The Philippines sits at the intersection of several major tectonic plates, making it one of the most seismically and volcanically active countries in the world. Located on the Pacific Ring of Fire, the archipelago is home to around 300 volcanoes, 24 of which are considered active. The Philippines is regularly struck by earthquakes, with the Philippine Institute of Volcanology and Seismology (PHIVOLCS) recording an average of 30 earthquakes per day. Beyond seismic events, many urban areas across the archipelago face a quieter but no less significant threat: gradual ground subsidence driven by groundwater extraction, soil compaction, and the natural settling of soft sediments beneath rapidly expanding cities.
These slow and often invisible movements can have serious consequences for infrastructure, communities, and agriculture. The ability to detect, map, and monitor ground motion at scale is therefore critical for land use planning, disaster risk reduction, and the long-term protection of public safety across the Philippines.
The CopPhil Ground Motion Monitoring Service (GMMS) has been developed to support Philippine institutions in leveraging Copernicus satellite data for this purpose. This article explores the service products co-developed with local stakeholders, and how they can benefit decision-makers across government.
Copernicus for Ground Motion Monitoring
Copernicus, the Earth Observation component of the EU Space Programme, plays a key role in global ground motion monitoring, providing free and open data useful for the detection of changes on the Earth’s surface. A major contribution comes from the Sentinel-1 satellites, which use Synthetic Aperture Radar (SAR), a technology that measures how the radar signal emitted from the instrument is reflected by the Earth’s surface and received back by the satellite. By comparing radar images acquired at different times, scientists can generate interferograms, revealing subtle changes in the phase of the radar signal caused by surface movement. This method, called Interferometric SAR (InSAR), makes it possible to monitor processes such as subsidence, landslides, earthquakes, and volcanic activity with millimetric to sub-millimetric precision, regardless of cloud cover or daylight.
The CopPhil Ground Motion Monitoring Service
The CopPhil GMMS generates three complementary products, each designed to serve different technical requirements and user needs.
The GMMS Basic Product provides line-of-sight (LoS) velocity maps in ascending and descending orbits, annotated with geolocation and quality measures for each measurement point. Referenced to a local reference point, this product forms the foundational layer of the service, providing systematic coverage of ground motion patterns and enabling first-level analysis of areas of concern.
The Calibrated Product builds on the Basic product by referencing line-of-sight velocity maps to a model derived from Global Navigation Satellite System (GNSS) time-series data. This calibration step removes systematic biases present in the radar measurements, resulting in more accurate and physically interpretable velocity fields. For applications requiring precise quantification of ground motion, such as monitoring critical infrastructure, the Calibrated product provides a significantly improved level of reliability.
The Ortho Product takes the analysis a step further by combining the Calibrated ascending and descending products to retrieve true three-dimensional components of motion, specifically horizontal East-West and vertical Up-Down displacement. By decomposing line-of-sight measurements into their directional components, the Ortho product allows users to distinguish between vertical subsidence and lateral ground movement, which is particularly relevant for interpreting the behaviour of slopes, fault zones, and urbanised areas subject to differential settling.
Example of the GMMS Ortho Product showing East-West motion (left) and Up-Down motion (right) for a selected area of Luzon.
Together, these three products provide a suite of outputs which can be tailored to the needs of different agencies and applications, from broad hazard screening to site-specific engineering assessments.
Building National Capacity for Ground Motion Analysis
The Ground Motion Monitoring Service has been co-developed in close coordination with Philippine partner institutions. Validation of CopPhil products has drawn on ground truth data from the National Mapping and Resource Information Authority (NAMRIA), which provides GNSS-derived reference measurements essential for calibrating satellite observations. This collaboration has strengthened the reliability of the products and helped ensure they are grounded in the Philippine institutional context.
As of early 2026, the service has achieved a significant milestone, with CopPhil ground motion maps now covering over 50% of the Philippines. This represents a major step forward in providing Philippine authorities with consistent, satellite-derived ground deformation data at national scale.
The urgency of ground motion monitoring in the Philippines is increasingly reflected at the international level. In April 2026, CopPhil will participate in the First International Land Subsidence Symposium in Manila, centred around the theme of developing a common strategy for land subsidence in the northern Manila Bay area: a region where subsidence rates exceed 10 cm per year in some locations, with serious consequences for flooding and tidal inundation. Organised by the National Engineering Center at UP Diliman and Wageningen University & Research, the symposium will bring together scientists, practitioners, and decision-makers to exchange knowledge and advance science-based solutions. The products and maps produced by the GMMS offer the kind of consistent, regularly updated baseline that science-based strategies for areas like North Manila Bay call for.
Operationalising the service has also involved navigating real technical challenges. Processing the large volumes of Copernicus Sentinel-1 data required for nationwide coverage demands substantial computational infrastructure, and PhilSA is developing the platform capacity needed to support sustained operations. Dedicated workshops are also being developed to support agency users in building the background knowledge needed to work with these products effectively.
The CopPhil GMMS has been developed and delivered alongside CopPhil’s other thematic services on Land Cover, Forest and Crop Mapping and Benthic Habitat Monitoring. As mainstreaming activities progress in 2026, the service will be increasingly integrated into the workflows of key agencies including PHIVOLCS and NAMRIA, supporting evidence-based decision-making on infrastructure stability, hazard assessment, and post-disaster response.
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Background Information
As a flagship and unique programme of the EU’s Global Gateway strategy, CopPhil is designed to harness digital resources and space technology for sustainable development and to support innovations in research and business in close cooperation with government partners.
CopPhil is managed by the European Union Delegation to the Philippines. It is implemented by the European Space Agency (ESA) in partnership with the Philippine Space Agency (PhilSA) and the Philippine Department of Science and Technology (DOST). In addition to the development of the Earth Observation Services, the activities of CopPhil include the establishment of a Copernicus Data Centre and IT infrastructure as well as awareness-raising and knowledge and skills transfer related to Copernicus data and information.
