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Peer reviewed: True, Acknowledgements: We would like to thank two reviewers whose comments have greatly improved the manuscript. TW would like to thank Jonas Gliß, Benjamin Esse and Mathew Varnam for their development of, and subsequent support with, their valuable Python packages. We also acknowledge the support of Silvana Hidalgo and colleagues at IGEPN for their work on the installation of an instrument on El Reventador, Ecuador. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government., Since its introduction to volcanology in the mid-2000 s, the SO2 camera has become an important instrument for the acquisition of accurate and high time-resolution SO2 emission rates, aiding in hazard assessment and volcanological research. However, with the exception of a few locations (Stromboli, Etna, Kīlauea), hitherto the majority of measurements have been made on discrete field campaigns, which provide only brief snapshots into a volcano’s activity. Here, we present the development of a new, low-cost, low-power SO2 camera for permanent deployment on volcanoes, facilitating long-term, quasi-continuous (daylight hours only) measurements. We then discuss preliminary datasets from Lascar and Kīlauea volcanoes, where instruments are now in continuous operation. Further proliferation of such instrumentation has the potential to greatly improve our understanding of the transient nature of volcanic activity, as well as aiding volcano monitoring/eruption forecasting.

Details of ongoing changes in geomorphology and structure of nested volcanic craters are lacking due to the difficult and hazardous access. In this study, we present a novel unoccupied aircraft system (UAS) dataset collected at Lascar, northern Chile, one of the most active volcanoes in the Central Volcanic Zone of the Andes. Lascar features nested craters, the deepest crater of which has experienced repeated lava dome emplacement and numerous violent explosions in recent decades. We performed UAS surveys in 2017 and 2020 to collect the optical and thermal imaging data of the active crater. By applying the Structure-from-Motion (SfM) method, we obtained centimeter-scale optical and thermal orthomosaics as well as digital terrain models. We quantify the spatial and volumetric changes that occurred during the observation period. The results show material removal from the crater wall and a significant accumulation of volcanic material on the crater floor. The thermal orthomosaic helps identify thermal anomalies and the spatial distribution of fumaroles. The highest thermal anomaly was found on the crater floor and delimited by ring structures. Both the optical orthomosaics and DEMs from 2017 and 2020 showed a consistent ring structure, which remained stable following two explosive events. Possible localized subsidence was observed within the ring structure. Consequently, we hypothesize that the ring structure represents the surface expression of underlying concentric fracture systems and constrains a narrow conduit top. Our results provide important insights into an active crater’s morphological, structural, and thermal features, with implications for understanding the formation mechanism and evolution of volcanic craters.

Subduction zones represent the interface between Earth’s interior (crust and mantle) and exterior (atmosphere and oceans), where carbon and other volatile elements are actively cycled between Earth reservoirs by plate tectonics. Helium is a sensitive tracer of volatile sources and can be used to deconvolute mantle and crustal sources in arcs; however it is not thought to be recycled into the mantle by subduction processes. In contrast, carbon is readily recycled, mostly in the form of carbon-rich sediments, and can thus be used to understand volatile delivery via subduction. Further, carbon is chemically-reactive and isotope fractionation can be used to determine the main processes controlling volatile movements within arc systems. Here, we report helium isotope and abundance data for 42 deeply-sourced fluid and gas samples from the Central Volcanic Zone (CVZ) and Southern Volcanic Zone (SVZ) of the Andean Convergent Margin (ACM). Data are used to assess the influence of subduction parameters (e.g., crustal thickness, subduction inputs, and convergence rate) on the composition of volatiles in surface volcanic fluid and gas emissions. He isotopes from the CVZ backarc range from 0.1 to 2.6 RA (n = 23), with the highest values in the Puna and the lowest in the Sub-Andean foreland fold-and-thrust belt. Atmosphere-corrected He isotopes from the SVZ range from 0.7 to 5.0 RA (n = 19). Taken together, these data reveal a clear southeastward increase in 3He/4He, with the highest values (in the SVZ) falling below the nominal range associated with pure upper mantle helium (8 ± 1 RA), approaching the mean He isotope value for arc gases of (5.4 ± 1.9 RA). Notably, the lowest values are found in the CVZ, suggesting more significant crustal inputs (i.e., assimilation of 4He) to the helium budget. The crustal thickness in the CVZ (up to 70 km) is significantly larger than in the SVZ, where it is just ∼40 km. We suggest that crustal thickness exerts a primary control on the extent of fluid-crust interaction, as helium and other volatiles rise through the upper plate in the ACM. We also report carbon isotopes from (n = 11) sites in the CVZ, where δ13C varies between −15.3‰ and −1.2‰ [vs. Vienna Pee Dee Belemnite (VPDB)] and CO2/3He values that vary by over two orders of magnitude (6.9 × 108–1.7 × 1011). In the SVZ, carbon isotope ratios are also reported from (n = 13) sites and vary between −17.2‰ and −4.1‰. CO2/3He values vary by over four orders of magnitude (4.7 × 107–1.7 × 1012). Low δ13C and CO2/3He values are consistent with CO2 removal (e.g., calcite precipitation and gas dissolution) in shallow hydrothermal systems. Carbon isotope fractionation modeling suggests that calcite precipitation occurs at temperatures coincident with the upper temperature limit for life (122°C), suggesting that biology may play a role in C-He systematics of arc-related volcanic fluid and gas emissions.

This work presents chemical and isotopic (delta13C-CO2, delta13C-CH4, 3He, 4He, 20Ne, 40Ar, 36Ar, delta18O and deltaD) data on fluid discharges from the Colpitas-Taapaca volcanic-hydrothermal system, located close to the Taapaca Volcanic Complex, with the aim to investigate the physical-chemical conditions of the fluid source and to provide a preliminary evaluation of the geothermic potential of the study area. Colpitas thermal springs (to 56 °C) and part of the cold springs (

RESUMEN: En este trabajo se examina el término “kawésqar”, el cual presenta algunos problemas no solo en el ámbito de la lexicografía o de la lingüística, sino también en otros como la legislación chilena o en las relaciones entre las comunidades miembros del grupo étnico que llevan este nombre. Asimismo, se abordan otros nombres que ha recibido la etnia y que han sido diversamente interpretados a través del tiempo.