Processed airborne electromagnetic data Iliamna Volcano, Alaska June 2012

Airborne electromagnetic (AEM) and magnetic survey data were collected during June 2012 along 556 line-kilometers over Iliamna Volcano, Alaska. These data were collected in support of alteration and volcano flank instability mapping as part of the U.S. Geological Survey (USGS) Volcano Hazards Program. Data were acquired by SkyTEM Survey ApS SkyTEM304 system with the Soloy Helicopters Eurocopter Astar 350 B3 and Bell 407 dual-moment, time-domain helicopter-borne electromagnetic system together with a Geometrics G822A cesium vapor magnetometer with Kroum KMAG4 counter. The survey was flown at a nominal flight height of 30 meters (m) above terrain along block-style lines with a nominal spacing of 250 m. The survey was designed to cover the summit and flanks of Iliamna volcano and includes transit lines east of the volcano which provide additional information on nearby structures and glacial thickness and resistivity. There are data gaps near Iliamna’s summit due to poor flight visibility. Minimally processed binary AEM data received from the contractor were imported into the Aarhus Workbench software (Aarhus Geosoftware, Aarhus, Denmark) and processed. Filters were applied to inclinometer and spatial positioning data to smooth raw data and remove sensor drop outs. Altimeter data were filtered, smoothed, and manually edited to correct false altitudes associated with trees and other obstacles, resulting in processed altitude representative of the distance between the AEM sensor airframe and bare earth. Ground surface elevations were imported from Alaska's 5 m IFSAR Division of Geological and Geophysical Survey elevation dataset (DGGS, 2020, https://elevation.alaska.gov/). Electromagnetic data were averaged using a filter width of 4 seconds applied to both high moment and low moment data. Low-signal data were removed from the averaged data through a combination of filters and manual culling.

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  "010:12"
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  "geospatial"
]