Emisión difusa de hidrógeno en el Volcán Poás, Costa Rica

Abstract

We report the results of the study of dif fuse H2 emission from Poas volcano, Costa Rica. Three surveys were carried out in 2000, 2001 and 2002, to investigate soil H 2 distribution in and around Poas summit crater and to evaluate diffuse H 2 emission as a potential geochemical tool for the Poas volcano monitoring pro- gram. Soil H2 contents showed a wide range of concentrations from 0.4 to 7,059 ppmV. Most of the study area showed low levels of H2 in the soil atmosphere, and the highest values of soil gas H 2 were just observed inside the summit crater of Poas volcano for the 2001 and 2002 surveys. These surface geochemical changes coinci- de with an increase of the fumarolic activity as well as soil temperature rose inside the crater during this study. The results here reported suggest changes in the Poas volcanic-hydrothermal system, therefore monitoring dif- fuse H2 emission could be useful for the volcanic surveillance of Poas volcano.