Eruption dynamics leading to a volcanic thunderstorm—The January 2020 eruption of Taal volcano, Philippines

Abstract

Advances in global lightning detection have provided novel ways to characterize explosive volcanism. However, researchers are still at the early stages of understanding how volcanic plumes become electrified on different spatial and temporal scales. We deconstructed the phreatomagmatic eruption of Taal volcano (Philippines) on 12 January 2020 to investigate the origin of its powerful volcanic thunderstorm. Satellite analysis indicated that the water-rich plume rose >10 km high before creating lightning detected by Vaisala’s global lightning data set (GLD360). Flash rates increased with plume heights and cloud expansion over time, producing >70 flashes min-1. Photographs revealed a highly electrified region at the base of the umbrella cloud, where we infer strong convective updrafts and icy collisions enhanced the electrical activity. These findings inform a conceptual model with overlapping regimes of charge generation in wet eruptions—initially due to ash particle collisions near the vent, followed by thunderstorm-like electrification in icy regions of the upper plume. Despite the wide reach of Taal’s ash cloud, most of the lightning occurred within 20–30 km of the volcano, producing thousands of hazardous cloud-to-ground flashes over a densely populated area. The eruption demonstrates that volcanic lightning can pose a hazard in its own right, embedded within the broader hazards of explosive volcanism in an urban setting.

Responses of the AC/DC Global Electric Circuit to Volcanic Electrical Activity in the Hunga Tonga‐Hunga Ha'apai Eruption on 15 January 2022

“…In this study, 20 km was taken as the radius of the vent region. Note that this distance was also found empirically at other eruptions (Van Eaton et al., 2016, 2022) where lightning activity close to the vent was distinguished from that occurring further away from it.…”

“…Here the available water vapor concentration easily exceeds the saturation condition, and abundant condensate can form in both liquid and solid forms. Note that the vertical separation of these two lightning‐active regions, down close to the vent and higher in the troposphere, has been inferred in association with other water‐rich volcanic eruptions (Van Eaton et al., 2022). According to laboratory observations of triboelectrification (Méndez Harper et al., 2020), the expected high relative humidity throughout the ascending portion of this eruption cloud can lead to an order‐of‐magnitude reduction in the efficacy of this process.…”

“…Here the available water vapor concentration easily exceeds the saturation condition, and abundant condensate can form in both liquid and solid forms. Note that the vertical separation of these two lightning-active regions, down close to the vent and higher in the troposphere, has been inferred in association with other water-rich volcanic eruptions (Van Eaton et al, 2022).…”

“…(2020). Note that lightning tends to become detectable by LF/VLF networks only when the plume reaches the freezing level (Arason et al., 2011; Van Eaton et al., 2022; Woodhouse & Behnke, 2014).…”

A Terrestrial Gamma‐Ray Flash From the 2022 Hunga Tonga–Hunga Ha'apai Volcanic Eruption

“…As a submarine volcano, the plume of Hunga Tonga–Hunga Ha'apai likely had a large amount of entrained water (Yuen et al., 2022), so that water‐based mechanisms likely dominated the electrification process. High lightning rates are observed in volcanic plumes when the plumes reach altitudes that are cold enough for ice formation; also higher plumes correlate with stronger updrafts which increase electrification in regular thunderstorms (Behnke et al., 2012; Van Eaton et al., 2022). Based on the number of lightning flashes detected by GLD360 when Fermi GBM was within range, and assuming that the TGF production efficiency from the volcanic lightning is the same as thunderstorm lightning, we estimate that GBM should have detected ∼2 TGFs during the very high lightning rates of the 14–15 January 2022 eruption.…”