Eruption history
VEI – Volcanic Explosivity Index: 0 = lava outpouring, 4 = like Eyjafjallajökull 2010, 6 = like Pinatubo 1991, 7 = like Tambora 1815. The scale is logarithmic – each step is about 10 times more material.
| Start | End | VEI | Vent and dating |
|---|---|---|---|
| 15 July 1919 | 15 July 1919 | 1 | W side of Onigajo caldera (O-jigokudani) · Observations: Reported |
| 22 January 1732 | October 1732 | 2 | NE flank of Yakushi-dake · Observations: Reported |
| 26 March 1686 | 27 March 1686 | 3 | Observations: Reported |
| 1450 ± 100 years | — | ? | Nishi-Iwate and Higashi-Iwate · Isotopic: 14C (uncalibrated) |
| 1300 ± 50 years | — | 3 | Higashi-Iwate (Myoko-dake) · Correlation: Tephrochronology |
| c. 150 | — | ? | Higashi-Iwate · Isotopic: 14C (uncalibrated) |
| c. 350 BCE | — | ? | Higashi-Iwate · Isotopic: 14C (uncalibrated) |
| c. 450 BCE | — | ? | Nishi-Iwate (O-jigokudani area) · Isotopic: 14C (calibrated) |
| c. 1,150 BCE | — | ? | Nishi-Iwate · Isotopic: 14C (uncalibrated) |
| c. 1,250 BCE | — | 3 | Higashi-Iwate · Isotopic: 14C (calibrated) |
| 1,500 BCE ± 300 years | — | ? | Higashi-Iwate · Correlation: Tephrochronology |
| c. 1,650 BCE | — | ? | Nishi-Iwate (O-jigokudani area) · Isotopic: 14C (calibrated) |
| c. 2,000 BCE | — | ? | Nishi-yama · Isotopic: 14C (calibrated) |
| 2,050 BCE ± 200 years | — | ? | Higashi-Iwate · Isotopic: 14C (calibrated) |
| 2,700 BCE ± 200 years | — | ? | Higashi-Iwate · Correlation: Tephrochronology |
| 2,950 BCE ± 50 years | — | ? | Nishi-Iwate · Isotopic: 14C (calibrated) |
| c. 3,050 BCE | — | ? | Higashi-Iwate · Isotopic: 14C (uncalibrated) |
| 3,250 BCE ± 500 years | — | 0 | Correlation: Tephrochronology |
| 3,750 BCE ± 100 years | — | ? | Higashi-Iwate · Correlation: Tephrochronology |
| 4,350 BCE ± 500 years | — | ? | Higashi-Iwate · Correlation: Tephrochronology |
| 4,450 BCE ± 500 years | — | 0 | Higashi-Iwate · Correlation: Tephrochronology |
| 4,850 BCE ± 50 years | — | ? | Nishi-Iwate · Isotopic: 14C (calibrated) |
| 4,900 BCE ± 100 years | — | ? | Higashi-Iwate · Isotopic: 14C (calibrated) |
| 5,650 BCE ± 50 years | — | ? | Nishi-Iwate · Isotopic: 14C (calibrated) |
| 6,300 BCE ± 100 years | — | ? | Nishi-Iwate · Isotopic: 14C (calibrated) |
| 6,450 BCE ± 1,600 years | — | ? | Correlation: Tephrochronology |
Data: Global Volcanism Program, Smithsonian Institution (#283240)