The intriguing dynamics of Domuyo volcano, Argentina, as inferred from satellite remote sensing observations

Abstract:

Domuyo volcano is an interesting case of a long dormant volcano with ongoing unrest extending back more than a decade to the limits of interferometric synthetic aperture radar (InSAR) and thermal time series. Its most recent magmatic eruptive activity dates back roughly 100,000 years, yet it contains the second largest hydrothermal system in the world after Yellowstone caldera. Since 2014, Domuyo has been undergoing quasi-steady inflation at a rate of roughly 12-15 cm/year in the radar line-of-sight (LOS). Analysis through 2019 (Lundgren et al., 2020; https://doi.org/10.1038/s41598-020-67982-8) found that the InSAR time series, dating back to 2008, showed deflation from 2008 through 2011, null deformation 2013-2014, followed by ongoing inflation since mid-2014. Deformation was accompanied by a lagged thermal time series representing the whole-edifice thermal output. The lag and sign of correlation of the geodetic versus thermal time series could be interpreted in terms of top-down or bottom-up models, with implications for long-term thermal and gas diffusion versus deeper-sourced magma injection. Through 2019, the volume increase for Domuyo’s shallow tabular magma reservoir at ~6.5 km depth was ~0.037 km³/year since 2014, a rate slightly exceeding that of nearby Laguna del Maule caldera, though over a shorter time interval.

Here we present new InSAR time series analyses from Sentinel-1 and ALOS-2 that extend the geodetic time series through 2020. Preliminary results from the 2019-2020 austral summer show that the inflation of Domuyo appears to be slowing, with new analysis of the temporally dense Sentinel-1 data displaying a sigmoidal inflation time series that is curiously similar to that found at Laguna del Maule (Le Mével et al., 2016; doi:10.1002/2016JB013066). The non-linearity of the current inflation and thermal time series allows us to investigate time variable physical models. The geodetic data can be modeled as a coupled thermal-fluid-mechanical system following the approach of Le Mével et al. (2016), including a realistic geotherm and temperature-dependent viscosity. Future models will explore the coupled gas diffusion-solid mechanics processes to explain the relative lags between the geodetic and thermal time series in order to understand the present and future behavior of the system.