Tokachidake (Japan): Recorded Eruptions and Historical Activity

Tokachidake is a stratovolcano complex standing 2,077 meters high in Japan, situated within a subduction zone and continental crust tectonic setting (greater than 25 km depth). According to the Smithsonian Global Volcanism Program's official record, the volcano has a confirmed total of 27 eruptions spanning from its earliest recorded activity around 2650 BCE up to the 21st century CE.

The historical record distinguishes between prehistoric activity dated via calibrated radiocarbon methods and more recent events documented through direct observations and reports. The largest recorded Volcanic Explosivity Index (VEI) for the volcano is 3.0. Out of the 27 confirmed eruptions, 19 have recorded VEI observations.

Chronology and Eruption History

The documented activity at Tokachidake reaches back thousands of years. The earliest recorded eruption in the dataset occurred around 2650 BCE with a start year uncertainty of 200 years, determined through calibrated 14C isotopic evidence. Additional prehistoric and early historic eruptions are distributed across various centuries, including entries in the 14th century BCE, the 27th century BCE, the 1st, 4th, 6th, 10th, 11th, and 16th centuries CE, as well as multiple events in the 19th and 20th centuries CE.

Activity intensified in terms of direct observation during the 20th century, which accounts for 13 of the recorded eruptions. Notable historical sequences include:

• 1925–1927: An eruption starting on November 20, 1925, and ending on September 16, 1927, localized in the Shin-funkako activity area, reaching a VEI of 3.0 based on reported observations.
• 1962: An eruption occurring south of Shin-funkako from June 29, 1962, to September 16, 1962, also registering a VEI of 3.0.
• 2004: An eruption at the 1962-II Crater beginning on February 25, 2004, and concluding on April 19, 2004, with a VEI of 1.0.

The profile's last known eruption year is recorded as 2004, with the latest confirmed eruption starting on February 25, 2004. None of the recorded eruption entries in the provided database are marked as continuing.