Monowai (New Zealand): Recorded Eruptions and Historical Activity

Monowai is a submarine stratovolcano located in New Zealand with a summit elevation of -132 meters below sea level. Situated within a subduction zone on oceanic crust less than 15 kilometers thick, Monowai has a documented history of underwater activity captured by specialized observation methods.

According to the Smithsonian Global Volcanism Program's structured record, Monowai has a total of 25 confirmed eruptions spanning from the late 20th century CE into the 21st century CE. Because the volcano lies beneath the ocean surface, scientists frequently rely on hydroacoustic (hydrophonic) observations to detect and record its activity.

Recorded Eruption Timeline and Distribution

The historical record for Monowai begins with its earliest recorded eruption on April 16, 1977 CE, which was documented using hydrophonic observations with a Volcanic Explosivity Index (VEI) of 0.0. Activity continued across subsequent decades, divided between the 20th and 21st centuries CE:

• 20th Century CE: 14 confirmed eruptions occurred between 1977 CE and the close of the century. Examples include events on June 16, 1986 CE, and a period starting December 15, 1997 CE, through February 4, 1998 CE.
• 21st Century CE: 11 confirmed eruptions took place, extending up to the latest recorded events in 2014 CE.

The largest recorded Volcanic Explosivity Index (VEI) for Monowai in the official record is 1.0, associated with summit activity starting on January 1, 2014 CE. A subsequent submarine eruption was recorded starting on October 16, 2014 CE, and concluding on November 5, 2014 CE, with a VEI of 0.0. The last known eruption year listed in the volcano profile is 2014 CE.