The 2010 eruption of Eyjafjallajökull: Lightning and plume charge structure

Abstract

Six Lightning Mapping Array (LMA) stations were deployed in April 2010 around Eyjafjallajökull volcano in southern Iceland. Single-station LMA observations were made during the first explosive period (14-18 April), and three-dimensional LMA observations were made during the second explosive period (5-22 May). The single-station observations revealed that continuous RF electrical activity caused by high rates of small vent discharges occurred during the first explosive period, but not the second, indicating that the strength of vent charging varied between the first and second explosive periods. During the second explosive period, very little lightning was detected between 5 and 10 May, while moderate rates of lightning were detected between 11 and 21 May, signaling that another change occurred on 11 May that affected plume electrification. The data do not make clear if it was changing eruptive activity or changing meteorological activity that resulted in the sudden onset of lightning. The plume charge structure during the second explosive period was inferred from the three-dimensional lightning data, showing that the dominant charge structure varied between a positive monopole and a negative-over-positive dipole. The predominance of a low-altitude region of positive charge and the observation that electrical activity was concentrated near the vent indicate that net positive vent charging was dominating the electrification.

Compositional and Mineralogical Effects on Ice Nucleation Activity of Volcanic Ash

“…These results suggest that ash enriched in K 2 O will promote nucleation at higher temperatures compared to ash enriched in MnO and TiO 2 . These findings support previous observations which indicate that larger explosions are more likely to produce lightning than smaller explosions [5] and that the height of the eruption column will correlate with the number of lightning discharges [7,10], as larger explosions create more ash particles of smaller sizes and are sometimes sourced from magmas with evolved compositions. There are many other characteristics of volcanic plumes that may contribute to lightning generation that cannot be constrained by the study presented here, as the relationship between INA and volcanic ash composition represents only one aspect of the processes involved.…”

“…Remote sensing studies of volcanic lightning have determined the altitude of the −20 • C isotherm Heterogeneous ice nucleation will occur on volcanic ash particles between the −10 °C and −20 °C isotherm [8,9], the latter of which is the highest temperature examined in this study using both deposition-mode and immersion-mode experiments. Based upon remote sensing studies of volcanic lightning, the −20 °C isotherm occurs at an altitude ranging from 4 to 10 km [10][11][12][13]. Scale to the left side of the figure does not reflect the true height of the eruption column.…”

Characterization and applications of VLF/LF source locations from lightning using the Huntsville Alabama Marx Meter Array

“…The difference in the speed is mostly due to the fact that the first VHF source occurs ∼ 580 μs prior to the first VLF/LF source. These speeds are somewhat larger than other published values of 1 − 2 × 10 5 m/s [e.g., Shao et al , ; Behnke et al , ]. After ∼ 4 ms, sources detected by both HAMMA and NALMA begin to propagate horizontally.…”

Volcanic lightning and plume behavior reveal evolving hazards during the April 2015 eruption of Calbuco volcano, Chile

“…Recently, volcanic lightning has been recognized as a valuable complementary tool [ Behnke and McNutt , ]. With continued expansion and improvement of global networks such as the World Wide Lightning Location Network (WWLLN) [ Lay et al ., ], and deployable lightning mapping arrays [ Behnke et al ., , ], it is increasingly apparent that volcanic lightning could become a crucial part of eruption detection and monitoring operations in the future. With these developments come new questions about the role of lightning in eruption processes.…”