Ksudach (Russia): Recorded Eruptions and Historical Activity

Ksudach is a stratovolcano located in Russia, standing at an elevation of 1,007 meters within a subduction zone and continental crust tectonic setting. Maintained within the official record of the Smithsonian Global Volcanism Program, the volcano has a documented history comprising 15 confirmed eruptions. This activity spans a long chronological range, beginning with an earliest recorded eruption around 7900 BCE and extending through the centuries up to its latest recorded eruption in 1907 CE.

Eruption History and Chronology

The confirmed eruption record of Ksudach includes events documented across multiple millennia using various scientific methods, such as calibrated radiocarbon isotopic dating, tephrochronology correlation, and historical observations. The recorded events vary in magnitude, reaching up to a Volcanic Explosivity Index (VEI) of 6.0 for activity associated with the Ksudach V caldera around 240 CE (with a 100-year uncertainty margin).

The structured eruption record is distributed across several centuries, highlighting recurring periods of activity:

• 79th century BCE: Includes an eruption in the Ksudach III caldera area around 7900 BCE with a VEI of 5.0, determined via calibrated 14C isotopic evidence.
• 48th century BCE: Features an eruption in the southwestern part of caldera IV (Paryashchiy Utes) around 4750 BCE, identified through tephrochronology.
• 30th century BCE: Contains an event dated around 3000 BCE with a VEI of 4.0.
• 3rd century CE: Includes a major eruption in the Ksudach V caldera around 240 CE assigned a VEI of 6.0.
• 20th century CE: Concludes the currently recorded eruptive sequence with an event at the Stubel vent on March 28, 1907, recorded via direct reports with a VEI of 5.0.

Understanding the Record

Out of the 15 confirmed eruptions in the official database, 12 include Volcanic Explosivity Index (VEI) observations. The events are distributed unevenly across different eras, reflecting both prehistoric geological evidence gathered through field studies and historical reporting for more recent centuries. The latest recorded activity in the official dataset occurred on March 28, 1907.