1. Background

On 24 June 2026, the north-central region of Venezuela was affected by a large-magnitude seismic doublet. According to preliminary USGS data, the first event occurred at 22:04:33 UTC, equivalent to 18:04:33 Venezuela local time, with moment magnitude Mw 7.2, an approximate epicentre at 10.436°N, 68.528°W, and a depth of about 20.3 km. Approximately 39 seconds later, the main event occurred with magnitude Mw 7.5 at 22:05:11 UTC, equivalent to 18:05:11 Venezuela local time, with an epicentre at 10.401°N, 68.321°W, and a depth of 10.0 km (USGS, 2026). These events were located west of Caracas, in a tectonically complex region associated with the boundary among the Caribbean Plate, the North Andes Block, and the South American Plate. The regional tectonic context has been documented by previous geological and geodetic studies. Based on GPS observations and seismological data, (Pérez et al. 2018) reported that, east of the Caribbean–South America–North Andes triple junction, near 68°W and 10.7°N, the relative Caribbean–South America motion is predominantly dextral, approximately east-west in orientation, with a rate on the order of 19.6 ± 2.0 mm/yr. This deformation is mainly distributed between the San Sebastián Fault, with a rate close to 17.0 ± 0.5 mm/yr, and the La Victoria Fault, with an approximate rate of 2.6 ± 0.4 mm/yr.

2. GNSS Data and Processing

This preliminary analysis is based on the RINEX files from the continuously operating GNSS station CCS1 (10.489111°N, 66.887779°W, GRS80), located on the campus of the Universidad Central de Venezuela (UCV) in Caracas. The station is part of the national geodetic infrastructure associated with the Red de Monitoreo Satelital Venezolana (REMOS), operated by the Instituto Geográfico de Venezuela “Simón Bolívar” (IGVSB). Observations for 22, 23, 24, 25, and 26 June 2026 were processed using 24-hour sessions and a 30-second sampling interval. The 22 and 23 June solutions were considered representative of the pre-event position, whereas the 25 and 26 June solutions were used as the post-event reference. The 24 June data set, which contains observations before and after the seismic doublet, was assessed with special attention in order to identify the coseismic offset. The processing was carried out through two approaches: Precise Point Positioning (PPP) using the CSRS-PPP service of Natural Resources Canada (NRCan), with rapid orbit products, and, independently and in parallel, processing of the same data using the Online Positioning User Service (OPUS) of the National Geodetic Survey (NOAA/NGS). Static and kinematic solutions were generated, and position differences were expressed in the local DE, DN, and DU system. All GNSS results were referred to ITRF2020 (2026.5), UTM Zone 19N, with an accuracy of ±0.01 m.

3. Preliminary Results

The comparison between the pre- and post-seismic GNSS solutions indicates that station CCS1 experienced a predominantly horizontal coseismic displacement, almost entirely oriented toward the west. All differences were computed with respect to the reference coordinates corresponding to 22 June 2026. The results obtained from CSRS-PPP and OPUS are presented in Table 1. The estimated displacement components were -0.464 m in DE, -0.011 m in DN, and +0.021 m in DU. These values show that the dominant signal corresponds to westward horizontal displacement, whereas the north and vertical components have considerably smaller magnitudes. As a complementary analysis, a kinematic GNSS-PPP processing was performed for 24 June 2026. This solution made it possible to identify an offset in the three components of station CCS1, DLon, DLat, and DAlt, around 2026-06-24 22:05:30.00 UTC, the approximate time of occurrence of the main seismic event (Figure 1). From the kinematic perspective, the vertical component exhibited significant variations after the event, with changes reaching approximately +0.10 m.

                           Table 1. Static GNSS coordinate differences for CCS1, 22-26 June 2026.  

The overall consistency between the static and kinematic solutions, particularly in identifying the offset and its predominant direction, reinforces the interpretation that the observed change corresponds to a real coseismic signal. Nevertheless, the vertical component must be interpreted with caution because it is more sensitive to atmospheric effects, satellite geometry, multipath, monument stability, and the quality of the orbit and clock products used. The magnitude of the estimated horizontal displacement is significantly larger than the expected interseismic deformation for the Caribbean-South America boundary in this region. As a reference, a relative rate on the order of ~2 cm/yr is much smaller than the coseismic displacement observed at CCS1, indicating a sudden, high-amplitude signal compatible with elastic deformation released during the seismic event. This interpretation should be compared with the previously observed regional kinematic regime. In particular, SIRGAS-CON results for station CRCS00VEN, located in Caracas, indicate geodetic velocities of VE = -0.00019 m/yr, VN = +0.01232 m/yr, and VU = -0.00098 m/yr. Consequently, the displacement recorded at CCS1 should be understood as a coseismic signal superimposed on the regional interseismic regime described by the available kinematic and crustal-deformation models, including VEMOS2022 and APKIM2020 (Drewes et al., 2024).

4. Preliminary Interpretation

The GNSS results suggest that station CCS1 recorded a significant coseismic displacement associated with the seismic doublet of 24 June 2026. The dominant westward component is consistent with the regional kinematic context, which is characterized by dextral deformation along the fault system of northern Venezuela. However, a definitive tectonic interpretation requires integration of additional GNSS stations, seismic solutions, focal mechanisms, and rupture models. Confirmation requires reprocessing with final products and independent analysis of kinematic time series.

5. Limitations

These results should be considered preliminary for four main reasons. First, rapid products rather than final products were used. Second, the analysis interval covers only five days. Third, the daily solution for 24 June may be affected by the mixing of pre- and post-seismic observations. Fourth, the analysis is initially based on a single station, which limits the separation of regional deformation, local effects, and instrumental uncertainties. It is recommended to verify the station metadata, monument stability, possible antenna or receiver changes, RINEX quality, cycle slips, and local conditions during and after the earthquake.

6. Final Comments

The preliminary processing of GNSS station CCS1 indicates a horizontal coseismic displacement of approximately 0.464 m, directed mainly toward the west, and 0.011 m toward the south, accompanied by a positive vertical component of about +0.021 m. This signal constitutes initial geodetic evidence of significant deformation in Caracas associated with the seismic doublet that occurred on 24 June 2026. Nevertheless, these results should be considered preliminary. The estimate should be refined through reprocessing of the GNSS data using final orbit and clock products, temporal segmentation of the RINEX file for 24 June, incorporation of additional GNSS stations, and comparison with seismic, geological, and InSAR models. These steps will improve the robustness of the estimate, assess its spatial coherence, and reduce possible local or instrumental effects. InSAR processing over the affected area is currently underway. Those results will provide complementary regional spatial information on the deformation field and will allow the signal detected at GNSS station CCS1 to be independently evaluated. Until these additional analyses are available, the reported values should be interpreted as a first geodetic approximation of the impact of the seismic event in the Caracas region.

7. References

• Drewes, H., Seitz, M., Sánchez, L. (2024). Realisation of the Non-Rotating Terrestrial Reference Frame by an Actual Plate Kinematic and Crustal Deformation Model (APKIM2020). International Association of Geodesy Symposia. https://doi.org/10.1007/1345_2024_276
• IGVSB – Instituto Geográfico de Venezuela “Simón Bolívar”. (2026). Red de Monitoreo Satelital Venezolana (REMOS): reference frame and metadata for station CCS1, Caracas.
• Online Positioning User Service (OPUS), National Geodetic Survey, USA (NOAA/NGS).
• Natural Resources Canada (NRCan). Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP). webapp.csrs-scrs.nrcan-rncan.gc.ca/
• Pérez, O., Wesnousky, S., De La Rosa, R., Márquez J., Uzcátegui, R., Quintero, C., Liberal, L., Mora-Páez, H., Szeliga, W. (2018). On the interaction of the North Andes plate with the Caribbean and South American plates in northwestern South America from GPS geodesy and seismic data. Geophysical Journal International. https://doi.org/10.1093/gji/ggy230
• SIRGAS – Geocentric Reference System for the Americas. (2024). VEMOS velocity model / VEMOS2022: South American and Caribbean velocity field based on APKIM2020.
• USGS – United States Geological Survey. (2026). Earthquake Catalog: Venezuela doublet earthquake sequence, 24 June 2026.

8. Acknowledgements

The authors thank the Instituto Geográfico de Venezuela “Simón Bolívar” (IGVSB) for providing the GNSS data from the REMOS network; the CSRS-PPP service of Natural Resources Canada (NRCan) and the OPUS service of the U.S. National Geodetic Survey (NOAA/NGS) for processing the GNSS observations; the Geocentric Reference System for the Americas (SIRGAS) for reference-frame products and velocity models; and the United States Geological Survey (USGS) for access to the preliminary seismic catalog.