Imaging the Ceboruco Volcano, Nayarit, Mexico, using the 3D inversion of aeromagnetic data
Zaky Sawires, Rashad Feriz
Nuñez Cornu, Francisco Javier
Martínez-Díaz, Edgar Alan
Metadata:Show full item record
Ceboruco volcano is considered as one of the largest volcanoes of the Trans-Mexican Volcanic Belt that extends along the central-southern parts of Mexico. Few geophysical surveys have been published recently with the aim of studying the internal structure of its magma chamber. In the current work and throughout the support of the CEMIEGeo-P24 geothermal exploration project, the main aims were to delineate the possible subsurface structural trends, to determine the approximate depth to the basement surface, and to provide an illustrative 3D model for its magma chamber. To achieve such goals, a detailed analysis for the aeromagnetic data (after the Mexican Geological Service) for the volcano site was conducted. The processing included: i) reducing the total intensity aeromagnetic values to the north magnetic pole; ii) isolation of the data into their various components (residual and regional); iii) delineation of the possible structural trends using analytical signal and tilt derivative methods, and iv) depth estimation of the defined subsurface structure using 3D inverse modeling. This work represents a preliminary investigation for the project area, which will be succeeded by a detailed ground magnetic and magneto-telluric surveys for the interested anomalies. The total intensity aeromagnetic map reveals higher magnetic elliptical to elongated anomalies concentrated mainly on the middle and to the southern and the southwestern parts of the mapped area. However, elongated lower magnetic anomalies trending mainly on the NW–SE direction are clearly observed on the northeastern parts of the mapped region, which correlates very well with the Tepic Zacoalco rift. The data was inverted assuming four subsurface layers (250, 500, 750 and 1000 m.) using the GMSYS-3D software. From the inversion results, it appears that the boundary of the volcano can be traced easily from the first subsurface layer. A secondary structure line appears towards the east from the volcano boundary and it can be observed from the inversion of the second and third layers. This indicates that both of the base of the volcano and the structure line are from the same source. Finally, they disappeared in the inversion results for the last layer, which concludes that we reached the basement above which the volcano is formed.