A magnitude 3.1 earthquake shakes Granada: these are the municipalities where it has been felt

The National Geographic Institute (IGN), through the National Seismic Network, follows a chained procedure to detect, review, and confirm the location and magnitude of an earthquake. What the public sees in the “IGN Earthquakes” viewer and in the official catalog is the result of an initial automatic solution that is later refined through instrumental analysis and macroseismic data provided by the population.

1. Initial automatic detection

The process begins at the seismic stations of the National Seismic Network, distributed throughout Spain and nearby areas. Each station continuously records ground vibrations and sends the data in near real-time to the IGN processing center.

Automatic algorithms detect changes in the signals that may correspond to an earthquake (arrival of P and S waves) and, when several stations record the same event, the system:

• Calculates a first location of the epicenter (coordinates and estimated depth).
• Assigns an initial magnitude, based on the amplitude and duration of the waves.
• Determines an origin time of the seismic event.

This preliminary solution is published very quickly in the catalog and in the latest earthquakes viewer, precisely so that Civil Protection and the public have an immediate reference. The IGN itself warns that these data are provisional and may be modified as the analysis progresses.

2. Instrumental review by seismologist staff

After automatic detection, seismologist technicians manually review the event. This phase is key to confirm or correct:

• The arrival of seismic phases (P and S waves) at each station, precisely adjusting arrival times.
• The selection of the most reliable stations for that event (due to distance, background noise, or quality of the record).
• The location of the hypocenter, recalculating coordinates and depth.
• The magnitude, using the most appropriate scale (for example, moment magnitude Mw in relevant earthquakes).

At this stage, data from collaborating networks (such as regional institutes or universities) are incorporated when available. The more quality stations involved, the more precise the location and better the magnitude characterization.

3. Parameter adjustment and quality control

Reviews may lead to notable changes in the initial parameters. Recent experience in the seismic series of Granada shows that, after the first hours, the National Seismic Network:

• Has recalculated magnitudes (for example, an earthquake initially reported with one magnitude and, after review, adjusted to a slightly different value).
• Has corrected depths, sometimes changing from several kilometers to practically superficial solutions (0 km in the catalog, as a revisable value).
• Has adjusted the exact position of the epicenter, even changing the reference locality used to describe it.

All this work is accompanied by internal quality controls: consistency between stations, coherence with the historical seismicity of the area, and comparison with other seismological centers when appropriate.

4. Integration of macroseismic information

In parallel with instrumental analysis, the IGN collects information on how the earthquake was felt through the online macroseismic questionnaire. People who noticed the tremor indicate:

• Where they were and at what time they perceived the movement.
• What type of shaking they felt and how people reacted.
• What objects moved or fell and what damages were observed.

With these responses, the macroseismic intensity is estimated in each locality, which is not the same as magnitude. Magnitude describes the energy released at the focus; intensity reflects the effects on people and buildings. This information complements the instrumental analysis and may motivate nuances in the interpretation of the event.

5. Publication and update of the catalog and bulletins

Once the data are reviewed, the IGN updates the official earthquake catalog and the “IGN Earthquakes” viewer. There are shown:

• Definitive location of the epicenter and estimated depth.
• Revised magnitude.
• Maximum observed intensity, when available.
• Map of localities where the seismic event was felt.

In more relevant events or with potential impact on the population, the information is also incorporated into bulletins and statements that serve as reference for Civil Protection, administrations, and media. The process is not static: if new data or additional stations allow further refinement of the solution, the IGN reviews again and the catalog reflects those modifications.

In summary, the location and magnitude of an earthquake in Spain are not a single immutable datum, but the result of an iterative procedure: rapid automatic detection, detailed manual review, integration of citizen observations, and continuous updating of official records.

In the Spanish legal system, 112 is not a specialized “seismic service,” but the single and free access channel to emergency services, also when the emergency derives from an earthquake or tsunami. Its competencies are defined by combining civil protection regulations and telecommunications regulations.

Basic regulatory framework

From the civil protection perspective, Law 17/2015, of July 9, on the National Civil Protection System configures civil protection as a public service responding to emergencies and disasters, including those caused by natural causes such as earthquakes. The law emphasizes:

• The existence of alert networks and operational coordination centers connected among themselves (state and regional).
• The need for preventive information and alert programs for the population in all civil protection plans.
• The role of competent emergency coordination bodies of the Autonomous Communities as essential parts of the National Civil Protection System.

All this is the institutional “ecosystem” in which the regional 112 is inserted, acting as the entry point for alerts and as a response coordination center.

From the telecommunications side, Royal Decree 903/1997, of June 16, regulates access to the 112 emergency call service. It establishes that:

• 112 is the European single telephone number for emergency calls in Spain.
• Through 112, assistance is requested, “in cases of urgent need,” from the competent public services in health emergencies, fire extinction and rescue, citizen security, and civil protection.
• Access is free and operators must route calls to the reception center of the 112 service corresponding to the geographic area of origin and provide location data within technical possibilities.
• Entities managing 112 must adopt the necessary measures and collaboration agreements with emergency services to guarantee a “rapid, orderly, and effective” action.

Competencies of 112 in seismic risks

a) Reception and first management of seismic alerts

In an earthquake or tsunami, 112 has the competence to:

• Receive all calls from the public related to personal injuries, collapses, trapped people, secondary fires, supply cuts, etc.
• Locate the emergency (thanks to network information and data provided by the caller).
• Classify and prioritize alerts, forwarding them to competent services (emergency health, firefighters, security forces, municipal/regional civil protection…).

It does not decide seismic risk management policy, but it is the operational node where the citizen demand for help is concentrated in real time.

b) Activation and coordination with civil protection and other services

Within the framework of Law 17/2015 and the Basic Civil Protection Standard (approved by Royal Decree 524/2023), regional 112 centers usually coincide with territorial operational coordination centers. Therefore, in case of an earthquake:

• They activate territorial and special civil protection plans for earthquakes/tsunamis, according to procedures approved by each Autonomous Community and the corresponding State Plan (for example, the State Plan for tsunami risk approved under Law 17/2015).
• They mobilize and coordinate, within their scope, firefighters, health services, security forces, civil protection volunteers, etc.
• They integrate into the National Civil Protection Alert Network and the National Emergency Monitoring and Coordination Center when the situation escalates to a national interest emergency.

c) Dissemination of alerts and warnings to the population

Law 17/2015 requires all civil protection plans to include preventive information and alert programs. Operationally, 112 centers:

• Collaborate in the dissemination of official alerts (for example, evacuation orders, confinement instructions, “stay away from the coast” in case of tsunami).
• Use the technical channels available in each territory (calls or loudspeakers, coordination with public alert systems via mobile telephony, sirens, media).
• Provide feedback to decision centers on the evolution of damages and needs, which influences the updating of alerts.

d) Distribution of competencies between State and Autonomous Communities

Legally, there is a dual competency basis:

• The State sets the bases of civil protection (Law 17/2015, Basic Standard, state plans for major risks) and the regulation of the 112 number and electronic communication services (Royal Decree 903/1997 and Telecommunications Law 11/2022).
• The Autonomous Communities, exercising their competencies in civil protection and organization of their services, create, organize, and manage 112 centers, determine their territorial deployment, their integration with municipal services, and specify operational protocols for earthquakes.

In summary, state regulations establish that 112 is the unique, free, and universal number to access emergency services and ensure that the system is integrated into the architecture of the National Civil Protection System. On that basis, the Autonomous Communities specify how 112 receives, manages, and coordinates emergencies caused by earthquakes or tsunamis in their territory.

With the information available in the consulted sources, it is not possible to give an exact and closed number of how many earthquakes with magnitude greater than 3 have been recorded in the province of Granada in the last decade. The National Geographic Institute (IGN) does provide the data through its seismic catalog, but in an interactive query format, not as a pre-calculated figure for the entire 2016‑2026 period and for the whole province.

What can be stated, based on recent IGN data cited in official notes and in the newspaper Demócrata, is that the province of Granada is among the areas of greatest seismic activity in the Iberian Peninsula and that, only in specific episodes of these years, dozens of earthquakes with magnitude equal to or greater than 3 have already accumulated.

What recent IGN data say about Granada

The consulted sources show several particularly intense episodes within the last decade:

• According to a Demócrata report on the August 2026 seismic series, from August 14 to August 18 the IGN located 432 earthquakes around Alhendín, Gójar, and La Zubia, all very shallow. Of these, nine reached or exceeded magnitude 3, including two moment magnitude earthquakes of 4.8 and others of magnitude 4.2, 4.0, and 3.9.
• Another article from the same media, also based on IGN data, raises the accumulated figure of that series to 621 seismic movements up to August 19, and specifies that ten of them had magnitude equal to or greater than 3. That is, in just a few days of 2026 there are already ten earthquakes above that threshold.
• The graphics article about earthquakes in Granada recalls that between December 2020 and August 2021 the Santa Fe and Atarfe area recorded more than 3,000 shallow earthquakes, six of them with magnitudes between 4 and 5. Although it does not detail how many between 3–3.9 there were, it is reasonable to infer that there were several dozen in that interval.

These two major episodes (the 2020–2021 series north of the capital and the August 2026 series south of Granada) show that, only in a few specific months within the decade, several dozen earthquakes with magnitude greater than 3 already accumulate in the province.

Why there is no single figure for the entire decade

The problem is not that the data do not exist, but how it is published. The IGN itself and the National Geographic Information Center maintain an application and a catalog (“IGN Earthquakes”) that allow consulting recent seismicity. According to a note from the Electronic Administration portal about the open geographic data applications of the CNIG, the seismic catalog:

• Allows narrowing the search by geographic area.
• Allows filtering by dates.
• Allows setting thresholds of magnitude, intensity, and depth.

That is, technically it is possible to obtain the exact number of earthquakes with magnitude greater than 3 in the province of Granada between any two dates (for example, from September 16, 2016, to September 16, 2026). But that operation must be done directly in the viewer or in the IGN data service, because it does not appear already summarized in any of the notes or analyses accessed.

How you could obtain the exact data

If you need a precise figure — for example, for a technical or academic work — the suggested procedure, based on what the consulted sources describe, would be:

• Access the seismic catalog of the National Geographic Institute or the “IGN Earthquakes” application, mentioned by the CNIG itself.
• Define the area or coordinates corresponding to the province of Granada (or use the administrative layer if the viewer offers it).
• Set the time range to the last decade (10 full years backward from the date you are interested in).
• Apply a filter of minimum magnitude strictly greater than 3.
• Count the events returned by the catalog or, if applicable, export the list and calculate the total.

In summary, recent sources from IGN and Demócrata confirm that, only in some specific series, Granada already records several dozen earthquakes with magnitude greater than 3. However, the exact accumulated number for the entire province and for the entire last decade can only be extracted by performing a direct query in the official IGN seismic catalog, as it is not offered in aggregated form in the reviewed documents.