Northern EPR at 9.8°N (Undersea Features): Recorded Eruptions and Historical Activity

Northern EPR at 9.8°N is an undersea volcanic feature consisting of fissure vents located along an oceanic rift zone at a depth of -2,500 meters. According to the official record from the Smithsonian Global Volcanism Program, the system has a confirmed eruption count of 18, spanning from prehistoric periods through recent observations.

Geographic and Tectonic Setting

This volcanic system is situated in an undersea environment along the East Pacific Rise, categorized within a rift zone and oceanic crustal setting of less than 15 kilometers depth. The geographic coordinates place the feature at latitude 9.83°N and longitude -104.3°W in Undersea Features.

Recorded Eruption History

The confirmed eruption record for Northern EPR at 9.8°N includes 18 distinct events with a largest recorded Volcanic Explosivity Index (VEI) of 0.0, where VEI observations are recorded for all 18 events. The historical record bridges millennia using a combination of isotopic dating methods for older events and direct observations for recent centuries.

Early activity documented in the record includes isotopic dating methods, such as Uranium-series analysis. For instance, an early event is noted around 5050 BCE (with an uncertainty of 8,000 years) along the EPR axis and areas east and west of the axis. Additional prehistoric activity is recorded across various centuries, including the 51st century BCE, 41st century BCE, 31st century BCE, 21st century BCE, and the 11th century BCE, as well as the 1st century BCE. Common historical centuries represented in the record include the 9th century CE, 10th century CE, 11th century CE, 12th century CE (with an uncertainty of 300 years), 16th century CE, 17th century CE, and 19th century CE.

In the 20th and 21st centuries, observational methods supplement isotopic studies. Confirmed eruptions occurred in 1988 (specifically starting July 2, 1988, along the East Pacific Rise at 9.27°N) and more recently at the Tica hydrothermal vent located around 9°50’N (9.83°N), where an eruption began on April 28, 2025, and ended on April 29, 2025.

Chronology of Activity by Century

The 18 confirmed eruptions are distributed across multiple centuries and millennia according to the official database:

• 51st century BCE: 1 event
• 41st century BCE: 1 event
• 31st century BCE: 1 event
• 21st century BCE: 1 event
• 11th century BCE: 1 event
• 1st century BCE: 1 event
• 9th century CE: 1 event
• 10th century CE: 1 event
• 11th century CE: 1 event
• 12th century CE: 1 event
• 16th century CE: 1 event
• 17th century CE: 1 event
• 19th century CE: 1 event
• 20th century CE: 4 events
• 21st century CE: 2 events