The Canary Islands Volcanological Institute (Involcan) has shed light on one of the most frequently asked questions about volcanic activity in Tenerife: what experts mean when they speak of risks in the short, medium or long term.
This clarification comes after the detection of a new volcano-tectonic seismic swarm on 30 August 2025, during which more than 100 minor earthquakes were recorded within 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 more than 100 tremors detected, 49 were precisely located beneath the Teide-Pico Viejo complex, at depths of 4 to 7 kilometres.
The strongest event reached a magnitude of 1.2, far below the threshold of being felt by the population.
What Causes These Earthquakes?
Involcan explains that volcano-tectonic earthquakes occur when rocks inside the volcano crack due to pressure from underground fluids such as hot water or gases. They usually appear in clusters, known as seismic swarms, with many small tremors happening in the same area over a short period.
In Tenerife, such swarms are not unusual: since 2017, more than 110 swarms have been documented. Most are linked to the injection of magmatic fluids into the island’s hydrothermal system, a process scientists have tracked since 2016.
Other signs of volcanic activity on Teide reinforce the picture:
- 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 signals, Involcan stresses that there is currently no evidence pointing to 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 indicates that activity could 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 provided a clear definition of what experts mean by 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 measurement of seismicity, gas emissions, and ground deformation, ensuring that any change in the island’s volcanic system is detected as early as possible.
The August seismic swarm beneath Teide is part of a recurring pattern of volcanic unrest observed for 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 population with clear and timely information should the risk level change.
