Examples of Multi-Sensor Determination of Eruptive Source Parameters of Explosive Events at Mount Etna

Valentin Freret-Lorgeril,Simona Scollo,Costanza Bonadonna,Lorenzo Guerrieri,Frank Silvio Marzano,Maurizio Ripepe,Luigi Mereu,Franck Donnadieu,Giorgio Lacanna,Stefano Corradini,Dario Stelitano,Luca Merucci

doi:10.3390/rs13112097

Abstract

Multi-sensor strategies are key to the real-time determination of eruptive source parameters (ESPs) of explosive eruptions necessary to forecast accurately both tephra dispersal and deposition. To explore the capacity of these strategies in various eruptive conditions, we analyze data acquired by two Doppler radars, ground- and satellite-based infrared sensors, one infrasound array, visible video-monitoring cameras as well as data from tephra-fallout deposits associated with a weak and a strong paroxysmal event at Mount Etna (Italy). We find that the different sensors provide complementary observations that should be critically analyzed and combined to provide comprehensive estimates of ESPs. First, all measurements of plume height agree during the strong paroxysmal activity considered, whereas some discrepancies are found for the weak paroxysm due to rapid plume and cloud dilution. Second, the event duration, key to convert the total erupted mass (TEM) in the mass eruption rate (MER) and vice versa, varies depending on the sensor used, providing information on different phases of the paroxysm (i.e., unsteady lava fountaining, lava fountain-fed tephra plume, waning phase associated with plume and cloud expansion in the atmosphere). As a result, TEM and MER derived from different sensors also correspond to the different phases of the paroxysms. Finally, satellite retrievals for grain-size can be combined with radar data to provide a first approximation of total grain-size distribution (TGSD) in near real-time. Such a TGSD shows a promising agreement with the TGSD derived from the combination of satellite data and whole deposit grain-size distribution (WDGSD).

Highlights

The injection of large volumes of tephra into the atmosphere during explosive eruptions has the potential to cause air traffic disruption, while the associated fallout may impact public health, infrastructures, and various economic sectors [1,2]
Plume height can be independently determined at Etna based on at least three different remote sensing systems that are complementary in terms of detection limits and space-time resolution
Plume height can be independently determined at Etn based on at least three different remote sensing systems that are complementary in term of detection limits and space-time resolution

Summary

Introduction

The injection of large volumes of tephra into the atmosphere during explosive eruptions has the potential to cause air traffic disruption, while the associated fallout may impact public health, infrastructures, and various economic sectors (e.g., agriculture, tourism) [1,2]. The near real-time monitoring of active volcanoes is, critical and requires strategies that are valid for a large set of eruptive conditions. Due to intrinsic limitations (e.g., sensor detection limits, deposit exposure), individual strategies cannot provide a comprehensive characterization of all these ESPs. Recently, multi-sensor strategies have been developed to better constrain MER, HT, and TGSD from ground sampling, plume models, and available remote sensing systems [7,15,30,31,32,33,34]. Multi-sensor strategies are being used for the real-time determination of column height during volcano monitoring activities [22]

Methods

Results

Discussion

Conclusion