32 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)

This session highlights recent research on the Gulf of California–Salton Trough plate boundary from ~12 Ma to today. We welcome terrestrial and marine studies involving tectonics, basin analysis, volcanology, sedimentology, and more. English or Spanish.

Friday, 24 April 2026
8:00 AM - 12:00 PM
LMH, Fiesta Terrace Salon

Shallow Subsurface Structure of the Sudoeste Volcano, San Quintín Volcanic Field, Baja California, from Ambient Seismic Noise

Paper number: 32-11
Program: Technical Sessions
Time: 11:40 AM – 12:00 PM

Authors

Abstract

The San Quintín Volcanic Field (SQVF) is located along the western Pacific margin of the Baja California Peninsula and comprises a set of Quaternary monogenetic cones whose eruptive and structural evolution remains only partially constrained. This study focuses on the Late Pleistocene Sudoeste Volcano to investigate its shallow subsurface structure and evaluate how pre-existing crustal features influence magma ascent and conduit emplacement. Ambient seismic noise data were acquired along two orthogonal profiles across the Sudoeste cone and analyzed using the Horizontal-to-Vertical Spectral Ratio (HVSR) method combined with 1D shear-wave velocity (Vs) inversion. The resulting models reveal a vertically coherent high-Vs anomaly (>2700 m/s) extending from approximately 200 to 800 m depth. This anomaly exhibits a consistent NW–SE elongation that aligns with the surface distribution of nearby monogenetic cones, including Pescador 1 and 2. The high-Vs body is interpreted as a shallow, consolidated intrusive structure, whereas surrounding low Vs values (<800 m/s) likely correspond to unconsolidated volcanic deposits and saturated sediments. These results support the presence of a structurally guided feeder system and highlight the role of inherited crustal discontinuities in controlling magma transport beneath the Sudoeste Volcano. Our findings provide new constraints on the shallow magmatic architecture of monogenetic volcanic systems along the Pacific margin of Baja California and demonstrate the effectiveness of HVSR-based shear-wave velocity models for imaging volcanic subsurface structures.

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

doi: 10.1130/abs/2026CD-410994

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