Cyclic activity of the Fuego de Colima volcano (Mexico): insights from satellite thermal data and nonlinear models

Abstract

The Fuego de Colima volcano (Mexico) shows a complex eruptive behavior, with periods of rapid and slow lava dome growth punctuated by explosive activity. We reconstructed the weekly discharge rate average between 1998 and 2018 by means of satellite thermal data integrated with published discharge rate data. By using spectral and wavelet analysis, we found a multiyear long-term, multi- month intermediate-term, and multi-week short-term cyclic behavior during the period of the investigated eruptive ac- tivity like that of many other dome-forming volcanoes. We use numerical modeling in order to investigate the nonlinear cyclic eruptive behavior considering a magma feeding sys- tem composed of a dual or a single magma chamber con- nected to the surface through an elastic dyke developing into a cylinder conduit in the shallowest part. We investigated cases in which the periodicity is controlled by (i) the cou- pled deep–shallow magma reservoirs, (ii) the single shallow chamber, and (iii) the elastic shallow dyke when it is fed by a fixed influx rate or constant pressure. Due to the limitations of the current modeling approach, there is no single config- uration that can reproduce all the periodicities on the three different timescales. The model outputs indicate that the ob- served multiyear periodicity (1.5–2.5 years) can be described by the fluctuations controlled by a shallow magma chamber with a volume of 20–50 km3 coupled with a deep reservoir of ca. 500 km3, connected through a deep elastic dyke. The multi-month periodicity (ca. 5–10 months) appears to be con- trolled by the shallow magma chamber for the same range of volumes. The short-term multi-week periodicity (ca. 2.5– 5 weeks) can be reproduced considering a fixed influx rate or constant pressure at the base of the shallower dyke. This work provides new insights on the nonlinear cyclic behavior of Fuego de Colima and a general framework for comprehen- sion of the eruptive behavior of andesitic volcanoes.