The alert level in the West Terceira Fissural Volcanic System has risen to V3 (reactivation phase), the same level attributed to the Santa Bárbara volcano, revealed this Wednesday, November 26, the Institute of Volcanology at the University of the Azores.
According to a statement from the Institute of Volcanology of the University of the Azores (IVAR), its Crisis Office met to assess seismovolcanic activity on the Azorean island of Terceira and “maintained the V3 alert level on the Santa Bárbara Volcano, having also raised the alert on the Western Fissural Volcanic System of Terceira to V3”.
“Throughout the month of November, seismic activity on the island, although of low magnitude, has continued to be clearly above reference levels, maintaining an increasing trend, in particular, in the perimeter of the Santa Bárbara Volcano and in the Western Fissural Volcanic System of Terceira, more specifically in the Mistérios Negros section”he added.
The IVAR indicates that this fact “has determined the occurrence of several earthquakes felt by the population”.
“In the same period, and although not very intense, crustal deformation continued to occur in the area where the seismovolcanic crisis was developing”, he adds.
Also according to the note, so far “no significant seismic signals of magmatic or hydrothermal origin have been recorded, nor have there been any gas anomalies that could be related to the current seismovolcanic crisis”.
Despite the increase in seismic activity, the IVAR Crisis Office explains that it decided to maintain the V3 alert level on the Santa Bárbara volcano and raise the alert on the Western Fissural Volcanic System of Terceira to V3, due to the fact that “the section of Mistérios Negros corresponds to a fracture zone where the two volcanic systems intersect and communicate”.
In conclusion, IVAR highlights that “any change in the observed pattern of activity could lead to the adjustment of the aforementioned alert levels, so it is important to continue monitoring the situation through official civil protection channels”.
In the same note, the Azores Seismovolcanic Information and Surveillance Center (CIVISA) recommends that self-protection measures be adopted appropriate to the activity in progress, “to minimize the risks arising from the possible occurrence of an earthquake of greater magnitude or the development of slope movements at the level of unstable slopes and the coastline”.
On November 6, IVAR raised the alert level of the Santa Bárbara volcano, on Terceira island, to V3.
Since June 24, 2022, seismic activity in the Santa Bárbara volcano, on the island of Terceira, has been “above normal reference values”, with the most energetic event occurring on January 14, 2024, with a magnitude of 4.5 on the Richter scale.
In June 2024, the alert level was raised to V3, but was lowered again to V2 (volcanic system undergoing instability) in December of that year, taking into account the reduction in seismic activity and crustal deformation.