Unrest at Domuyo Volcano, Argentina, Detected by Geophysical and Geodetic Data and Morphometric Analysis

Abstract

New volcanic unrest has been detected in the Domuyo Volcanic Center (DVC), to the east of the Andes Southern Volcanic Zone in Argentina. To better understand this activity, we investigated new seismic monitoring data, gravimetric and magnetic campaign data, and interferometric synthetic aperture radar (InSAR) deformation maps, and we derived an image of the magma plumbing system and the likely source of the unrest episode. Seismic events recorded during 2017–2018 nucleate beneath the southwestern flank of the DVC. Ground deformation maps derived from InSAR processing of Sentinel-1 data exhibit an inflation area exceeding 300 km2, from 2014 to at least March 2018, which can be explained by an inflating sill model located 7 km deep. The Bouguer anomaly reveals a negative density contrast of ~35 km wavelength, which is spatially coincident with the InSAR pattern. Our 3D density modeling suggests a body approximately 4–6 km deep with a density contrast of –550 kg/m3. Therefore, the geophysical and geodetic data allow identification of the plumbing system that is subject to inflation at these shallow crustal depths. We compared the presence and dimensions of the inferred doming area to the drainage patterns of the area, which support long-established incremental uplift according to morphometric analysis. Future studies will allow us to investigate further whether the new unrest is hydrothermal or magmatic in origin.

Unrest at the Laguna del Maule volcanic field 2005–2020: renewed acceleration of deformation

“…It has been uplifting faster than 200 mm/year since 2007 (Feigl et al 2014;Le Mével et al 2015;Le Mével et al 2016). Episodes of unrest characterized by ground uplift are commonly observed at large silicic caldera systems (Sandri et al 2017), as illustrated by the recent unrest at Domuyo volcano in Argentina (Astort et al 2019;Lundgren et al 2020), Long Valley caldera (Montgomery-Brown et al 2015), and Yellowstone caldera (Chang et al 2010). Episodes of uplift without subsequent eruptions have also been observed at mafic calderas such as Alcedo volcano in the Galapagos (Galetto et al 2019).…”

The dynamics of large silicic systems from satellite remote sensing observations: the intriguing case of Domuyo volcano, Argentina

“…A new analysis of gravity, magnetic, and InSAR data from Sentinel-1 only (during the current inflation phase) describes the state of the system 30 . Gravity data suggests that the geodetically inferred 7 km deep source could be fed by a volatile-rich magma 30 .…”

“…A new analysis of gravity, magnetic, and InSAR data from Sentinel-1 only (during the current inflation phase) describes the state of the system 30 . Gravity data suggests that the geodetically inferred 7 km deep source could be fed by a volatile-rich magma 30 . This interpretation is consistent with our second and third models with surface warming driven by an influx of new magma into the shallow (6–7 km depth) reservoir and subsequent gas percolation to the surface and interaction with hydrothermal systems.…”

“…This includes, for example, the formation of plutons 55 and the remobilization of melt within mush and plutons as part of transcrustal magma reservoirs 56,57 . In the case of Domuyo, there is still a great lack of knowledge regarding its geologic history and its present state, although inclusion of gravity observations suggests an influx of melt into the shallow crustal reservoir 30 . The long repose time (~ 100 ka) is not exceptional for large silicic magmatic systems 58 , composed of complex volumes of melt and mush 59,60 .…”

“…They considered the high (~ 86%) mantle He contribution surprising for a system with no eruptive activity in 100 ka. A new analysis of gravity, magnetic, InSAR surface deformation, and geomorphology data at Domuyo found that recent (2015–2018) inflation is consistent with volatile rich magma intruded at 7 km depth 30 .

Figure 1 Domuyo volcanic complex.

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