Earthquake in Granada today: aftershocks following the largest quake since 1956

The National Geographic Institute (IGN), through the National Seismic Network, is the official reference in Spain for locating earthquakes and assigning parameters such as magnitude, depth, and intensity. According to various official notes and recent coverage, this data is not static: it is continuously reviewed and updated as technical analysis progresses and new records arrive.

The information about the Granada earthquakes of August 2026 illustrates this operation well. The articles explicitly state that the IGN catalog “is continuously updated as new data arrives” and that “all its recent information is subject to continuous review.” In the case of the main Alhendín earthquake, it is explained that the “latest available record” from the IGN already showed a “revised” depth different from that communicated in the first hours, and it is added that “this is not a strange contradiction”: the National Seismic Network recalculates location, depth, magnitude, and intensity as it incorporates more records.

From this information, the general procedure can be described, with caution, as follows:

1. Initial recording and provisional publication

• When an earthquake occurs, the stations of the National Seismic Network detect seismic waves and generate a first set of parameters: approximate location, preliminary magnitude, and depth. These values allow very rapid reporting to civil protection, administrations, and the public.
• Autonomous emergency notes citing the IGN (for example, about earthquakes in Almería, Ceuta, or Portugal) always refer to “provisional data” from the IGN disseminated shortly after the event, indicating that this first magnitude is initial and may change.

2. Review with more network data

• After this first solution, the IGN continues receiving and processing records from more seismic stations. The organization itself warns that, especially in the first hours, “all these parameters are subject to modifications as seismic analysis continues.”
• This review phase jointly affects the event record: location, depth, magnitude, and intensity are recalculated. Hence, as seen in Granada, the depth changed from a preliminary value of a few kilometers to a “revised depth” of practically zero, and the magnitude was fixed (for example, at 5.0) after several updates.
• In seismic series (Granada aftershocks, episodes in Almería or the Canary Islands), it is emphasized that the IGN list “is updated as stations detect and review new events,” and that the number of earthquakes and their parameters may vary during the morning or the following days.

3. Continuous update of the seismic catalog

• This review logic is not limited to the main earthquake: the complete catalog remains in “continuous review” while active seismic sequences last. Each new record can provide additional information justifying small magnitude adjustments in one or more events, or the inclusion of very small earthquakes initially overlooked.
• Official texts emphasize that the National Seismic Network is a permanent monitoring system, and the National Plan for Seismic, Volcanic, and Other Geophysical Phenomena Monitoring approved in 2025 aims to strengthen this capacity, even with tools based on artificial intelligence to improve early warnings. This technological reinforcement aims precisely to make both initial estimates and their subsequent reviews more accurate and faster.

4. From provisional data to “definitive” values

• In practice, several versions of the record follow for the same earthquake: one or more preliminary solutions and, after some time, a stabilized solution considered a reference for technical reports, risk studies, etc.
• Media closely following these episodes expressly record this dynamic: they point out that “the figures disseminated during the first hours have changed as data was reviewed” and that, prudently, it is advisable to always refer to the latest available record from the official seismological organization.
• Consequently, the IGN procedure does not consist of “correcting” isolated errors afterward, but rather a normal refinement process: first, the most probable data is published with the available information; then the magnitude (and other parameters) is updated when analysis with more stations and more time allows a better estimate.

In summary, the IGN follows a scheme of rapid detection + progressive review: the National Seismic Network detects and locates the event, assigns a preliminary magnitude, and from there the seismic catalog remains under continuous review until converging on more precise values, which may differ slightly from the initial ones. This possibility of updating is explicit and part of the normal operation of the official seismic monitoring system in Spain.

In the state civil protection regulations, there is no body literally called the “Advisory Committee of the Seismic Plan”. What the Basic Guideline for Civil Protection Planning against Seismic Risk (approved by Agreement of the Council of Ministers, published by Resolution of May 5, 1995, of the Secretary of State for the Interior, BOE-A-1995-12364) does establish is that, when a relevant seismic emergency occurs, the emergency management body will have the assistance of an Advisory Committee. It is this committee that, in practice, is sometimes colloquially referred to as the “advisory committee of the seismic plan.”

Institutional framework and scope

The Basic Guideline configures a tiered system of special plans against seismic risk (regional and state) and foresees that, when the emergency:

• Is declared of national interest, or
• It is necessary to coordinate the State and the affected autonomous community in a reinforced manner,

a Steering Committee is established, operating through an Integrated Operational Coordination Center (CECOPI). This Steering Committee is formed, at minimum, by:

• A representative of the Ministry of Justice and Interior (today, Interior).
• A representative of the affected autonomous community.

And the Guideline itself expressly indicates that this Steering Committee will have, “for the performance of its functions, the assistance of an Advisory Committee and an Information Office.”

Competencies of the Advisory Committee

The Guideline does not develop a detailed catalog of functions but clearly allows deducing the nature of the Advisory Committee:

• It is a technical support and coordination body for the Steering Committee within the framework of a seismic emergency.
• Its main role is to provide specialized criteria for evaluating the situation, forecasting the evolution of the phenomenon, and proposing intervention measures.
• It facilitates the integration of information from the different services and administrations involved (civil protection, health emergencies, security, technical services, etc.) so that the Steering Committee can adopt coherent operational decisions.
• It contributes to ensuring coherence between the state plan and the regional plans against seismic risk, especially when the national interest of the emergency has been declared and additional state resources must be mobilized.
• It may participate in the definition of action priorities (rescue, evacuations, protection of critical infrastructures, restoration of basic services) based on available data on damage and risks.

In summary, it is not a final decision-making body—that responsibility lies with the Steering Committee—but a multidisciplinary technical advisory structure that feeds information and analysis to the plan management decisions.

Composition and members

The Basic Guideline defines the composition of the Advisory Committee in an open and flexible way. The legal text literally states that:

“The Advisory Committee will include representatives of the bodies of the different Administrations, as well as the technicians and experts that the Steering Committee considers necessary in each case.”

From this formulation, several key ideas emerge:

• There is no closed list of members in the state regulation; the composition adapts to the type of emergency and the affected territory.
• Administrations with relevant competencies in crisis management must be represented: General State Administration, affected autonomous community or communities, and, where appropriate, local entities through their civil protection and emergency services.
• The incorporation of technicians and experts (for example, specialists in seismology, geotechnics, construction, infrastructures, essential services, etc.) is expressly foreseen, designated according to the specific needs of each seismic episode.
• The decision on which experts and bodies are incorporated is made by the Steering Committee itself, allowing the size and profile of the Advisory Committee to be adjusted according to the severity, location, and characteristics of the earthquake.

Practical summary

In conclusion, under the colloquial name “Advisory Committee of the Seismic Plan,” reference is actually made to the Advisory Committee provided for in the Basic Guideline for Civil Protection against Seismic Risk, which:

• Is activated as a body of technical support and coordination to the Steering Committee of the seismic emergency, within the CECOPI.
• Has the fundamental mission to advise on risk assessment, prioritization of actions, and resource coordination.
• Is composed of representatives of the different administrative levels involved and the technicians and experts that the Steering Committee deems necessary in each case, without predetermined composition in the state regulation.

In current regulations, there is no single numerical threshold (for example, “from intensity X on the Richter scale”) that automatically requires all buildings in Granada to be inspected after an earthquake. What exists is a set of state and Andalusian civil protection and construction rules that, combined, establish when a building must be inspected and who can order that inspection.

State framework: seismic-resistant standards and civil protection

At the state level, earthquake safety is basically articulated on two levels:

• Seismic-resistant construction standard: general part and building (NCSR‑02), approved by the Royal Decree 997/2002. It establishes the conditions that structures must meet “so that their behavior, in the face of seismic phenomena, avoids serious consequences for the health and safety of people, avoids economic losses, and promotes the conservation of basic services for society in cases of high-intensity earthquakes.” It regulates how buildings are designed and constructed in seismic zones (Granada is among them), but does not set a detailed protocol for “post-earthquake inspection” building by building.
• The Basic Guideline for Civil Protection Planning against Seismic Risk, approved by Resolution of May 5, 1995 and subsequently modified, which guides state and regional plans. In its section 2.4.3, among the “measures related to buildings,” it expressly foresees:
  • Debris removal.
  • Inspection and classification of buildings according to their condition and hazard.
  • Reinforcement or demolition of damaged buildings.
  That is, it requires that, once an earthquake causes damage, an inspection and classification campaign of the affected buildings be organized.

Additionally, the State Civil Protection Plan against Seismic Risk, approved by Resolution of March 29, 2010, operationally develops this Guideline, but does so at the state level (activation levels, coordination, etc.), without detailing when a specific property in Granada must be inspected.

Andalusian regulations and the role of plans

At the regional level, the basic piece is the Law 2/2002, of November 11, on Emergency Management in Andalusia (BOE-A-2002-24156). This law:

• Defines the Andalusian civil protection system and the territorial and municipal emergency plans.
• Empowers civil protection authorities to order evacuations, restrict access, and conduct inspections in situations of serious risk, catastrophe, or public calamity (initial articles of Title II).
• Requires that there be a Territorial Emergency Plan of Andalusia and municipal plans integrated into it, which specify damage assessment and rehabilitation procedures, including buildings.

The law does not set rigid seismic intensity or damage thresholds for each building but refers to these plans and the technical assessment of the competent services. The recent Decree 197/2024, of September 3, regulating the Local Civil Protection System in Andalusian municipalities (BOJA 174/2024) reinforces this scheme but also does not introduce specific numerical criteria for post-seismic inspections; rather, it organizes the local system (groups, municipal plans, etc.).

Specific situation in Granada

In the consulted databases, there is no municipal ordinance of Granada that sets, for example, “from acceleration X all buildings will be inspected.” What operates in practice is:

• The inclusion of Granada in the seismic hazard zone of NCSR‑02, which affects building design and their expected vulnerability.
• The general obligation, derived from the state Basic Guideline (2.4.3), to inspect and classify damaged buildings when an earthquake causes appreciable damage.
• The competencies of the Junta de Andalucía and the City Council, under Law 2/2002, to:
  • Activate the Territorial Emergency Plan of Andalusia and the municipal emergency plan of Granada.
  • Order technical inspections of buildings that:
    • Show visible damage (significant cracks, deformations, falling elements, etc.).
    • House especially sensitive uses (health centers, educational centers, essential facilities).
    • Are considered “elements at risk” in risk maps prepared according to Law 2/2002.

Practical requirements that trigger the inspection

In summary, in Granada a building will be subject to inspection after an earthquake when, essentially, these elements concur:

• The earthquake produces damage or signs of damage in the building or its immediate surroundings.
• The intensity of the earthquake and its location lead civil protection to activate the emergency plan and schedule campaigns of inspection and classification of buildings, following the 1995 Basic Guideline.
• The municipal or Junta technical services consider that the building is part of the “elements at risk” whose destruction could cause casualties or interrupt essential services, according to the Basic Guideline and regional planning.
• The competent authority (usually the mayor, through the municipal plan, or the Junta in more serious scenarios) issues inspection or use limitation orders, supported by Law 2/2002.

In the absence of a municipal ordinance with its own numerical thresholds, the applicable criterion in Granada is, therefore, the general civil protection one: any building that shows damage or can reasonably be considered at risk after an earthquake must be inspected and classified by technical services, within the actions foreseen in the state, regional, and municipal emergency plans.