Type: Stratovolcano (composite volcano)
Age: Formed roughly 400,000 years ago, with its last major eruption around 1860 (minor fumarolic activity may still occur).
Formation Process:
- Initial eruptions: Magma from deep beneath the rift rose through cracks, building layers of ash, lava, and volcanic rock.
- Cone building: Successive eruptions formed a large volcanic cone characteristic of stratovolcanoes.
- Caldera collapse: After massive eruptions emptied part of the magma chamber, the summit collapsed inward, creating a large caldera (crater) — about 8 km wide.
- Secondary activity: Small volcanic cones and ridges formed inside the caldera from later eruptions, giving Longonot its rugged inner crater walls.
Current landscape:
Mount Longonot’s steep slopes, radial ridges, and circular crater rim are classic examples of a collapsed stratovolcano — evidence of both constructive (lava building) and destructive (collapse) volcanic forces.
3. Formation of Hell’s Gate Gorge and Cliffs
Type: Rift valley gorge and geothermal area
Formation Age: Over the last few million years, during active rifting and volcanic eruptions in the area.
Formation Process:
- Rifting and faulting: As the land stretched and cracked, large fault lines formed, creating deep valleys and towering cliffs (e.g., Fischer’s Tower and Central Tower, which are volcanic plugs).
- Volcanic activity: Repeated eruptions from nearby volcanoes (like Longonot and Olkaria) deposited layers of lava and ash.
- Erosion: Over thousands of years, rainwater and geothermal streams cut through the soft volcanic rocks, carving out Hell’s Gate Gorge.
- Hydrothermal features: The area remains geothermally active, with hot springs, fumaroles, and geysers, showing that magma still lies beneath the surface.
