127-7 An Analysis of Volcanic Lightning and its Controlling Factors

Session: Mineralogy, Geochemistry, Petrology, and Volcanology Student Session

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Volcanic lightning, first documented during the 79 AD eruption of Mount Vesuvius, occurs when volcanic plumes become electrically charged through particle interactions. Three distinct types exist: (1) vent lightning- small, rapid discharges at the vent created when silicates fracture; (2) near-vent lightning- moderately-sized discharges generated through tephra collisions within turbulent plumes; and (3) plume lightning- large discharges created by ice charging above the -20°C isotherm. This study investigates and quantifies relationships between volcanic lightning occurrence and controlling factors across six recent eruptions (Redoubt 2009, Eyjafjallajökull 2010, Kelud 2014, Calbuco 2015, Fuego 2018, Sakurajima 2019). Data on volcanic parameters (plume height, mass eruption rate, ash characteristics) and atmospheric conditions (humidity, wind speed) were compiled from multiple peer-reviewed studies and online databases. Lightning data were collected from both very low frequency (VLF) and very high frequency (VHF) systems and standardized using VLF:VHF ratios. Linear regression analysis reveals that plume dynamics demonstrate the strongest correlations (r² ≥ 0.79) among all factors studied. Ash grain size distribution showed moderate correlation (r² = 0.50), while composition exhibited weaker relationships (r² ≤ 0.35), indicating that physical ash characteristics control electrification more than the composition. Atmospheric conditions showed weak correlations (r² ≤ 0.19), contradicting some previous findings. Our results highlight the complex nature of volcanic lightning generation and establish plume dynamics as primary controlling factors. Understanding these relationships advances volcanic lightning prediction capabilities and contributes to real-time eruption monitoring when direct observation of an eruption is impossible.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-7892

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