Articles | Volume 17, issue 9
Nat. Hazards Earth Syst. Sci., 17, 1461–1468, 2017
https://doi.org/10.5194/nhess-17-1461-2017
Nat. Hazards Earth Syst. Sci., 17, 1461–1468, 2017
https://doi.org/10.5194/nhess-17-1461-2017

Research article 06 Sep 2017

Research article | 06 Sep 2017

On a reported effect in ionospheric TEC around the time of the 6 April 2009 L'Aquila earthquake

Fabrizio Masci1, Jeremy N. Thomas2,3,4, and James A. Secan2 Fabrizio Masci et al.
  • 1Istituto Nazionale di Geofisica e Vulcanologia, L'Aquila, Italy
  • 2NorthWest Research Associates, Redmond, Washington, USA
  • 3Department of Electrical and Computer Engineering, DigiPen Institute of Technology, Redmond, Washington, USA
  • 4Department of Earth and Space Sciences, University of Washington, Seattle, Washington, USA

Abstract. In a report published in Advances in Space Research, Nenovski et al. (2015) analyse ionospheric TEC (total electron content) data from GPS measurements around the time of the 6 April 2009 Mw 6. 1 L'Aquila (Italy) earthquake. According to the authors, TEC difference (DTEC) calculated from two GPS (Global Positioning System) receivers in central Italy shows a hump-like shape (an increase followed by a decrease) during the hours just before and shortly after the main shock. They maintain that the hump-like shape is anomalous and may be related to the earthquake. We show that the DTEC increase in the hours before the shock, as well as its subsequent slow decrease, does not have any characteristic that might support a possible relationship with the earthquake. We have also conducted our own independent analysis using the same GPS data analysed by Nenovski et al. (2015). We have found a diurnal variation in DTEC time series that shows hump-like shapes like that reported by Nenovski et al. (2015) throughout the investigated period. This demonstrates that the hump-like shape in DTEC close to the time of the 6 April earthquake is not anomalous and cannot be considered a possible earthquake-related effect.

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In a recent paper, the authors report the analysis of ionospheric TEC data from GPS measurements around the time of the 6 April 2009 L'Aquila earthquake. According to them, an anomalous change in TEC difference from two GPS receivers in central Italy may be explained as related to the earthquake. We have conducted our own independent analysis using the same GPS data. We have shown that in TEC difference there is no evidence of actual seismogenic effects close to the time of L'Aquila earthquake.
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