Myojinsho (Japan): Recorded Eruptions and Historical Activity

Myojinsho is a submarine caldera located in Japan within a subduction zone on oceanic crust less than 15 kilometers deep, sitting at an elevation of 11.0 meters. According to the Smithsonian Global Volcanism Program, the volcano has a confirmed record of 15 eruptions spanning from the 19th century CE into the 20th century CE. The earliest recorded eruption in the official dataset began on May 6, 1869 CE, and the latest recorded eruption occurred from January 29, 1970 CE, to June 16, 1970 CE.

Overview of Recorded Eruptions

The historical record for Myojinsho encompasses 15 confirmed eruptions between 1869 CE and 1970 CE. These events are distributed across two centuries: 3 confirmed eruptions occurred in the 19th century CE, and 12 occurred in the 20th century CE. Across the confirmed eruption record, all 15 events have associated Volcanic Explosivity Index (VEI) observations, with a largest recorded VEI of 2.0.

While the profile lists the last known eruption year as 1970 CE and the latest confirmed eruption date as January 29, 1970 CE, individual eruptions feature varying observation methods and durations. For example, an eruption starting on February 16, 1915 CE, and ending on July 16, 1915 CE, was noted with reported observations across multiple activity areas including 11 km east, 19 km NE, and 4 km SW. Another prominent event began on September 16, 1952 CE, and ended on October 16, 1953 CE, reaching a Volcanic Explosivity Index of 2.0.

Chronological Distribution of Activity

The documented activity at Myojinsho reflects distinct periods of unrest captured by observers over roughly a century. The earliest activity on record began on May 6, 1869 CE, with its activity area classified in the records as uncertain. Subsequent activity continued intermittently through the late 19th and mid-20th centuries, concluding its currently recorded timeline with the eruption that spanned from January 29, 1970 CE, to June 16, 1970 CE.