Mount Suswa is a hidden geological treasure in Kenya’s southern Rift Valley. While often overshadowed by nearby Mount Longonot or the dramatic escarpments of Hell’s Gate, Suswa offers something truly unique: a double crater volcano, extensive lava tube systems, active geothermal vents, and a striking volcanic plug rising from its core.
This ancient shield volcano tells a story of powerful earth forces, deep-time tectonics, and evolving landforms — all accessible to hikers, scientists, and nature lovers alike.
🌀 What Makes Suswa’s Double Crater So Unique?
Mount Suswa’s defining feature is its twin caldera system — a rare geological formation that sets it apart from other volcanoes in the region.
Structure Overview:
- Outer Crater: Approximately 10 km in diameter, forming the broad rim of the mountain.
- Inner Crater: A smaller, circular collapse within the outer crater, measuring around 5 km in diameter and several hundred meters deep.
- Volcanic Plug: A massive, dome-like rock formation sits in the center of the inner crater.
This nested caldera design is the result of multiple phases of volcanic activity, where the central magma chamber emptied and collapsed not once, but twice — creating two concentric rings. It’s one of the few documented double craters in the world, and the only one in Kenya that’s still relatively undisturbed.
🕳️ Inside Mount Suswa’s Ancient Lava Tubes
On the southern and southeastern slopes of Suswa, beneath the surface, lies a network of extensive lava caves — some stretching for hundreds of meters through the cooled basalt.
These lava tubes formed when the outer surface of a lava flow solidified while molten lava continued to flow beneath. Once the eruption ceased, the underground lava drained away, leaving behind empty, tunnel-like caverns.
Key Features:
- Multiple chambers and interconnecting tunnels
- Lava stalactites and flow ridges
- Skylights from collapsed cave roofs
- Home to thousands of bats and the iconic Baboon Parliament — a cave where baboons roost at night
These caves provide rare insights into volcanic flow dynamics and are a must-see for visitors with an interest in speleology or geology.
🌋 10 Incredible Volcano Facts About Mount Suswa
- It’s a shield volcano, not a stratovolcano — meaning it formed from slow-flowing lava that spread wide rather than erupting explosively.
- The double crater is one of only a few like it in the world, and the best preserved in East Africa.
- The inner crater contains its own microclimate, with cooler, more humid conditions and dense vegetation.
- Mount Suswa’s lava caves are among Kenya’s largest and most complex — and still being mapped.
- It’s still geothermally active, with steam vents that continue to emit heat and gases.
- The volcanic plug at the center may be a resurgent dome or intrusive rock body from later eruptions.
- The outer slopes show classic pahoehoe and a’a lava textures, evidence of varying flow speeds.
- Steam vents are used by local Maasai for water harvesting, showcasing geothermal-human interaction.
- It is part of the Great Rift Valley fault system, a zone of ongoing tectonic stretching.
- It’s accessible without being commercialized, making it a rare, untouched geological classroom.
🌫️ Mount Suswa’s Steam Vents: A Volcanic Phenomenon
Even though Mount Suswa hasn’t erupted in thousands of years, it remains geothermally alive. Visitors can witness this through active fumaroles — steam vents that emit heat and gases from deep underground.
These vents appear as cracks in the earth or small openings in lava rock, often hissing with vapor, especially on cool mornings.
Why They Matter:
- Indicate residual volcanic heat beneath the surface
- Support unique micro-ecosystems around warm vents
- Used by Maasai for steam-based water harvesting systems
- Serve as natural hot saunas during the cold season
Walking through these vents — especially near sunrise — is one of the most surreal experiences on the mountain, as the landscape seems to breathe beneath your feet.
🧬 The Geological Story of Mount Suswa
Mount Suswa’s geological history is tied to the tectonic processes of the East African Rift System — a massive fracture zone where the African continent is slowly splitting apart.
Timeline of Formation:
- Initial Volcanic Activity: Basaltic lava eruptions formed the base of the shield volcano.
- Caldera Collapse 1: As magma drained, the summit collapsed, forming the outer crater.
- Renewed Eruptions: Lava continued to rise, building pressure and creating a plug or dome.
- Caldera Collapse 2: A second collapse formed the inner crater, revealing new layers of lava rock.
- Post-Volcanic Activity: Erosion sculpted the landscape, while geothermal vents and lava tubes remained active.
The result is a layered, multigenerational volcanic landscape — rich with history, complexity, and scientific intrigue.
🪨 What Is the Plug in the Center of Mount Suswa?
If you descend into Suswa’s inner crater, your eyes are immediately drawn to a rocky hill that rises from the center — this is the volcanic plug.
What is it?
- A solidified mass of lava that once sealed the volcano’s central vent.
- Sometimes called a resurgent dome or intrusive plug, it may represent later volcanic activity after the inner crater collapse.
- Its resistance to erosion compared to surrounding materials caused it to stand taller over time.
Hiking around the inner crater gives you multiple views of this dramatic feature — it’s photogenic, symbolic, and geologically essential to understanding Suswa’s story.
🧭 Final Thoughts: A Living, Breathing Volcano
Mount Suswa isn’t just another mountain. It’s a dynamic record of the Earth’s forces in motion — a tectonic storybook, a volcanic museum, and a living geology classroom.
From steam hissing through ancient vents to baboons sheltering in lava tubes, every rock and ridge tells part of Suswa’s story. Whether you’re a scientist, student, hiker, or curious traveler, you’ll leave not just with great photos — but with a deeper respect for the power of the planet beneath your feet.