The European Physical Journal Special Topics

, Volume 224, Issue 4, pp 659–686

Soil radon (222Rn) monitoring at Furnas Volcano (São Miguel, Azores): Applications and challenges

Regular Article

DOI: 10.1140/epjst/e2015-02398-6

Cite this article as:
Silva, C., Ferreira, T., Viveiros, F. et al. Eur. Phys. J. Spec. Top. (2015) 224: 659. doi:10.1140/epjst/e2015-02398-6
Part of the following topical collections:
  1. Radon Applications in Geosciences - Progress & Perspectives

Abstract

A soil 222Rn continuous monitoring test was performed in three sampling points inside Furnas Volcano caldera and 222Rn concentration varied between 0 and 153000 Bq/m3. Multivariate regression and spectral analyses were applied to the time series registered in order to understand and filter the influence of external factors on soil 222Rn concentration and to recognise anomalies correlated with deep processes. The regression models show that barometric pressure, soil water content, soil temperature, soil CO2 flux, air temperature, relative air humidity and wind speed are the statistical meaningful variables explaining between 15.8% and 73.6% of 222Rn variations. Spectral analysis allowed to identify seasonal variations and daily variations associated with one cycle per day on winter months only in one of the monitored sites. This diurnal variation is correlated with air temperature, relative air humidity and wind speed cycles. The change in the location of the sampling points was caused by both artificial and natural constrains. On the three monitoring sites, after a period of continuous register, a sudden drop on the 222Rn concentration values was observed and the cause is still under debate. The work performed can be applied for seismovolcanic monitoring and for public health risk assessment.

Copyright information

© EDP Sciences and Springer 2015

Authors and Affiliations

  • C. Silva
    • 1
    • 2
  • T. Ferreira
    • 2
  • F. Viveiros
    • 2
  • P. Allard
    • 3
  1. 1.Centro de Vulcanologia e Avaliação de Riscos Geológicos, Universidade dos AçoresPonta DelgadaPortugal
  2. 2.Centro de Informação e Vigilância Sismovulcânica dos Açores, Universidade dos AçoresPonta DelgadaPortugal
  3. 3.Institut de Physique du Globe de ParisIPGP, ParisFrance