Internal structure of the southern and central Colima Volcanic Complex, western Mexico, revealed by 3D modeling of aeromagnetic data

Abstract

We present the results of an aeromagnetic survey performed over the central Colima Volcanic Complex situated in the western region of Mexico. Within the interpolated residual anomaly map, four prominent anomalies appear in sight. Notably, three of these anomalies are closely linked to the major volcanoes in the area: Colima (also recognized as Fuego), Nevado, and Cántaro. Moreover, the data indicate the existence of magnetic anomalies of different amplitudes and wavelengths apparently associated with intrusive bodies. The Colima and Nevado volcanoes are characterized by large amplitude dipolar anomalies. The inversion procedure reveals 3D causative bodies that can be recognized as shallower remnants of their magmatic reservoirs. They seem to be connected to larger and deeper bodies. The inversion procedure delineates four distinct source bodies. The deeper body among these primary structures displays a volumetric extent approximating 13.6 km³, positioned at depths spanning from 4.7 to 6.0 km below the summit. Another noticeable body, associated with the Colima volcano, has a semi-triangular shape with a volume of some 8.2 km3, located between 2.6 and 3.1 km. The third body, associated with Nevado, exhibits a vertically elongated shape located from depths of the order of 1.8–2.2 km. Towards the northeastern vicinity of Nevado, a fourth distinctive body becomes evident. This body also presents an elongated form, somewhat inclined in orientation, and occupies a depth interval of 2.2–2.6 km.