It is quite challenging to ascertain when a volcanic eruption will commence, let alone to foresee the location of a new one. On an island with a volcanic system as intricate as that of Tenerife – which is additionally unparalleled globally – and with so few indicators of recent volcanic activity, discovering an answer to this mystery is akin to taking a gamble. Nevertheless, science has endeavoured to address the question that every resident of Tenerife has pondered at least once: Where is the next eruption likely to occur? Although the response is contingent on probabilities which may or may not materialise, there is a particular area where the risk escalates: The West of Tenerife.
According to the insular action plan concerning volcanic risk (PAIV), devised in 2018, the region of greatest volcanic threat on the island is specifically The ridge that stretches from Teide to the Teno massif, commonly referred to as the Abeque ridge. Over the past 2,000 years, this has been the most volcanically active zone of the island, having recorded at least five historical eruptions, comparable to the 2021 event in La Palma – described as of a strombolian type with basaltic flows. “This region has been the most active in Tenerife over the last 20,000 years,” affirms Nerea Martín, a geographer and member of the Chair of Disaster Risk Reduction and Resilient Cities at the University of La Laguna (ULL), the group responsible for compiling this Report for the Cabildo de Tenerife.
To arrive at this conclusion, researchers utilised bibliographic references that had previously mapped the volcanic hazards of Tenerife (specifically a study undertaken by the Geological and Mining Institute of Spain in 2006) and incorporated data concerning seismic activity, recent eruptions – defined as those occurring in the last 2,000 years – and the density of more recent volcanic cones. In this study, the seismic data from recent years was not considered, as the report dates back to 2018, when a distinct trend had yet to be identified.
The most recent eruptions: from Garachico to Chinyero
This area has experienced some of the most significant eruptions on Tenerife Island. The most well-known is, due to its consequences, the black mountain (1706), whose flows ultimately descended to Garachico, completely obliterating the town that had served as a commercial port for the island for many decades, leading to a severe economic crisis in northern Tenerife.
In this locality, the Chinyero volcano (1909) appeared, which was the last volcano to erupt on the island of Tenerife. This eruption, notable for being one of the briefest ever recorded (just nine days), had minimal impact. Due to its brief duration, the lava remained several kilometres away from the first town in its path: Santiago del Teide. Residents of that time recounted that, after days of distress watching the lava flow down the hillside, many people from Tenerife came together and walked towards the source of danger, carrying an image of God and another of the Virgin. Upon reaching the lava flow, it soon altered its course, cooled down, and halted. A miracle that is still commemorated at the very site, where visitors can still see the cross that once stood before the lava flow.
Location in the Altos de Santiago del Teide where the Chinyero lava stopped. / Dm
The challenge posed by this region is not necessarily in the location where the volcanic cone may arise, which would be – as is the case with much of Tenerife – on the summits; but how the lava flow will navigate from that point to the coast. Thus, the slopes of the Abeque ridge, encompassing the municipalities of Santiago del Teide, Buenavista del Norte, Garachico, or Icod, are regarded as the second area most susceptible to experiencing the ramifications of a new eruption.
However, as Martín elucidates, the arrival of lava at the coast is not the typical occurrence in Tenerife. “Unlike La Palma, where most historical eruptions flow to the sea; in Tenerife, many remain at the summit,” the geographer emphasises, while warning: “Everything hinges on the duration of the eruption.”
Not all hazards come from lava
But as demonstrated in La Palma during the Tajogaite eruption, lava is not the sole threat associated with an eruption. A volcano emerging from this dorsal could also lead to forest fires due to the rain of lapilli and the ejection of volcanic bombs; the material projected could impact biodiversity and even contaminate local aquifers. In the nearby areas, there could be a rainfall of fine ash, and the possibility remains that, upon reaching the sea, phreatic explosions may occur.
Although this area presents the greatest danger, researchers do not dismiss the prospect that eruption centres could potentially arise in various other locations across the island. The third locality highlighted by the PAIV is the Teide National Park itself. There, several eruptions have transpired, including that of the Chahorra volcano, also known as the Teide Noses (1798), which lasted three months but inflicted no harm upon the population as it was confined to flooding the area around the Old Teide peak. It did, however, generate considerable seismic activity and the collapse of certain domes.
The fourth locality of heightened danger is situated in the north of Tenerife. This region – which encompasses San Juan de la Rambla, Los Realejos, La Orotava, and Puerto de la Cruz – has experienced only five eruptions in the last 6,000 years; nevertheless, the lavas emerging from this area can cause extensive destruction particularly associated with their “massive and exceedingly slow flows” that do not adhere to the topography.
A prediction that is impossible
Tenerife has become a subject of discussion following detection of “anomalous” activity by the National Geographic Institute (IGN) and the Volcanological Institute of the Canary Islands (Involcan) in the heart of the island. They explained that since 2016 there has been a rise in seismic activity and a shift in gas emissions. In 2023, these two precursors were accompanied by a slight land deformation, measuring just one centimetre. Such a small change that detection systems can barely register it. Notwithstanding this news, scientists have excluded the possibility of a short- or medium-term eruption occurring.
While they can – and must – carry out this type of hazard and intrinsic risk assessment concerning volcanic phenomena on an island with active volcanism, pinpointing with certainty what is set to occur in the coming years in Tenerife is nearly unfeasible. “We only possess 20 or 25 years of seismic records for the island; the situation is intricate “An eruption on the island has never been monitored,” they reiterate.
Tenerife features a complex and unique volcanic system, making any data-driven predictions all the more challenging. The island consists of a substantial volcanic complex that elevates over 7,000 metres from the ocean floor. It comprises ancient volcanic massifs (Teno, Anaga, and Adeje), active volcanic ridges (Ten and Hope), external explosive volcanoes (Montaña de Guaza, Caldera del Rey, and Montaña Pelada), fields of recent volcanoes (Granadilla or Scratch), and ultimately at the island’s summit, the stratovolcano Teide-Pico Viejo. “We possess a mixed system characterised by basaltic and monogenic eruptions like Tajogaite, coastal, explosive dynamics, and others with distinct processes within the Viejo Teide-Pico system, which maintains its magmatic chamber,” explains the volcanologist.
As if that were not sufficient, there is no volcanically active island worldwide that has a similar situation. “We are unaware of any location in the world with eruptive processes that has recently erupted,” Domínguez notes, emphasising that consequently, evaluating whether the data collected since 2016 will culminate in an eruption remains uncertain.” All these challenges render predicting where and when a new eruption may occur not only complicated but, in Domínguez’s view, “it indicates a lack of sense.”
In any case, Tenerife stands as one of the most closely monitored volcanic regions in Europe. The island houses 25 seismic stations operated by the IGN, along with 15 GNSS stations (to monitor land deformation), eight continuous gas measurement units, supplemented by data accrued from periodic water and fumarole sampling at Teide, as well as satellite data gathered weekly to assess deformation. Furthermore, the IGB is set to enhance the network of inclinometers that began installation in the area three years ago. “We are now introducing some underground to avoid interference from the summit temperatures,” reveals Domínguez.
