Geology topics

Susana Layana

Publications and source records attributed to Susana Layana.

3 recordsLinked to original sources

USGS2025

Origins and fluxes of gas emissions from the Central Volcanic Zone of the Andes

We present geochemical data from gas samples from ∼1200 km of arc in the Central Volcanic Zone of the Andes (CVZA), the volcanic arc with the thickest (∼70 km) continental crust globally. The primary goals of this study are to characterize and understand how magmatic gases interact with hydrothermal systems, assess the origins of the major gas species, and constrain gas emission rates. To this end, we use gas chemistry, isotope compositions of H, O, He, C, and S, and SO 2 fluxes from the CVZA. Gas and isotope ratios (CO 2 /S T , CO 2 /CH 4 , H 2 O/S T , δ 13 C, δ 34 S, 3 He/ 4 He) vary dramatically as magmatic gases are progressively affected by hydrothermal processes, reflecting removal and crustal sequestration of reactive species (e.g., S) and addition of less reactive meteoric and crustal components (e.g., He). The observed variations are similar in magnitude to those expected during the magmatic reactivation of volcanoes with hydrothermal systems. Carbon and sulfur isotope compositions of the highest temperature emissions (97–408 °C) are typical of arc magmatic gases. Helium isotope compositions reach values similar to upper mantle in some volcanic gases indicating that transcustal magma systems are effective conduits for volatiles, even through very thick continental crust. However, He isotopes are highly sensitive to even low degrees of hydrothermal interaction and radiogenic overprinting. Previous work has significantly underestimated volatile fluxes from the CVZA; however, emission rates from this study also appear to be lower than typical arcs, which may be related to crustal thickness.

Central Volcanic Zone of the Andes↗

USGS2024

Preface to the focus section on volcano monitoring in the Americas

From the Andes to the Aleutian Islands, the Americas are rich with volcanism that spans a diverse range of tectonic settings, eruptive styles, levels of activity, and hazards. Over the past 120 yr, the Americas have witnessed catastrophic volcanic eruptions that have significantly impacted nearby populations. Notable events include the 8 May 1902, pyroclastic density current from Mount Pelée in Martinique, which resulted in the loss of over 28,000 lives in Saint‐Pierre, with only one or two survivors (Lacroix, 1904), and the 1985 eruption of Nevado del Ruiz in Colombia, which triggered a lahar and left an estimated...

Seismological Research Letters↗

USGS2023

A new permanent, low-cost, low-power SO2 camera for continuous measurement of volcanic emissions

Since its introduction to volcanology in the mid-2000 s, the SO 2 camera has become an important instrument for the acquisition of accurate and high time-resolution SO 2 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 SO 2 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.

Frontiers in Earth Science↗