Ulawun (Papua New Guinea): Recorded Eruptions and Historical Activity

Ulawun is a stratovolcano located in Papua New Guinea at coordinates -5.05, 151.33, reaching an elevation of 2,334 meters above sea level within a subduction zone and continental crust tectonic setting (greater than 25 km). According to the Smithsonian Global Volcanism Program's official records, the volcano has a confirmed total of 47 eruptions spanning from the 17th century CE through the 21st century CE. The latest recorded eruption in the official collection began on March 27, 2025 CE, and concluded on April 7, 2025 CE, carrying a Volcanic Explosivity Index (VEI) of 2.0.

Chronology of Recorded Eruptions

The historical record for Ulawun begins in the 17th century CE, with the earliest recorded eruption starting on March 11, 1700 CE, which was documented through reported observations at a VEI of 2.0. Official records document a total of 47 confirmed eruptions, characterized by varying intensity levels measured using the Volcanic Explosivity Index (VEI), where the largest recorded VEI in the database reaches 4.0. Observation methods across the documented timeline rely primarily on reported observations.

The distribution of confirmed eruptions across centuries demonstrates how documented activity has been captured over time:

• 17th century CE: 1 recorded eruption
• 19th century CE: 2 recorded eruptions
• 20th century CE: 22 recorded eruptions
• 21st century CE: 22 recorded eruptions

While the database includes 47 total confirmed eruptions, representative records illustrate specific historical events across the centuries:

• March 11, 1700 CE – 1700 CE: Eruption number 15036, recorded via reported observations with a VEI of 2.0 and marked as non-continuing.
• January 15, 1970 CE – February 11, 1970 CE: Eruption number 15051, recorded via reported observations with a VEI of 3.0 and marked as non-continuing.
• October 20, 1999 CE – October 20, 1999 CE: Eruption number 15062, recorded via reported observations with a VEI of 1.0 and marked as non-continuing.
• June 26, 2019 CE – October 5, 2019 CE: Eruption number 22319, recorded via reported observations with a VEI of 4.0 and marked as non-continuing.
• March 27, 2025 CE – April 7, 2025 CE: Eruption number 22606, recorded via reported observations with a VEI of 2.0 and marked as non-continuing.

Understanding the Volcanic Explosivity Index (VEI)

The Volcanic Explosivity Index (VEI) provides a relative scale to describe the magnitude of explosive volcanic eruptions based on factors such as volume of products ejected and height of the eruption column. For Ulawun, all 47 recorded eruptions have associated VEI observations. The maximum recorded VEI in the official dataset is 4.0, representing moderate to large explosive events—such as the eruption spanning from June 26, 2019 CE, to October 5, 2019 CE—while other events registered lower index values, such as VEI 1.0, 2.0, and 3.0.