakadake and Minamidake.
Sakurajima’s magma originates from beneath Kinkowan Bay. Over the millennia, there have been seventeen massive eruptions from Sakurajima, although smaller eruptions occur on an almost daily basis. The “jima” of “Sakurajima” means “island,” and although once separate it is now attached to the mainland as a result of a lava flow from the 1914 Taisho eruption.
Lava and Vegetation
Far from being bare, lifeless expanses of rock, volcanoes are home to a huge variety of vegetation. Around Sakurajima’s summit, closest to the volcanic vents, Japanese pampas grass and Japanese knotweed grow, while further down, Japanese eurya and Japanese green alder—deciduous evergreen shrubs—can be found. Further from the crater, Japanese black pine and Japanese bay trees thrive.
Lava flows are home to a diversity of vegetation, and because Sakurajima is home to five visible lava flows, it is possible to see the stages of revegetation up close. On the Arimura Seashore it is possible to see three flows, from the An’ei (1779), Taisho (1914), and Showa (1946) eruptions. The newest flow is characterized by hardy black pine growing among otherwise bare rock, while the Taisho flow boasts more verdant vegetation, and the oldest is now home to thriving forests.
Culture, Industry, Living
In addition to the residents of Sakurajima itself, the city of Kagoshima with a population 600,000 sits in the shadow of Sakurajima. The area's long history of human settlement suggests that volcano-side living has benefits that outweigh the dangers. Indeed, the volcano provides fertile soil for farming, ignimbrite rock for walling, and ash for a number of industries.
Activities
Unique activities abound, from classes on volcano-ash pottery and baking pizzas in lava rock ovens to nighttime eruption cruises. Add to those hiking, cycling, kayaking, hot springs, guided tours and more, and Sakurajima offers adventures to suit all tastes.
Dealing with Ash
Ash is a part of life for those living around Sakurajima. Far from seeing it as just a nuisance, residents have come up with ways to live with the ash and even profit from industries that make use of it. Street sweeper trucks keep the roads clean, while households bag ash that dusts their property. Weather forecasts include information on wind direction, allowing people to prepare appropriately. While some may choose to wear face masks when working outside, the ash doesn’t pose any health risks. Mostly, residents live their lives as normal, as have countless generations of inhabitants around Sakurajima.