Turrialba (Costa Rica): Recorded Eruptions and Historical Activity

Geological Profile and Location

Turrialba is a stratovolcano located in Costa Rica at latitude 10.025° N and longitude -83.767° E. It stands at an elevation of 3,340 meters above sea level in a subduction zone setting with continental crust thicker than 25 kilometers. The feature is cataloged by the Smithsonian Global Volcanism Program under volcano number 345070.

Recorded Eruptive History and Century Distribution

The confirmed record for Turrialba contains 21 eruptions, spanning from 7260 BCE to 2022 CE. Evidence methods range from calibrated radiocarbon isotopic analysis for prehistoric events to reported observations for modern historical events.

Across the recorded timeframe, confirmed eruptions are distributed by century as follows:

• 73rd century BCE: 1 eruption
• 15th century BCE: 1 eruption
• 12th century BCE: 1 eruption
• 9th century BCE: 1 eruption
• 1st century CE: 1 eruption
• 7th century CE: 1 eruption
• 14th century CE: 1 eruption
• 19th century CE: 4 eruptions
• 21st century CE: 10 eruptions

Explosivity Index and Representative Eruptive Episodes

Out of the 21 confirmed eruptions in the dataset, 15 have assigned ratings on the Volcanic Explosivity Index (VEI). The maximum recorded explosivity reached VEI 4.0 during an eruption dated to approximately 40 CE (with an uncertainty of ±50 years), which was active in the Central summit crater and documented through calibrated radiocarbon isotopic dating.

Earlier prehistoric activity includes an eruption starting around 7260 BCE (±300 years uncertainty) centered at the NE summit crater, identified via radiocarbon analysis. Another radiocarbon-dated eruption occurred around 640 CE (±40 years uncertainty).

In modern observational records, an eruption began on January 16, 1866, and concluded on May 8, 1866. This event registered a VEI of 3.0 and involved activity in the Central and SW summit craters. Activity in the 21st century CE accounts for 10 confirmed eruptions in the database, including a single-day eruption on July 17, 2022, which registered a VEI of 1.0 based on reported observations.