The VARION approach to volcanoes: case study on 2021 Etna eruptions

<p><span><span>The 2022 Tonga event</span> <span>highlight the necessity to have</span> <span>more and more</span> <span>kn</span><span>owledge about the</span> <span>activity</span><br><span>of</span> <span>volcanoes.</span> <span>To this point</span><span>, it is well known that volcanoes explosion can</span> <span>t</span><span>rigger ionospheric</span><br><span>perturbation detectable through the</span> <span>Global Navigation Satellite S</span><span>ystem (</span><span>GNSS</span><span>)</span> <span>signal</span> <span>[</span><span>1</span><span>]</span><span>.</span></span><span></span><span></span><span></span><span><br><span>T</span><span>he VARION (Variometric Approach for Real</span><span>-</span><span>Time Ionosphere Observation) algorithm has been</span><br><span>successfully applied to</span> <span>detection</span> <span>of ionospheric perturbations</span> <span>in several real</span><span>-</span><span>time scenarios [</span><span>2</span><span>, 3</span><span>].</span><br><span>VARION, thus, estimates sTEC (slant total electron</span> <span>content) variations starting from the single time</span><br><span>differences of geometry</span><span>-</span><span>free combinations of GNSS carrier</span><span>-</span><span>phase measurements.</span></span><span></span><span></span><span></span><span><br><span>The aim of this work</span> <span>is to an</span><span>a</span><span>lyse some</span> <span>Etna explosions</span> <span>occurr</span><span>ed in 202</span><span>1</span> <span>with the VARION algorithm</span><br><span>in order to</span> <span>better study the c</span><span>oupling between</span> <span>volcanoes and ionospher</span><span>e</span><span>. This study can pave the</span><br><span>way to</span> <span>a re</span><span>a</span><span>l</span><span>-</span><span>ti</span><span>me</span> <span>ionosp</span><span>heri</span><span>c</span> <span>monitoring o</span><span>f Etna volcano</span><span>.</span></span><span></span><span><br><span>[</span><span>1</span><span>]</span> <span>Manta, Fabio, et al. "Correlation between GNSS&#8208;TEC and eruption magnitude supports the use</span><br><span>of ionospheric sensing to complement volcanic hazard assessment." Journal of Geophysical</span><br><span>Research: Solid Earth 126.2 (2021): e2020JB020726.</span></span><span><br><span>[</span><span>2</span><span>]</span> <span>Ravanelli, Michela, et al. "GNSS total variometric approach: first demonstration of a tool for</span><br><span>real</span><span>-</span><span>time tsunami genesis estim</span><span>ation." Scientific Reports 11.1 (2021): 1</span><span>-</span><span>12.</span></span><span><br><span>[</span><span>3</span><span>]</span> <span>Sava</span><span>stano, Giorgio, et al. "Advantages of geostationary satellites for ionospheric anomaly</span><br><span>studies: Ionospheric plasma depletion following a rocket launch." Remote Sensing 11.14 (2019):</span><br><span>1734.</span></span></p>