Catalonia registers around 1,500 earthquakes a year that almost nobody perceives

Catalonia experiences around 1,500 earthquakes each year, although most go unnoticed. The Cartographic and Geological Institute of Catalonia insists that prevention, not prediction, is key.

According to COPE, the region records about 1,500 earthquakes annually, but the vast majority are not felt by anyone. The head of the Geophysics Area at the Cartographic and Geological Institute of Catalonia, Sara Figueres, explained this in an interview on COPE Catalunya, where she argued that the key is in prevention, not prediction.

The most recent earthquake felt occurred on October 17 in the Ripollés region. It reached a magnitude of 2.5 on the Richter scale, caused no casualties, and left material damage on some roads.

The worst earthquake in Catalan history occurred on February 2, 1428, with its epicentre in Camprodon and an impact that reached 300 kilometres. In Queralbs, 150 people died, which was 90% of the population, and in Barcelona, between 20 and 40 people died due to the collapse of a rose garden on the facade of the Basilica of Santa Maria del Mar. It has been almost six hundred years since then.

In 2026, all four Catalan provinces will have a seismic hazard level above 5 on a scale of 12, which corresponds to moderate or strong intensity. Girona and the surrounding regions, as well as areas of Barcelona and Lleida, are rated at intensity VII (very strong) due to the presence of faults and the proximity of tectonic activity from the Pyrenees. The lowest risk is concentrated in municipalities in the south of Lleida and Tarragona.

"We cannot predict earthquakes, and for this reason, we must prevent them"
Sara Figueres, head of the Geophysics Area at the Cartographic and Geological Institute of Catalonia

Figueres maintains that there is no prediction method that allows us to know when, where, or with what magnitude an earthquake will occur. Earthquakes originate several kilometres deep, making it impossible to install devices that monitor a fault in real-time. Therefore, the useful tool is foresight, meaning assessing risk to design mitigation strategies.

The data from the Cartographic and Geological Institute also do not indicate the likelihood of an earthquake occurring in a specific area. What they measure is the probability that, if one occurs, it will exceed a certain level of intensity and seismic acceleration over a return period of 475 years.

Catalonia has intraplate seismicity. The faults are smaller than those in plate boundary zones, meaning that earthquakes are usually of lower magnitude. Nevertheless, the region records an earthquake of magnitude four every few years.

To address this risk, Civil Protection of the Generalitat keeps the Sismicat plan active, first approved in 2003 and periodically reviewed. It relies on data that the institute has been collecting for over twenty years.

The work involves calculating the probability of experiencing a certain level of damage in each municipality. With this vulnerability analysis, town halls, which are legally required to review their emergency plans, can define how to act quickly in the event of a future earthquake. The National Geographic Institute is now asking them to review and update their earthquake prevention plans.