Spain is home to volcanoes, but activity is concentrated in distinct geographical areas. The country’s volcanic landscape is divided into two categories: the highly active oceanic islands and the geologically ancient, inactive zones on the Iberian Peninsula. While some regions require continuous scientific surveillance, others preserve volcanic remnants that have been quiet for millions of years. The presence of these structures confirms Spain has a significant, though unevenly distributed, volcanic history.
The Canary Islands Volcanic System
The Canary Islands represent the primary location of active volcanism within Spanish territory. This archipelago is a classic example of an oceanic volcanic province, where the islands were built up from the seafloor by successive eruptions. The geological structure is attributed to a mantle plume, or hotspot, which provides a stationary source of magma beneath the moving African tectonic plate. The western islands, such as La Palma and El Hierro, are the youngest and remain the most volcanically dynamic.
Recent activity includes the 2011–2012 submarine eruption off the coast of El Hierro. More recently, the Cumbre Vieja ridge on La Palma experienced a significant eruption that began in September 2021. This event was the longest recorded eruption on the island, lasting 85 days, and extruded an estimated 200 million cubic meters of lava. The lava flows dramatically altered the landscape and caused extensive destruction as they traveled to the sea.
The island of Tenerife also hosts Mount Teide, Spain’s highest peak and a massive stratovolcano, with its last eruption occurring in 1909. The western Canary Islands collectively form the only region in Spain where magmatic activity is continuous and poses a current natural hazard. Historical eruptions since the 15th century underscore the ongoing volcanic nature of this island chain.
Volcanic Fields in Mainland Spain
In stark contrast to the Canary Islands, the volcanic fields located on the Iberian Peninsula are geologically ancient and currently inactive. These mainland zones are the result of intraplate magmatism that occurred millions of years ago, distinct from the oceanic hotspot system. The two most notable areas are the Garrotxa Volcanic Zone in Catalonia and the Cabo de Gata region in Andalusia.
The Garrotxa Volcanic Zone, near the city of Olot, is the best-preserved volcanic field on the peninsula, featuring nearly forty volcanic cones and numerous lava flows. The last eruption was dated to around 11,000 years ago, but more recent research suggests volcanic activity may have continued until approximately 8,300 years ago. The region is classified as dormant, meaning there is no current expectation of an eruption. The landscape is characterized by Strombolian cones and craters, which are now protected within a natural park.
Further south, the Cabo de Gata volcanic complex in Almería is significantly older, with its main volcanic episodes occurring between 15 and 16 million years ago. This region is considered extinct, showing no signs of renewed activity in the modern geological era. The area is a remnant of a larger magmatic system that was primarily submerged beneath the Alboran Sea. Visitors can observe well-preserved volcanic domes, calderas, and striking columnar joints, evidence of its explosive, Miocene-era past.
Monitoring and Activity Status
Given the active nature of the Canary Islands, a sophisticated system is in place to assess and manage volcanic risk. The surveillance effort is spearheaded by the National Geographic Institute (IGN), which maintains a comprehensive Volcanic Surveillance Network. The Canary Islands Volcanological Institute (INVOLCAN) also contributes scientific data and expertise focused solely on the archipelago.
Monitoring methods rely on real-time data from various instruments to detect pre-eruptive signals. Extensive networks of seismometers record frequent small earthquakes that indicate magma movement beneath the surface. Ground deformation is tracked using GPS stations and interferometric synthetic aperture radar (InSAR), which detects subtle changes in ground elevation caused by magma accumulation. Surveillance also includes chemical analysis of gas emissions, such as sulfur dioxide, which signals the ascent of magma toward the surface.
This continuous vigilance allows authorities to maintain clear distinctions between active, dormant, and extinct volcanic areas. While the mainland fields are not actively monitored for eruption precursors, the Canary Islands are subject to constant oversight due to their demonstrated eruptive history and potential hazard. The monitoring system provides the scientific basis for civil protection decisions, ensuring public safety is prioritized across Spain’s diverse volcanic landscape.