Internal Structure of the Southern and Central Colima Volcanic Complex, Western Mexico, Revealed by 3d Modeling of Aeromagnetic Data

We present the results of an aeromagnetic survey conducted on the central Colima Volcanic Complex in western Mexico. Four large anomalies emerge in the interpolated residual anomaly map; three of them are associated with the big volcanoes, Colima (also known as Fuego), Nevado de Colima, 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 sources. They seem to be connected to larger and deeper bodies. The inversion shows four distinct source bodies. The most deep main structure exhibit a volume of the order of 13.6 km3, found at depths between 4.7 and 6.0 km. Another important 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, has a vertically elongated shape located from depths of the order of 1.8 to 2.2 km. NE of the Nevado a fourth body is revealed, which is also characterized by elongated shape in a somewhat inclined position, located between 2.2 and 2.6 km.