Miyakejima is an island stratovolcano located in Japan at latitude 34.094°N, longitude 139.526°E, with a summit elevation of 775 meters above sea level. Positioned in a subduction zone setting with oceanic crust less than 15 kilometers thick, the volcano is cataloged under Global Volcanism Program volcano number 284040. According to official historical and geological records, Miyakejima has a documented history of 39 confirmed eruptions dating from 6450 BCE through 2010 CE.
Eruptive History and Volcanic Explosivity Index (VEI)
The Volcanic Explosivity Index (VEI) measures eruption magnitude based on factors such as ejected material volume and eruption cloud height. VEI values have been assigned for 38 of Miyakejima's 39 confirmed eruptions. The largest recorded magnitude reached by the volcano is VEI 4.
Geological tephrochronology establishes the earliest recorded eruption around 6450 BCE (±500 years) on the northwest flank, reaching VEI 4. Earlier centuries rely primarily on physical deposits, whereas activity in the second millennium CE is increasingly documented through written observations. Eruption locations have varied across the volcano over time, taking place at the summit crater, flank zones, and coastal areas.
Distribution of Recorded Eruptions by Century
Miyakejima's 39 confirmed eruptions are distributed across the following centuries:
- 65th century BCE: 1 eruption
- 29th century BCE: 1 eruption
- 20th century BCE: 1 eruption
- 18th century BCE: 1 eruption
- 15th century BCE: 1 eruption
- 13th century BCE: 1 eruption
- 10th century BCE: 1 eruption
- 6th century BCE: 1 eruption
- 1st century BCE: 1 eruption
- 3rd century CE: 1 eruption
- 4th century CE: 1 eruption
- 5th century CE: 1 eruption
- 8th century CE: 1 eruption
- 9th century CE: 2 eruptions
- 11th century CE: 1 eruption
- 12th century CE: 1 eruption
- 15th century CE: 1 eruption
- 16th century CE: 2 eruptions
- 17th century CE: 1 eruption
- 18th century CE: 2 eruptions
- 19th century CE: 3 eruptions
- 20th century CE: 4 eruptions
- 21st century CE: 9 eruptions
Representative Eruption Records
Detailed event entries in the official record highlight activity across different areas of the volcano:
- 6450 BCE (±500 years): A VEI 4 eruption on the northwest flank, established through tephrochronology.
- 320 CE (±500 years): A VEI 3 eruption in the Sabigahama area, dated by tephrochronology.
- November 22, 1595: A VEI 2 eruption on the southeast flank, confirmed by reported observations.
- August 17, 1763 – 1769: A VEI 4 eruption involving Oyama on the south-southwest flank (Shinmio maar), recorded via reported observations.
- April 10, 2010 – July 21, 2010: A VEI 1 eruption at the summit crater, confirmed through direct observations.
The summit eruption that ended on July 21, 2010, marks the latest completed eruption in the official structured record.
Frequently asked questions
How many confirmed eruptions are on record for Miyakejima?
Miyakejima has 39 confirmed eruptions recorded in the official Smithsonian Global Volcanism Program database, spanning from 6450 BCE to 2010 CE.
What is the highest VEI magnitude recorded at Miyakejima?
The highest magnitude recorded at Miyakejima is VEI 4, which occurred during eruptions such as the prehistoric event around 6450 BCE and the historical eruption from 1763 to 1769 CE.
When was the most recent confirmed eruption at Miyakejima?
The most recent confirmed eruption started on April 10, 2010, and concluded on July 21, 2010, at the summit crater.
Sources and further context
Official datasets support the event-specific facts.