Kaldárhraun og Gjárnar

Background

History & Background

Kaldárhraun was formed by volcanic eruptions on the Reykjanes Peninsula roughly 2,000–3,000 years ago. The area lies along the boundary between the Eurasian and North American tectonic plates, where ongoing geological activity continues to shape the landscape. Today, it is an important geological site, offering insight into volcanic processes and tectonic movement in Iceland.

Kaldárhraun and its associated fissures are part of a large lava field located near Hafnarfjörður in Iceland’s Capital Region. The area lies on the Reykjanes Peninsula, one of the most geologically active parts of the country, where the Eurasian and North American tectonic plates are gradually moving apart. The lava field was formed during volcanic eruptions approximately 2,000 to 3,000 years ago. As the lava cooled and solidified, tectonic forces continued to act on the region, creating cracks and fissures—known locally as gjárs—that run through the landscape. These features vary in size and depth, adding complexity and visual interest to the terrain. Over time, moss and other vegetation have slowly colonized the lava, creating a green layer over the dark volcanic rock. This fragile ecosystem develops very slowly and is highly sensitive to disturbance. Today, Kaldárhraun is a popular area for walking and outdoor exploration. Its proximity to urban areas makes it easily accessible, while its geological features provide insight into the natural forces that continue to shape Iceland.