In News:

Sakurajima, one of the most active volcanoes of Japan, erupted multiple times recently, sending ash and smoke plumes up to 4.4 km into the atmosphere. The eruption led to ashfall-related disruptions, including cancellation of flights at Kagoshima Airport. This was the first eruption in nearly 13 months to send ash above 4 km.

Location & Geological Setting

• Located on the southern tip of Kyushu, near Kagoshima
• Lies at the southern edge of the Aira Caldera
• Situated on a convergent plate margin, associated with subduction-related volcanism

Type & Structure

• Stratovolcano: Built from alternating layers of lava and ash
• Andesitic volcano:
  • Magma is highly viscous
  • High gas content, making eruptions potentially explosive
• Composed mainly of two central cones:
  • Kitadake (north peak)
  • Minamidake (south peak)

Eruptive History

• Among the most active volcanoes in Japan, with frequent eruptions of varying intensity
• 1914 eruption:
  • One of Japan’s most powerful eruptions
  • Lava flows filled the strait, connecting Sakurajima island to the mainland peninsula
• 2019 eruption: Ash plume rose up to 5.5 km
• Recent eruptions monitored by the Japan Meteorological Agency, which also warned of ashfall in Kagoshima and nearby Miyazaki region

Associated Impacts

• Ashfall affecting aviation, transport and daily life
• Recurrent eruptions make Sakurajima a key site for volcanic hazard monitoring and disaster preparedness

What is a Volcano?

• A volcano is an opening in the Earth’s crust through which magma, gases and ash escape
• Eruptions may be:
  • Explosive (ash columns, pyroclasts)
  • Effusive (lava flows)
• Duration can range from days to years

In News:

Japan’s Sakurajima volcano, located in Kagoshima Prefecture on the southern island of Kyushu, recently erupted sending a dense ash plume 3,000 metres into the sky. The eruption originated from the Minamidake summit crater and was accompanied by a Level 3 volcanic alert, advising people to stay away from the vicinity.

Key Features of Sakurajima Volcano:

• Type: Stratovolcano (composite volcano)
• Geological Setting: Situated on a convergent plate boundary, formed from subduction-related volcanic activity.
• Structure: Comprises North Peak and South Peak, and lies on the southwestern rim of the Aira Caldera.
• Historical Significance: Was an island until the 1914 eruption, which connected it to the ?sumi Peninsula.
• Frequent Activity: One of Japan's most active volcanoes, experiencing daily minor eruptions and emitting continuous volcanic smoke.

Volcanic Characteristics:

• Lava Type:Andesitic – high in gas content and viscosity, leading to explosive eruptions.
• Hazards: Produces ash fall, pyroclastic flows, volcanic bombs, and toxic gases.
• Proximity to Populated Areas: Only 4 km from Kagoshima City, making it a high-risk volcano with strict monitoring by the Japan Meteorological Agency (JMA).

Impact and Preparedness:

• No injuries or major damages have been reported as of now.
• Ash fall warnings were issued for Kagoshima, Kumamoto, and Miyazaki prefectures.
• The eruption highlights Japan’s robust disaster preparedness and early warning systems, essential due to the country's location on the Pacific Ring of Fire.