The Tequila volcano is located on the northeastern margin of the Jalisco Block, along the Tepic-Zacoalco rift in western Mexico, and its latest activity has been dated at approximately 90 ka. In this study, we use the GGMplus gravity data set to perform 3D gravity inversions to depths of up to 8 km from the surface to explore the possible location of the two magma storage regions previously proposed for Tequila volcano. During the inversion process, models with 1000 and 250 m resolution were evaluated to image the magmatic plumbing system beneath the main volcanic edifice and the adjacent lava flows. The 1000 m resolution model reveals a shallow low-density region at about +500 masl beneath Tequila volcano, as well as a deeper anomaly located about 8 km southeast of the summit, at approximately ？6000 mbsl; the locations of these anomalies match the location of previously positioned magma chambers proposed for this volcanic system. The inversion results also suggest a structurally controlled zone that may have facilitated magma ascent, including a narrow connection near ？3300 mbsl between both low-density regions. The 250 m resolution model further resolves a bifurcation of the shallow low-density region beneath the summit depression, a geometry that may help explain the origin of the summit’s caldera-like morphology and its relation to the central spine. One possible interpretation is that the spine partially obstructed an earlier ascent pathway, promoting a change in the position of eruptive discharge and the development of a lateral conduit; the inferred traces of these possible pathways are illustrated here. The study area also includes the segment of the Santiago River closest to Tequila volcano, which trends NW; in this sector, the inversion identifies shallow low-density materials that may be related to sediment accumulation, as well as a narrow vertical feature extending to ~4100 mbsl, tentatively interpreted as a fault zone.
References
[1]
Vázquez-Duarte, A., Gómez-Tuena, A. and Díaz-Bravo, B. (2011) Igneous Petrogenesis of Tequila Volcano, Western Mexico. American Geophysical Union, Fall Meeting 2011, San Francisco, 5-9 December 2011, Abstract ID V43C-2590.
[2]
Ferrari, L., Petrone, C. M., Francalanci, L., Tagami, T., Eguchi, M., Conticelli, S., Manetti, P. and Venegas-Salgado, S. (2003) Geology of the San Pedro-Ceboruco Graben, Western Trans-Mexican Volcanic Belt. Revista Mexicana de Ciencias Geológicas, 20, 165-181.
[3]
Mahood, G.A. (1980) Geological Evolution of a Pleistocene Rhyolitic Center—Sierra La Primavera, Jalisco, México. Journal of Volcanology and Geothermal Research, 8, 199-230. https://doi.org/10.1016/0377-0273(80)90105-5
[4]
Mahood, G.A. (1981) A Summary of the Geology and Petrology of the Sierra La Primavera, Jalisco, Mexico. Journal of Geophysical Research: Solid Earth, 86, 10137-10152. https://doi.org/10.1029/jb086ib11p10137
[5]
Mahood, G.A. (1981) Chemical Evolution of a Pleistocene Rhyolitic Center: Sierra La Primavera, Jalisco, Mexico. Contributions to Mineralogy and Petrology, 77, 129-149. https://doi.org/10.1007/bf00636517
[6]
Harris, J.M. (1986) Silicic Volcanics of Volcan Tequila, Jalisco, Mexico. MSc Thesis, University of California.
[7]
Wopat, M.A. (1990) Quaternary Alkaline Volcanism and Tectonics in the Mexican Volcanic Belt near Tequila, Jalisco, Southwestern Mexico. PhD Dissertation, University of California.
[8]
Wallace, P.J. and Carmichael, I.S.E. (1994) Petrology of Volcan Tequila, Jalisco, Mexico: Disequilibrium Phenocryst Assemblages and Evolution of the Subvolcanic Magma System. Contributions to Mineralogy and Petrology, 117, 345-361. https://doi.org/10.1007/bf00307270
[9]
Luhr, J.F. and Prestegaard, K.L. (1988) Caldera Formation at Volcán Colima, Mexico, by a Large Holocene Volcanic Debris Avalanche. Journal of Volcanology and Geothermal Research, 35, 335-348. https://doi.org/10.1016/0377-0273(88)90027-3
[10]
Stoopes, G.R. and Sheridan, M.F. (1992) Giant Debris Avalanches from the Colima Volcanic Complex, Mexico: Implications for Long-Runout Landslides (> 100 km) and Hazard Assessment. Geology, 20, Article No. 299. https://doi.org/10.1130/0091-7613(1992)020<0299:gdaftc>2.3.co;2
[11]
Luhr, J.F. (1978) Factors Controlling the Evolution of the Prehistoric, Pyroclastic Eruption of Volcan San Juan. Geological Society of America Abstracts with Programs, 10, 114.
[12]
Nelson, S.A. (1980) Geology and Petrology of Volcan Ceboruco, Nayarit, Mexico. GSA Bulletin, 91, 2290-2431. https://doi.org/10.1130/gsab-p2-91-2290
[13]
Demant, A. (1979) Vulcanología y petrografía del sector occidental del Eje Neovolcánico. Revista Mexicana de Ciencias Geológicas, 3, 39-57.
[14]
Lewis-Kenedi, C.B., Lange, R.A., Hall, C.M. and Delgado-Granados, H. (2005) The Eruptive History of the Tequila Volcanic Field, Western Mexico: Ages, Volumes, and Relative Proportions of Lava Types. Bulletin of Volcanology, 67, 391-414. https://doi.org/10.1007/s00445-004-0377-3
[15]
Alvarez, R. and Camacho-Ascanio, M. (2025) Gravimetric Definition of the Magmatic Chambers of the Popocatépetl-Iztaccíhuatl Volcanic Complex, Mexico. Earth Science and Engineering, 4, 1-18. https://doi.org/10.57237/j.earth.2025.01.001
[16]
Alvarez, R. and Camacho-Ascanio, M. (2026) Two Magmatic Chambers beneath Iztaccíhuatl Volcano Revealed by 3D Gravity Modeling. Academia Earth and Planetary Science, 1, 1-18. https://doi.org/10.20935/acadeps8344
[17]
Kozono, T. (2021) The Dynamics of Dual-Magma-Chamber System during Volcanic Eruptions Inferred from Physical Modeling. Earth, Planets and Space, 73, Article No. 139. https://doi.org/10.1186/s40623-021-01421-4
[18]
U.S. Geological Survey (2026) How Big Is the Magma Chamber under Yellowstone? U.S. Geological Survey. https://www.usgs.gov/faqs/how-big-magma-chamber-under-yellowstone
[19]
Ryan, W.B.F., Carbotte, S.M., Coplan, J.O., O’Hara, S., Melkonian, A., Arko, R., et al. (2009) Global Multi-Resolution Topography Synthesis. Geochemistry, Geophysics, Geosystems, 10, Q03014. https://doi.org/10.1029/2008gc002332
[20]
Camacho, M. and Alvarez, R. (2020) Gravimetric Analysis of the Rifts and Volcanic Fields of the Jalisco Block, Mexico. Tectonophysics, 791, Article ID: 228577. https://doi.org/10.1016/j.tecto.2020.228577
[21]
Camacho, M. and Alvarez, R. (2021) Geophysical Modeling with Satellite Gravity Data: Eigen-6C4 vs. GGM Plus. Engineering, 13, 690-706. https://doi.org/10.4236/eng.2021.1312050
[22]
Alvarez, R. and Camacho, M. (2023) Plumbing System of Hunga Tonga Hunga Ha’apai Volcano. Journal of Earth Science, 34, 706-716. https://doi.org/10.1007/s12583-022-1792-0
[23]
Alvarez, R. and Camacho, M. (2023) Applying High-Resolution Gravity Analysis to Volcanic Plumbing Systems: The Case of Nevado De Toluca Volcano, Mexico. Transactions on Engineering and Computing Sciences, 11, 184-207.
[24]
Alvarez, R., Camacho, M. and Rivera-Calderón, E. (2024) The Internal Structure of Paricutin and Tancítaro Volcanos, Mexico, from Rock Density Distributions. Transactions on Engineering and Computing Sciences, 12, 50-69.
[25]
Camacho-Ascanio, M. and Alvarez, R. (2024) Delineation of the Boundaries of San Blas Basin, Mexico, Merging Gravity, Magnetic, and Seismic Data. Journal of South American Earth Sciences, 136, Article ID: 104818. https://doi.org/10.1016/j.jsames.2024.104818
[26]
Guevara-Betancourt, R., Yutsis, V., Varley, N., Almaguer, J., Alvarez, R., Calderón-Moctezuma, A., et al. (2023) Insights into the Plumbing System of Colima Volcanic Complex from Geophysical Evidence. Journal of Volcanology and Geothermal Research, 433, Article ID: 107711. https://doi.org/10.1016/j.jvolgeores.2022.107711
[27]
GEBCO Bathymetric Compilation Group (2021) The GEBCO_2021 Grid: A Continuous Terrain Model of the Global Oceans and Land. British Oceanographic Data Centre.
[28]
Uz, M. and Ince, E.S. (2025) Retrieving Complete Spherical Bouguer and Isostatic Gravity Anomalies Using Global Gravity Forward Models. Geophysical Journal International, 244, 1-18. https://doi.org/10.1093/gji/ggaf473
[29]
Kane, M.F. (1962) A Comprehensive System of Terrain Corrections Using a Digital Computer. Geophysics, 27, 455-462. https://doi.org/10.1190/1.1439044
[30]
Nagy, D. (1966) The Gravitational Attraction of a Right Rectangular Prism. Geophysics, 31, 362-371. https://doi.org/10.1190/1.1439779
[31]
Alvarez, R. and Yutsis, V. (2015) Southward Migration of Magmatic Activity in the Colima Volcanic Complex, Mexico: An Ongoing Process. International Journal of Geosciences, 6, 1077-1099. https://doi.org/10.4236/ijg.2015.69085
[32]
Suryanata, P.B., Bijaksana, S., Dahrin, D., Nugraha, A.D., Harlianti, U., Putra, P.R.A., et al. (2024) Subsurface Structure of Bali Island Inferred from Magnetic and Gravity Modeling: New Insights into Volcanic Activity and Migration of Volcanic Centers. International Journal of Earth Sciences, 113, 523-538. https://doi.org/10.1007/s00531-024-02398-7
[33]
MacLeod, I.N. and Ellis, R.G. (2013) Magnetic Vector Inversion, a Simple Approach to the Challenge of Varying Direction of Rock Magnetization. Proceedings of the 23rd International Geophysical Conference and Exhibition (ASEG), Melbourne, 11-14 August 2013.
[34]
Elllis, R.G., de Wet, B. and Macleod, I.N. (2012) Inversion of Magnetic Data from Remanent and Induced Sources. ASEG Extended Abstracts, 2012, 1-4. https://doi.org/10.1071/aseg2012ab117
[35]
Ingram, D.M., Causon, D.M. and Mingham, C.G. (2003) Developments in Cartesian Cut Cell Methods. Mathematics and Computers in Simulation, 61, 561-572. https://doi.org/10.1016/s0378-4754(02)00107-6
[36]
Hirt, C., Claessens, S., Fecher, T., Kuhn, M., Pail, R. and Rexer, M. (2013) New Ultrahigh-Resolution Picture of Earth’s Gravity Field. Geophysical Research Letters, 40, 4279-4283. https://doi.org/10.1002/grl.50838
