Copahue (Chile-Argentina): Recorded Eruptions and Historical Activity

Copahue is a stratovolcano situated along the border between Chile and Argentina in a subduction zone and continental crust tectonic setting. Rising to an elevation of 2,953 meters, the volcano has a recorded history spanning 21 confirmed eruptions. According to official records from the Smithsonian Global Volcanism Program, these events range from deep pre-instrumental estimates to recent observations, with the latest recorded eruption taking place in October 2024.

Overview of Recorded Eruptions

The formal historical record for Copahue includes 21 confirmed eruptions identified through diverse investigative methods, ranging from uncalibrated radiocarbon isotopic dating for ancient events to direct human observation for modern activity. The earliest recorded eruption in the dataset is dated to 6820 BCE with a question mark modifier on its start date modifier, while the largest recorded Volcanic Explosivity Index (VEI) for the volcano is 2.0.

Eruptive frequency varies significantly across the centuries preserved in the official record. While isolated early entries document activity in the 3rd century BCE and the 69th century BCE, historical reporting intensifies markedly in more recent centuries. Specifically, the record shows 1 eruption in the 18th century CE, 1 in the 19th century CE, 8 in the 20th century CE, and 9 in the 21st century CE.

Historical Eruption Timeline Examples

The 21 confirmed eruptions span several millennia, utilizing different evidence methods depending on the era:

• 6820 BCE (Start Date Modifier: ?): Evaluated using isotopic methods involving uncalibrated 14C.
• July 2, 1944: Documented through reported observations.
• September 16, 1995: Recorded with reported observations originating from the Agrio Crater, registering a Volcanic Explosivity Index (VEI) of 2.0.
• June 16, 2020 to November 2, 2020: An eruptive period localized at the Agrio Crater with a VEI of 2.0, documented through reported observations.
• October 16, 2024 to October 27, 2024: A confirmed eruption with a VEI of 1.0, tracked via reported observations.

Out of the 21 total confirmed eruptions in the dataset, 17 include recorded Volcanic Explosivity Index (VEI) classifications. The maximum assigned VEI value across these events is 2.0. Copahue's last known eruption year in the profile overview is listed as 2024, aligning with the October 2024 eruption event.