Niigata-Yakeyama is a 2,400-meter-high lava dome volcano located in Japan at latitude 36.921° N and longitude 138.036° E. Formed in a subduction zone setting over continental crust thicker than 25 kilometers, the volcano has a recorded catalog of 20 confirmed eruptions in the Smithsonian Global Volcanism Program database. The documented activity ranges from ancient prehistoric events dated through tephrochronology to observational reports in the late 20th century CE.
Geological Profile and Eruptive Overview
As a lava dome, Niigata-Yakeyama's eruptive history includes explosive events and localized fissure activity. Across its 20 confirmed eruptions, 15 have determined Volcanic Explosivity Index (VEI) ratings. The largest recorded eruption reached VEI 4.0, while the earliest documented event dates to approximately 1900 BCE and the most recent confirmed eruption began on March 30, 1998 CE.
Chronological Distribution of Eruptions
Eruptive events at Niigata-Yakeyama span several millennia, with recorded occurrences concentrated across specific centuries:
- 19th century BCE: 1 eruption
- 18th century BCE: 1 eruption
- 7th century BCE: 1 eruption
- 9th century CE: 2 eruptions
- 10th century CE: 1 eruption
- 14th century CE: 1 eruption
- 18th century CE: 1 eruption
- 19th century CE: 2 eruptions
- 20th century CE: 10 eruptions
Key Recorded Events
The historical record combines geologic evidence methods such as tephrochronology with direct observational reports:
- c. 1900 BCE: The earliest recorded eruption in the catalog was identified using tephrochronological correlation, carrying a start-year uncertainty of ±1,050 years.
- 887 CE: Documented through historical observational reports, this eruption reached VEI 4.0, the highest VEI rating recorded for Niigata-Yakeyama.
- 989 CE: Confirmed through reported historical observations.
- 1949 CE: Active from February 5, 1949, to September 13, 1949, this VEI 2.0 eruption was centered along northeast-southwest (NE-SW) fissures on both sides of the summit.
- 1998 CE: The most recent confirmed eruption began on March 30, 1998, producing a VEI 1.0 event on the upper east flank of the volcano.
Frequently asked questions
How many eruptions are recorded for Niigata-Yakeyama?
The Smithsonian Global Volcanism Program records 20 confirmed eruptions for Niigata-Yakeyama, spanning from approximately 1900 BCE to 1998 CE.
What was the largest recorded eruption at Niigata-Yakeyama?
The largest recorded eruption occurred in 887 CE, reaching a Volcanic Explosivity Index (VEI) rating of 4.0.
When did Niigata-Yakeyama's most recent confirmed eruption take place?
The most recent confirmed eruption began on March 30, 1998 CE, on the upper east flank of the volcano, with a VEI of 1.0.
Sources and further context
Official datasets support the event-specific facts.