32-6 Ground Deformation Signals from a Mw 7.0 Earthquake in the Central Gulf of California

Session: Recent Advances in the Gulf of California Oblique Rift: Offshore and Onshore Studies // Avances Recientes en el Rift Oblicuo del Golfo de California: Estudios Marinos y Terrestres (Part II)

Presenting Author:

Carlos Reinoza

Authors:

Reinoza, Carlos E.¹, Sarychikhina, Olga², Ramón, Elvia³, Pousse-Beltran, Léa⁴, Navarro, Andrés⁵, Yegres, Luis A.⁶, Audemard , Franck A.⁷

(1) Seismology, CICESE, Ensenada, México, Mexico, (2) CICESE, Ensenada, Baja California, Mexico, (3) Seismology, CICESE, Ensenada, Baja California, Mexico, (4) IRD, Université Grenoble Alpes, Grenoble, Isere, France, (5) Seismology, CICESE, Ensenada, Baja California, Mexico, (6) Seismology, CICESE, Ensenada, Baja California, Mexico, (7) Escuela de Geología, Minas y Geofísica, Universidad Central de Venezuela, Caracas, Venezuela, RB; Earth Sciences Division, CICESE, Ensenada, Baja California, Mexico,

Abstract:

Since late 2022, we have revisited some Global Positioning System (GPS) observation sites in the central part of the Baja California Peninsula that were measured previously in 2009. The new GPS campaigns aimed to calculate the displacement rates (mm yr^-1) for each of these sites and to address questions regarding the deformation of the so-called “Baja California Microplate” (BCM) in this area. The combined analysis of the processed 2009 and 2022 datasets reveals a decreasing NE–SW displacement gradient across five sites arranged along a westward profile perpendicular to the Salsipuedes fault (Guaymas fault system). Although previous studies have indicated that 90% of the relative motion between the North American and Pacific plates is accommodated by faults within the Gulf of California, and that internal deformation has been observed at sites closest to these faults (Plattner et al., 2015), the velocity values obtained at sites closest to the Salsipuedes fault are significantly higher than expected. To explain this deformation, we explored the seismic catalog and identified a Mw 7.0 earthquake that occurred in the study area on April 12, 2012. To assess a possible correlation between the seismic event and the observed ground deformation, we applied the InSAR technique using Radarsat-2 SLC W3 images from ascending orbital pass. Six resulting interferograms spanning 1.1–1.3 years, and encompassing the April 12, 2012, Mw 7.0 seismic event, reveal line-of-sight (LOS) ground displacement of up to ~15 cm, concentrated near Punta Ánimas, the peninsula sector closest to the earthquake epicenter. Our GPS and InSAR data provide evidence that the 2012 earthquake may have generated coseismic and possibly postseismic displacement, affecting nearby localities.

Geological Society of America Abstracts with Programs. Vol. 58, No. 3, 2026

© Copyright 2026 The Geological Society of America (GSA), all rights reserved.