Askja — Highland Caldera
Remote highland caldera with stunning Víti crater lake — famous 1875 eruption and Apollo astronaut training ground
Askja is a composite caldera complex in the Dyngjufjöll Mountains of the central highlands. The volcano rises to 1,519 m, and the largest caldera contains a deep crater lake (Öskjuvatn). This otherworldly landscape served as a training ground for Apollo astronauts preparing for the Moon landing.
Volcanic System
Askja's nested calderas hold two remarkable lakes: the vast Öskjuvatn (Iceland's second deepest at 220 m) and the smaller, geothermally heated Víti crater with its milky turquoise water.
The contrast between the cold, dark Öskjuvatn and the warm, vivid Víti creates one of Iceland's most otherworldly landscapes — the same qualities that drew NASA to use this terrain for lunar training.
- Large caldera complex: 50 km²
- Part of Dyngjufjöll Mountains
- Peak elevation: 1,519 m
- Contains Öskjuvatn crater lake (Iceland's second deepest at 220 m)
- Multiple eruption sites within caldera
- Surrounded by black sand desert
Apollo Training Ground
In 1965 and 1967, NASA sent Apollo astronauts to Askja to train for the Moon landing. The lunar-like landscape, volcanic craters, and basalt formations provided an ideal environment to practice geology and rover operations before the historic Apollo 11 mission.
Víti Crater Lake
Víti (meaning 'Hell' in Icelandic) is a stunning turquoise-blue crater lake formed during the 1875 eruption. The geothermal-heated water reaches temperatures of 20–60°C, creating a dramatic contrast against the dark volcanic rock.
Swimming in Víti has been a popular tradition, with water temperatures around 20–25°C. However, access may be restricted at times due to landslide risk on the steep crater walls. Check current conditions before visiting.
- Diameter: ~150 meters
- Water temperature: 20–60°C
- Turquoise color from minerals
- Formed in 1875 eruption
- Steep descent to water's edge — check current restrictions
The 1875 Eruption
Askja's most famous eruption occurred on March 29, 1875, one of Iceland's most powerful and consequential volcanic events. An explosive Plinian eruption ejected huge volumes of tephra. Ashfall darkened daytime skies across eastern Iceland and deposited ash as far as Sweden, Norway and Germany.
This catastrophic event led to crop failure and livestock deaths, triggering a significant wave of emigration from Iceland. Approximately 2,000 Icelanders left for Canada and the USA as a result.
- March 29, 1875 — Plinian explosive phase
- Ash cloud reached 25+ km high
- Tephra covered eastern Iceland
- Created Víti explosion crater
- Ash reached Sweden, Norway & Germany
- Triggered mass emigration to North America (~2,000 people)
Eruption History
- 10 Jul–early Aug 1961: Effusive eruption produced basaltic lava flows (Vikrahraun) covering ~15 km²
- 1920s–1930: A series of small eruptions occurred between 1921 and 1930
- 29 Mar 1875: Catastrophic Plinian eruption — Iceland's most devastating volcanic event of the era
- 2021–present: Caldera floor has uplifted ~70 cm; seismic swarms (e.g., March 2024) indicate magma accumulation
Visiting Askja
Askja is one of Iceland's most remote and challenging destinations, accessible only in summer via F-roads requiring 4WD vehicles. Route F88 stretches 85 km from the Ring Road across black sand desert to Askja's caldera. The journey itself is an adventure, crossing rivers and traversing one of Europe's last true wilderness areas.
Due to the challenging access, many visitors choose guided super jeep tours or bus tours from Mývatn or Akureyri. These tours handle the difficult driving and provide expert knowledge about the area's geology and history.
- Route: F88 (Askja Road) — 4WD essential
- Season: Late June to early September
- Distance: ~85 km from Ring Road
- Journey time: 2–3 hours each way
- Popular stop: Herðubreið mountain (the Queen of Icelandic Mountains)
- River crossings may be required
- Dreki Hut: Mountain hut and campsite at destination
Safety Information
Check road conditions at road.is before departure. 4WD with high clearance required. River crossings may be necessary. Bring extra food, water, and warm clothing. Cell phone coverage is limited or nonexistent. Register your trip at safetravel.is.