A magnitude 3.6 earthquake shakes Almería and has its epicenter in Antas.

After an earthquake, the National Geographic Institute (IGN), through the National Seismic Network, follows a chain of actions that combine automatic recording, expert review, and updating of public and official information. The goal is to provide increasingly accurate data on the location, magnitude, and impacts of the earthquake, and to feed alert systems and emergency planning.

1. Automatic detection and initial recording

The basis of the system is the monitoring networks managed by the IGN. The National Plan for Seismic, Volcanological, and Other Geophysical Phenomena Monitoring, approved by the Council of Ministers for 2025‑2028 and developed by the IGN itself, establishes that these networks will be reinforced and densified to improve rapid detection of earthquakes and other geophysical phenomena (Transport Press Release).

When a seismic event occurs, the seismic stations of the National Seismic Network send the records to the IGN data center in (almost) real time. With these initial instrumental data, a preliminary solution is automatically calculated:

• Hypocenter (depth and coordinates).
• Preliminary magnitude.
• Origin time of the earthquake.

This preliminary information feeds services such as IGN Earthquakes, an application that the National Geographic Information Center presents as a public viewer of seismic activity recorded by the IGN (CNIG applications).

2. Review and refinement of seismic parameters

The first solution is rarely definitive. The National Plan itself indicates that it aims to “advance knowledge and research” to improve forecasts and information quality, and that tools—including Artificial Intelligence—will be deployed to make monitoring and early warning systems more effective (MITMA, 3/4/2025). In practice, this translates into:

• Progressive incorporation of more stations (including regional or international networks) into calculations, allowing location refinement.
• Use of advanced processing algorithms and increasingly AI techniques to distinguish useful signal from noise and adjust magnitudes.
• Expert review by seismologists, who contrast automatic results with prior knowledge of the area, ongoing seismic sequences, etc.

As more seismic phases are confirmed and records validated, the IGN updates the event parameters in its databases and public viewer. Hence, in the first minutes, magnitude or depth figures may change slightly, something the press also commonly reports for other seismic services.

3. Updating catalogs and alert systems

The IGN's work is not limited to an isolated earthquake: it maintains historical catalogs and hazard maps used for emergency planning and regulations. The National Plan sets 58 measures to strengthen networks and improve both immediate response and medium- and long-term analyses, so that each new event is incorporated into:

• The official earthquake catalog in Spain and nearby areas.
• Hazard and seismic risk studies by area.
• Specific alert systems (for example, the National Tsunami Warning System, where the National Seismic Network is the body that detects, assesses, and initially reports events that may generate tsunamis, according to the IGN‑SOCIB agreement published in the Official State Gazette BOE‑A‑2025‑22841).

In parallel, the IGN provides standardized information to Civil Protection and other competent bodies, which integrate it into their special seismic risk plans (state and regional) to support emergency management decisions.

4. Continuous improvement and institutional cooperation

Official documents highlight that the system operates within a framework of continuous improvement and cooperation. Fifty-four academic, scientific-technical entities, and public administrations participated in the development of the National Plan to coordinate networks, share data, and strengthen response capacity to seismic-volcanic crises.

Additionally, specific agreements—such as the one with SOCIB for tsunamis or agreements with universities—strengthen technical capabilities (new sensors, real-time transmission, model development) that directly impact the quality and speed with which seismic data are reviewed and updated each time an earthquake occurs.

In summary, after a seismic event, the IGN moves from a preliminary automatic record to a reviewed and validated solution, which is integrated into catalogs and alert systems and made available to authorities and the public through tools like IGN Earthquakes, within a national seismic monitoring and risk reduction strategy.

The National Geographic Institute (IGN), attached to the Ministry of Transport and Sustainable Mobility, is the state reference body in Spain for monitoring seismic activity and other geophysical phenomena. Its competencies in this area are supported by several royal decrees and the development of the National Plan for Seismic, Volcanological, and Other Geophysical Phenomena Monitoring, and are mainly carried out through the management of the National Seismic Network and its role in alert systems, especially for tsunamis.

Regulatory basis of the IGN's competencies

At the organizational level, Royal Decree 253/2024, of March 12, which develops the basic structure of the Ministry of Transport and Sustainable Mobility, assigns to the General Directorate of the IGN, among others, the following functions (included in an agreement published in the Official State Gazette):

• Planning and management of monitoring, communication, and alert systems to institutions against tsunamis that may affect the Spanish coasts, as well as participation in international tsunami alert networks and conducting work and studies on early warning systems and tsunami hazard (text of the agreement).
• Planning and management of geodetic networks and the tide gauge network that are part of the Spanish Geodetic Reference System, including exploitation and analysis of geodetic and geodynamic observations (BOE-A-2025-22841).

In the field of civil protection, Royal Decree 1053/2015, of November 20, which approves the Basic Guideline for Civil Protection Planning against Tsunami Risk, establishes that the National Seismic Network (RSN), dependent on the IGN, is part of the National Tsunami Warning System and defines it as the body:

"responsible for detecting, assessing, and initially reporting those phenomena that, due to their characteristics, could produce tsunamis" (BOE-A-2025-22841, which explicitly cites RD 1053/2015).

Furthermore, the Government tasked the Ministry—through Royal Decree-law 2/2022—with drafting a National Plan for Seismic, Volcanological, and Other Geophysical Phenomena Monitoring, whose development was entrusted to the IGN. According to the ministry's official note (March 4, 2025), the Council of Ministers approved this Plan, which:

• Develops 58 measures to strengthen monitoring and detection networks for earthquakes, volcanic eruptions, tsunamis, and other phenomena.
• Seeks to improve communication and response systems and coordination among administrations.
• Foresees that the National Seismic Network will develop AI-based tools to improve early warnings in case of earthquakes (Ministry of Transport note).

Functions of the IGN in seismic monitoring and the National Seismic Network

Based on this regulatory framework, the IGN's functions in seismic monitoring can be summarized in several blocks:

• Operation of the National Seismic Network (RSN): the IGN is the body that officially records earthquakes in Spain and nearby areas. Various official and press sources describe how the IGN maintains an up-to-date real-time record of seismic events, which serves as a reference for administrations and the public.
• Detection and evaluation of seismic activity: the RSN detects seismic movements, determines parameters such as location, magnitude, and depth, and allows distinguishing between tectonic, volcanic, or other causes of seismicity. This capability is indirectly mentioned when official notes refer to the IGN "detecting" and "recording" earthquakes and that the RSN is the basis for risk monitoring (National Plan).
• Seismic hazard mapping: the IGN maintains seismicity and hazard maps that identify the highest seismic risk areas in Spain (southern and southeastern peninsula, Alboran Sea, Gulf of Cádiz, Pyrenees, Canary Islands, etc.), which are used as references for planning and seismic-resistant regulations (analysis of risk zones).
• Technical support for civil protection planning: in the case of tsunamis, the RSN is the first detection and assessment body within the National Tsunami Warning System (RD 1053/2015). Its analyses serve for civil protection bodies to decide whether to activate emergency measures.
• Development of early warning systems: the National Plan foresees that the RSN incorporates artificial intelligence tools to anticipate earthquake alert issuance by a few seconds, and that different monitoring systems coordinate to “act as one,” improving warning times and reducing risks (official note).
• Scientific and technical cooperation: the IGN signs agreements with universities and other scientific infrastructures to strengthen geophysical observation (for example, sea level monitoring with GNSS buoys as part of the national tsunami warning system), complementing seismic and tsunami monitoring (BOE‑A‑2025‑22841).

Overall, the cited regulations position the IGN as responsible for the State's seismic monitoring network, manager of the National Seismic Network, and a key technical player in alert systems, especially against tsunami risk. Population warnings and operational emergency management correspond to civil protection bodies but rely on the geophysical information continuously provided by the IGN and the RSN.

The response to earthquakes in Andalusia is framed within a tiered system: basic state civil protection regulations and Andalusian-specific emergency management and territorial planning regulations. According to consulted sources, there is no specific Andalusian plan solely for seismic risk published as such, but earthquakes are addressed as one of the risks integrated into territorial and special civil protection plans, supported by the state guideline and plan for seismic risk.

1. Basic state framework for civil protection and seismic risk

• Law 17/2015, of July 9, on the National Civil Protection System (BOE). Defines civil protection as a public service and structures the National Civil Protection System, establishing:
  • The obligation to prevent, plan, intervene, and recover from emergencies.
  • The existence of territorial plans and special plans for specific risks (including seismic risk).
  • Necessary coordination among the State, autonomous communities, and local entities, and their participation in the National Civil Protection Council.
  This law obliges autonomous communities and local entities to have their own planning consistent with the basic regulation and state guidelines.
• Royal Decree 524/2023, of June 20, approving the Basic Civil Protection Standard (BOE). Develops Law 17/2015 and:
  • Establishes the catalog of risks subject to planning.
  • Defines the minimum content of territorial plans, special plans, and self-protection plans.
  • Orders that territorial plans of autonomous communities and local entities integrate the special plans within their scope.
  Although it does not regulate only seismic risk, it is the mandatory reference for how Andalusia and municipalities must plan and coordinate for earthquakes.
• Basic Guideline for Civil Protection Planning against Seismic Risk, approved by Council of Ministers Agreement of April 7, 1995, and published by Resolution of May 5, 1995 (BOE).
  • Orders the preparation of special plans against seismic risk at state, regional, and local levels in seismic hazard zones.
  • Includes all Andalusian provinces as seismic hazard areas.
  • Sets minimum requirements on structure, organization, operational criteria, and coordination mechanisms among state, regional, and local plans.
• State Civil Protection Plan against Seismic Risk, approved by Council of Ministers Agreement of March 26, 2010, and published by Resolution of March 29, 2010 (BOE).
  • Defines the organization and procedures for the State's resources and services in response to earthquakes.
  • Operationally relies on the special and territorial plans of autonomous communities and on local action plans.
  • Provides support mechanisms for regional plans when they require it or lack sufficient capacity.
• Seismic-resistant construction standards, mainly affecting the preventive phase:
  • Royal Decree 997/2002, of September 27, approving the NCSE-02 (general part and building) (BOE).
  • Royal Decree 637/2007, of May 18, approving the seismic-resistant construction standard for bridges (NCSP-07) (BOE).
  They bind administrations in their urban planning and construction control functions, reducing structural vulnerability to earthquakes.

2. Andalusian regulations and obligations of local and regional authorities

• Law 2/2002, of November 11, on Emergency Management in Andalusia (BOE). It is the Andalusian framework law on civil protection and emergencies:
  • Configures the Andalusian civil protection system and the Emergency Coordination Center.
  • Defines emergency plans as the basic regulatory instrument and distinguishes:
    • Territorial emergency plans (including the Andalusian Territorial Emergency Plan and municipal plans).
    • Special and specific plans for risks of “special significance” (including seismic risk in planning practice).
    • Self-protection plans and sectoral plans.
  • Obliges local entities to:
    • Develop and approve municipal territorial emergency plans, homologated by the Andalusian Civil Protection Commission.
    • Integrate their plans with the Andalusian Territorial Emergency Plan and special plans.
    • Provide information on means and resources to the Junta and participate in coordination devices.
  • Obliges the Junta to:
    • Develop the Andalusian Territorial Emergency Plan and special plans (including the one related to seismic risk when appropriate).
    • Lead and coordinate the response at the regional level, except when declared of national interest.
• Andalusian Civil Protection Territorial Emergency Plan (PTEAnd), approved by Decree 69/2024, of March 4, according to the error correction published in the BOJA (BOJA).
  • Acts, according to Law 2/2002 itself, as a master plan: sets guidelines and requirements for all Andalusian emergency plans.
  • Establishes the organic and functional framework for regional and provincial response to major emergencies, including those derived from earthquakes.
  • Is the reference to which municipal plans and special risk plans must adapt.

3. Summary of specific obligations regarding earthquakes

• Junta de Andalucía: must plan (PTEAnd and special plans), coordinate operational services, and support and homologate municipal plans, in coherence with Law 17/2015, the Basic Civil Protection Standard, and the Seismic Guideline.
• Andalusian local entities: must approve municipal territorial emergency plans, foresee local activation and management in case of earthquakes, and ensure integration with regional and state plans.
• Coordination with the State: when the emergency is declared of national interest, the State Seismic Risk Plan applies and the integrated management committee and coordination center scheme described in the 2010 plan is activated.