Electric charging of eruptive clouds from Shiveluch Volcano caused by different types of explosions

The number of explosive eruptions at Shiveluch Volcano has significantly increased over the past years, which requires close volcanic monitoring using all available techniques. In order to implement a new monitoring technique into integrated methods of volcano monitoring, the authors analyze response to the intensity of the vertical component in the atmospheric electrical field (EZ AEF) during the movement of ash clouds. Two eruptions of different intensity that occurred December 16, 2016 and June 14, 2017 at Shiveluch were selected for study. We used a combination of satellite, seismic, and infrasound data to select signals in the EZ AEF field. Signals with negative polarity that accompanied ashfalls in the EZ AEF dynamics were registered for both eruptions within the closest area (< 50 km). In the former case, the ash cloud was “dry” and thus it caused aerial-electrical structure of the negatively charged cloud. In the latter case, a strong explosion sent into the atmosphere the large volume of ash and volcanic gases (98% in form of vapour) that resulted in the formation of a dipolar aerial-electrical structure caused by eolian differentiation within the closest area. At the distance of more than 100 km we registered a positive-going signal that is attributive to the aerial-electrical structure of the positively charged type of the cloud.

Electric charging of eruptive clouds from Shiveluch Volcano caused by different types of explosions

The number of explosive eruptions at Shiveluch Volcano has significantly increased over the past years, which requires close volcanic monitoring using all available techniques. In order to implement a new monitoring technique into integrated methods of volcano monitoring, the authors analyze response to the intensity of the vertical component in the atmospheric electrical field (EZ AEF) during the movement of ash clouds. Two eruptions of different intensity that occurred December 16, 2016 and June 14, 2017 at Shiveluch were selected for study. We used a combination of satellite, seismic, and infrasound data to select signals in the EZ AEF field. Signals with negative polarity that accompanied ashfalls in the EZ AEF dynamics were registered for both eruptions within the closest area (< 50 km). In the former case, the ash cloud was “dry” and thus it caused aerial-electrical structure of the negatively charged cloud. In the latter case, a strong explosion sent into the atmosphere the large volume of ash and volcanic gases (98% in form of vapour) that resulted in the formation of a dipolar aerial-electrical structure caused by eolian differentiation within the closest area. At the distance of more than 100 km we registered a positive-going signal that is attributive to the aerial-electrical structure of the positively charged type of the cloud.

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

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.