Mount Fuji at a Glance
Mount Fuji is an active stratovolcano on Honshu, Japan, last erupted in 1707–1708, and formed by subduction of the Philippine Sea Plate beneath the Eurasian Plate. Its classic cone developed mainly during the Fujiyama phase between about 100,000 and 10,000 years ago, with the current summit shape refined by post-8000 BP activity. Human records document eruptions from 781 CE to 1708, after which the volcano entered a quiescent period that continues today. Below is a concise, verified snapshot of Fuji’s age and key milestones.
Mount Fuji Formation Timeline
| Attribute | Verified Detail | Source Type |
|---|---|---|
| First basaltic eruptions | Approx 100,000 years ago | Geological stratigraphy |
| Major cone-building (Fujiyama phase) | ~100,000–10,000 years ago | Tephra and geological mapping |
| Summit formation and current shape | Refined after ~8000 BP | Geological and radiocarbon dating |
| Earliest written eruption record | 781 CE (mild activity) | Historical documents |
| Last eruption | 1707–1708 (Hōei eruption) | Historical and volcanological records |
| Current status | Active but quiescent; monitored by JMA | Japanese Meteorological Agency |
Age in Geological Terms
Mount Fuji’s basement consists of older Mesozoic granites and sedimentary rocks uplifted during the Philippine Sea Plate subduction. Volcanism began as basaltic eruptions roughly 100,000 years ago. The Fujiyama phase built the iconic cone between about 100,000 and 10,000 years ago, with the summit refined after approximately 8000 years before present. Parapatitic and flank eruptions have continued into historical time, most recently the Hōei eruption of 1707–1708. Ongoing seismicity, ground deformation, and gas signals indicate the system remains active, though in a presently quiescent state.
Eruption History Highlights
Written records extend Fuji’s eruption history back to 781 CE, with activity spanning mild events to large explosive eruptions. The Hōei eruption of 1707–1708 produced widespread ashfall across the Kanto and Kansai regions and shaped local landscapes. Between roughly 8000 BP and 1708, multiple flank eruptions formed scoria cones and lava flows on lower slopes. No eruption has been confirmed since 1708, yet fumarolic activity at the summit and occasional earthquakes confirm continued unrest. The Japan Meteorological Agency maintains continuous monitoring for future activity.
What Defines an Active Volcano Like Fuji
In volcanology, "active" means a volcano has erupted during the last 10,000 years and could erupt again. Mount Fuji meets this criterion via its post-8000 BP summit and flank activity and its historically documented eruptions. Dormancy periods can extend centuries; Fuji’s current quiet span began in 1708 and remains within typical recurrence intervals observed at stratovolcanoes worldwide. Monitoring includes seismic networks, GPS, gas geochemistry, and visual surveillance to detect renewed unrest.
Key Facts at a Glance
- Type: Active stratovolcano (basaltic to andesitic composition)
- Age: First eruptions ~100,000 years ago; major cone building to ~10,000 years ago
- Last eruption: 1707–1708 (Hōei eruption)
- Current status: Active but quiescent; closely monitored by Japan Meteorological Agency
- Highest point: 3,776 meters (12,389 feet), Japan’s highest peak
- Cultural status: National monument and UNESCO World Heritage Site (2013)
Practical Context and Monitoring
Understanding Mount Fuji’s age and behavior is essential for risk communication, land use planning, and visitor safety. Although the present quiet period is not unusual for Fuji, authorities maintain preparedness through hazard maps, evacuation plans, and public messaging. Scientific study of Fuji’s lavas and tephra improves models for future eruptions and supports long-term volcanic risk reduction. Regular updates from the Japan Meteorological Agency provide the most reliable, evidence-based outlook for residents and travelers.