Four Azorean volcanic systems are sitting at alert level V1. Furnas joined them on Tuesday
CIVISA raised the Furnas volcano on São Miguel to V1 after a day of low-magnitude tremors and one magnitude 2.9 quake felt in the village. V1 is the second of eight rungs, and three other Azorean systems have been on it for months.
The Azores seismic and volcanic monitoring centre raised the alert level on the Furnas volcano to V1 on Tuesday, after a day of unusual activity under the municipality of Povoação on São Miguel.
The tremors began at 11.47am local time. Almost all of them were too small to notice. One was not: a magnitude 2.9 quake at 4.41pm, with its epicentre roughly four kilometres west-southwest of Furnas, felt at a maximum intensity of V on the Modified Mercalli scale in the village itself. Intensity V is the point where a quake stops being something only instruments notice.
What V1 actually means
CIVISA runs an eight-rung volcanic alert scale. V0 is a system at rest, which is where a volcano spends most of its existence. V1, one step up, describes a system in metastable equilibrium with weak activity. V7, at the far end, is a magmatic or hydromagmatic eruption already under way with colossal explosivity.
So there are six rungs between what happened at Furnas this week and an eruption. The V1 classification holds for eight days unless something changes it sooner.
The three nobody mentioned
Here is the part the coverage left out. Read CIVISA’s own alerts page and count the entries: with Furnas added, four Azorean volcanic systems are at V1 simultaneously.
Santa Bárbara on Terceira has been at V1 since July. So has the West Terceira Fissural Volcanic System. And the Manadas Fissural Volcanic System on São Jorge has held the classification since March 2024 — two and a half years of metastable equilibrium, during which nobody stopped living, farming or flying there.
That context is what usually goes missing when one of these alerts reaches the news wires. In an archipelago built entirely by active volcanism, V1 is not an evacuation notice. It is a state that large parts of the Azores occupy for long stretches, and what changes when the level goes up is the intensity of the monitoring, not daily life.
It is the same geology, incidentally, that put these nine islands where they are — and the same islands where Santa Maria is preparing to host orbital launches.
Image: Jules Verne Times Two / Wikimedia Commons (CC BY-SA 4.0)
