Natural Hazards and Earth System Sciences (Mar 2011)

Atmospheric electrical field decrease during the <i>M = 4.1</i> Sousel earthquake (Portugal)

  • P. F. Biagi,
  • B. Caldeira,
  • J. F. Borges,
  • C. Serrano,
  • A. A. Araújo,
  • M. Tlemçani,
  • R. N. Rosa,
  • A. H. Reis,
  • M. Bezzeghoud,
  • H. G. Silva

DOI
https://doi.org/10.5194/nhess-11-987-2011
Journal volume & issue
Vol. 11, no. 3
pp. 987 – 991

Abstract

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In this paper, we report the observation of a significant decrease of the vertical component of the atmospheric electrical field in the Évora region (Portugal) during the M = 4.1 Sousel earthquake of 27 March 2010. The epicentre of the earthquake was 52 km from the observation site, which falls within the theoretical earthquake preparation radius. A simple interpretation based on hypothetical radon emissions is presented, and future experiments required to elucidate these observations are outlined. To our knowledge, this is the first reported observation of a decrease of the atmospheric electrical field preceding an earthquake.