Natural Hazards

, Volume 43, Issue 3, pp 333–350 | Cite as

Alert system to mitigate tephra fallout hazards at Mt. Etna Volcano, Italy

  • Salvatore Alparone
  • Daniele Andronico
  • Tiziana Sgroi
  • Ferruccio Ferrari
  • Luigi Lodato
  • Danilo Reitano
Original Paper


Volcanic eruptions may create a wide range of risks in inhabited areas and, as a consequence, major economic damage to the surrounding territory. An example of volcanic hazard was given between 1998 and 2001 by Mt. Etna volcano, in Italy, with its frequent paroxysmal explosive activity that caused more than a hundred fire-fountain episodes. In the period January–June 2000, in particular, 64 lava fountains took place at the Southeast Crater. During the most intense explosive phase of each episode, a sustained column often formed, reaching up to 6 km above the eruptive vent. Then, the column started to expand laterally causing more or less copious tephra fallout on the slopes of Etna; ash and lapilli, therefore, constituted a serious danger for vehicular and air traffic. A software and hardware warning system was developed to mitigate the volcanic hazard indicating the areas affected by potential ash and lapilli fallout. The alert system was mainly based on the good correspondence between the pattern of volcanic tremor amplitude and the evolution of explosive activity. When a fixed tremor threshold was exceeded, a semiautomatic process started to send faxes to Civil Defence and Municipalities directly affected by tephra fallout, together with information on wind directions from the Meteorological Office. The application of this methodology, during the last 14 eruptive episodes in 2000 and the 14 events occurred in 2001, demonstrated the good correspondence between the forecasts on the areas affected by tephra fallout and the effective tephra distribution on land. Despite the integrity of the performance provided by the alert system, small discrepancies occurred in the technical procedure of alerting, for which possible solutions have been discussed. The improvement of this type of system, could become basic for the Etnean region and be proposed for similar volcanic areas throughout the world.


Alert system Volcanic surveillance Volcanic tremor Lava fountain Tephra fallout 



We wish to thank Prof. Villari who proposed and discussed the problems of tephra fallout and correct alerting systems. Eugenio Privitera gave us precious support during the first months in which the alert system was tested. Alessandro Bonaccorso generously offered to help us by revising an early version of the manuscript. Special thanks are due to the Meteorological Office of Sigonella for providing information on wind conditions. We gratefully acknowledge Matthew Patrick and an anonymous reviewer for their constructive reviews of the manuscript and for greatly improving the English.


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Copyright information

© Springer Science+Business Media, Inc. 2007

Authors and Affiliations

  • Salvatore Alparone
    • 1
  • Daniele Andronico
    • 1
  • Tiziana Sgroi
    • 2
  • Ferruccio Ferrari
    • 1
  • Luigi Lodato
    • 1
  • Danilo Reitano
    • 1
  1. 1.Istituto Nazionale di Geofisica e Vulcanologia, Sezione di CataniaCataniaItaly
  2. 2.Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Roma 2CataniaItaly

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