DOI: 10.5061/dryad.s1rn8pkn8
title: Data from: Volcanic ash affected by lightning during the Hunga 2022 eruption

description: This study estimates the amount of airborne volcanic ash that may be
 structurally or electromagnetically affected by volcanic lightning during
 the January 15, 2022, eruption of Hunga volcano (Kingdom of Tonga).
 Methods to calculate lightning channel sizes and volumes are provided, in
 addition to methods for calculating mass amounts of ash affected by both
 the high temperatures and the magnetic fields generated by
 lightning.  This study reveals that even though physical evidence
 of volcanic lightning may be limited, ash particles will still be affected
 by the electromagnetic fields produced by the lightning discharge. The
 extent of these effects will be a function of lightning properties, ash
 properties, and location of the ash in relation to the discharge channel.
 There are three datasets provided, and all are available for public use.
description: # Data from: Volcanic ash affected by lightning during the Hunga 2022
 eruption Dataset DOI:
 [10.5061/dryad.s1rn8pkn8](https://doi.org/10.5061/dryad.s1rn8pkn8) ##
 Description of the data and file structure `Dataset_S1-2026.xlsx`: Subset
 of lightning data reported by Van Eaton et al. (2023). We used lightning
 flashes recorded on only January 15, 2022 for the calculations in this
 study, and thus, the data reported are only for that specific day, not the
 entire eruption. The original publication should be referred to for
 additional information when using these data. There are four worksheets:
 1. "Ground based flashes Jan15" contains all flashes detected by
 the sensors for largest explosion on January 15, 2022; 2.
 "Ground-based rates" contains the lightning flash rates at
 specific distances from the vent for explosions January 13-15, 2022; 3.
 "Optical GLM flashes and rates" contains the volcanic lightning
 detected by the Geostationary Lightning Mapper on January 15, 2022, flash
 area (used to quantify flash length in our study) and the associated flash
 rates; 4. "Volcanic plume dimensions" were calculated during the
 course of the 2022 events by Van Eaton et al., 2023, and we use their
 results for January 15, 2022 to determine an average plume volume during
 that phase of the eruption.  For the following datasets, both an Excel
 Spreadsheet and csv file are provided. `Dataset_S2-2026.xlsx` and
 `Dataset_S2-2026.csv`: Parameters used in [Magnetic Field Calculation
 provided by the National Centers for Environmental
 Information.](https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#igrfwmm) These results were obtained using Magnetic Model: DGRF2020 (calculator version 1.2.1). Users can visit the website and input the volcano, date, and altitude of interest to get magnetic field total intensity and also values for the x, y, and z components.  The latitude and longitude of the volcano were provided by the calculator database once the name of the volcano is entered. Two different altitudes above mean sea level (10 km and 55 km) were checked but did not result in substantially different values (42.3 and 41.4 mT, respectively). `Dataset_S3-2026.xlsx` and `Dataset_S3-2026.csv`: All calculations for the values reported in the text and in Tables 2 and 3.  ### Files and variables #### File: Dataset_S1-2026.xlsx **Description:** Subset of lightning data reported by Van Eaton et al. (2023).We used lightning flashes recorded on only January 15, 2022 for the calculations in this study. Empty cells exist but do not represent missing data. #### File: Dataset_S2-2026.xls and Dataset_S2-2026.csv **Description:** Parameters used in Magnetic Field Calculation provided by the National Centers for Environmental Information. The latitude and longitude of the volcano were provided by the calculator database and two different altitudes above mean sea level (10 km and 55 km) were checked but did not result in substantially different values (42.3 and 41.4 mT), respectively. Empty cells exist but do not represent missing data. #### File: Dataset_S3-2026.xls and Dataset_S3-2026.csv **Description:** All calculations for the values reported in the text and in Tables 2 and 3. Empty cells exist but do not represent missing data. Equations for the associated values can be found in the manuscript text and are listed below. Variables determined by the individual flash are in **bold.** channel radius = 0.097*(**peak current**^(1/3))*SQRT(**time**); where peak current is in Amps and time is in seconds channel volume = PI()*(**channel radius**^2)***channel length;** values in meters The ideal melting zone is roughly 10% of the channel volume. Mass of ash within the channel is a product of the channel volume and ash concentration. B field (T) at channel radius (m) =(permittivity of free space***peak current**)/(2PI()***channel radius**) permittivity of free space = (4PI())(10^-7) ## Code/software n/a