The Internal Structure Of Paricutin And Tancítaro Volcanos, Mexico, From Rock Density Distributions

Abstract

Located in the Tarascan plateau, western Mexico, Paricutín volcano is the youngest monogenetic volcano in the country; it is located within 6 km of the only stratovolcano in that region: Tancítaro volcano. The objective is to define the location of Paricutín’s magma chamber and the magma conduits constituting its plumbing system. For that purpose, we use a high-resolution, satellite-derived gravity data set to obtain 3D density inversions at two spatial resolutions of 500 and 250 m. Results from the 500 m resolution led us to suspect that a branch of Tancítaro’s magma chamber fed Paricutín’s eruption; however, at this resolution, we could not find a magmatic path linking them. Results at the higher resolution (250 m) unveiled a channel within a high-density region, in which a vertical, low-density channel is located under Paricutín extending down to 5 km depth, including a region at sea level, that we associate with a small magma chamber owing to its shape and lower density. The volume identified as the magma chamber of Tancítaro volcano is enclosed by a formation of high-density material that appears to have been intruded prior to the emplacement of the Tancítaro magma chamber; its nature and composition cannot be determined with the available information.