The Canary Islands Volcanological Institute (Involcan) has clarified one of the most common questions about volcanic activity in Tenerife: what experts mean by risks in the short, medium, or long term.
This clarification follows the detection of a new volcano-tectonic seismic swarm on 30 August 2025, during which over 100 minor earthquakes were recorded in just over an hour.
A New Seismic Swarm Under Teide-Pico Viejo
According to Involcan, the Canary Islands Seismic Network registered the seismic swarm between 5:14 p.m. and 6:26 p.m. on 30 August. Out of the detected tremors, 49 were accurately located beneath the Teide-Pico Viejo complex, at depths of 4 to 7 kilometres.
The strongest event recorded a magnitude of 1.2, significantly below the threshold for feeling by the public.
What Causes These Earthquakes?
Involcan explains that volcano-tectonic earthquakes occur when pressure from underground fluids such as hot water or gases causes rocks inside the volcano to crack. These earthquakes typically occur in clusters, known as seismic swarms, where numerous small tremors happen in a short period.
In Tenerife, such swarms are not unusual; since 2017, over 110 swarms have been documented. Most of these are linked to the injection of magmatic fluids into the island’s hydrothermal system, a process observed by scientists since 2016.
Additional signs of volcanic activity on Teide reinforce this understanding:
- A rise in CO₂ emissions from the crater.
- Slight ground deformation to the northeast of the peak, detected in 2024.
Is an Eruption Imminent?
Despite these signs, Involcan stresses that there is currently no evidence indicating an increased likelihood of an eruption in the short or medium term. However, scientists emphasise that Teide’s system is active, and the persistence of swarms, gas emissions, and deformation suggests that activity may evolve in the long term.
Involcan summarises: “An eruption will happen sooner or later, but there are no indications of immediate risk.”
Clarifying the “Time Frames”
To address public uncertainty, Involcan has provided clear definitions of the different time horizons:
- Short term: hours to days.
- Medium term: weeks to a few months.
- Long term: several months, years, or even decades.
Reinforced Monitoring
Involcan continues to maintain and strengthen volcanic surveillance in Tenerife through a network of permanent monitoring stations and regular scientific campaigns. This includes constant measurements of seismic activity, gas emissions, and ground deformation, ensuring that any changes in the island’s volcanic system are detected as early as possible.
The seismic swarm of August beneath Teide is part of a recurring pattern of volcanic unrest observed over nearly a decade. While there is no short- or medium-term threat, Involcan reminds residents that Tenerife’s volcanic system is active and will eventually erupt in the future. Thanks to continuous monitoring, scientists aim to provide the public with clear and timely information should the risk level change.
