Tectonic ans seismicity in the Parícutin - Tancítaro Volcanic Region

Abstract

Active tectonomagmatic regions are characterized for the presence of regional fault systems, as well as recurrent volcanism and seismicity. The Parícutin-Tancítaro Volcanic Region is located in the Michoacán-Guanajuato Volcanic Field on the central part of the Transmexican Volcanic Belt and represents a structurally complex zone with high volcanic density. This work presents a morphotectonic and seismicity analysis in the Parícutin-Tancítaro Volcanic Region. Here, we observe the coexistence of two regional fault systems: 1) the Cotija-Nueva Italia Fault System, which groups NW-SE oriented faults and fractures, and represent the limit between the Meseta P'urhépecha area to the north and the Peribán - Los Reyes Graben and the Bajo Balsas Basin to the south. 2) The Tepalcatepec-Tangancícuaro Fault System, which groups NE-SW oriented faults, including frequent volcanic lineaments with the same direction; this system influences the formation of the Peribán - Los Reyes Graben.

The Parícutin-Tancítaro Region presents an intense seismic activity and its characterized by the record of at least 7 seismic swarms during the last 80 years. Independently the precision on the location and relatively occurrence depth of the seismic swarms, those overlap with the regional faults systems (previously mentioned) and with late Pleistocene, Holocene and recent volcanic lineaments (e.g. Parícutin volcano (1943-1952), Pedregal volcano (470-710), Astillero volcano (620-680), and Metate volcano (1000-1600)). The concurrence and recurrence of the three tectonomagmatic elements suggest strongly that the tectonic structures ease the ascension and emplacement of magmas, probably associated to shallow reservoirs to at depths of 4-5 km, 9-10 km and 14-16 km. This scenario carries inherent geological hazards related to volcanic and seismic activity, which could affect the communities settled in the region. Therefore, its necessary monitoring tectonomagmatic processes evolution in the Parícutin-Tancítaro Volcanic Region through geophysical techniques and permanent analysis of data.