Volcanic soil gas He/CO ratio: a useful geochemical tool for real-time eruption forecasting.

At many dormant volcanoes, magmatic gases are not channeled through preferential degassing routes as fumaroles and only percolate through the flanks of the volcano in a diffuse way. This type of volcanic gas emission provides valuable information, even though the soil matrix contains an important atmospheric component. This study aimed to demonstrate that chemical ratios such as He/CO in soil gases provide excellent information on the evolution of volcanic unrest episodes and help forecast the volcanic eruption onset.

Diffuse CO degassing precursors of the January 2020 eruption of Taal volcano, Philippines.

On January 12, 2020, Taal volcano in Philippines erupted, 43 years after its previous eruption in 1977. This eruption was preceded by diffuse CO degassing precursory signals. Significant temporal variations in diffuse CO emission from Taal Main Crater Lake (TMLC) were observed across the ~ 12 years reaching high CO degassing rates in 2011 and 2017, with values typical of plume degassing volcanoes.

Dietary changes across time: Studying the indigenous period of La Gomera using δ C and δ N stable isotope analysis and radiocarbon dating.

Objectives: This article presents new radiocarbon and isotopic data to provide further information about the diet of the indigenous population of La Gomera and its possible changes across time.

Materials And Methods: δ C and δ N of 53 human and 19 faunal samples from different sites on the island have been obtained and analyzed. Of these, 52 have been radiocarbon dated to provide insight on chronological changes.