DOI: 10.5880/gfz.2.1.2021.002
title: Shiveluch volcano 2012-2019 photogrammetric dataset

description: Here we present a photogrammetric dataset on the 2018-2019 eruption episode at Shiveluch Volcano, one of the most active volcanoes in Kamchatka Peninsula. The data were acquired by optical sensors and complemented by thermal sensors. The optical satellite images were tri-stereo panchromatic 1-m resolution imagery acquired on 18 July 2018 with Pléiades satellite PHR1B sensor. We processed the data in Erdas Imagine 2015 v15.1. For the relative orientation of the images, 37 tie points were calculated automatically with further manual correction, and for the interior and exterior orientation, Rational Polynomial Coefficients block adjustment, which is a transformation between pixels to latitude, longitude, and height information, was automatically employed. After the image orientation, we obtained a photogrammetric model with a total root mean square error (RMSE) of 0.2 m. By using the Enhanced Automatic Terrain Extraction module (eATE) with normalized cross correlation algorithm as implemented in the Erdas Imagine software, we were able to extract a 2 m resolution point cloud (PC) referenced to the WGS84 coordinate system UTM57 zone. This PC was filtered with the CloudCompare v2.9.1 noise filter and then manually cleaned with the CloudCompare segmentation tool. As strong volcanic steam emissions caused a large gap in the PC at the NE part of the dome, we used a 5 m resolution DEM constructed from TanDEM-X data to fill the gap and obtain the missing topography. TanDEM-X is a bistatic SAR mission, formed by adding a second, almost identical spacecraft, to TerraSAR-X. Therefore, it allows the acquisition of two simultaneous SAR imageries over the same area, eliminating possible temporal decorrelations between them and maintaining a normal baseline between 250 and 500 m, which is suitable for SAR interferometry for DEM generation. We used the interferometric module in ENVI SARscape to build the interferogram, perform the unwrapping step and finally convert it into height information using forward transformation from radar to geographic coordinates. The RMSE of the generated DEM is evaluated based on the coherence value, i.e. quality of the interferogram, and is estimated to be approximately 5 m.
description: The helicopter surveys allowed us to acquire nadir and oblique aerial images collected during overflights on 12 July 2012 with Canon EOS 20D conventional digital camera (focal length - 14.183 mm, resolution - 3,504×2,336 px), and on 22 August 2019 and 22 October 2019 with PhaseOne IXA 160 digital aerial camera (focal length - 28 mm, resolution - 8,984×6,732 px). The average flying height was 4,000 m a.s.l. for the nadir survey and 3,200 m a.s.l. for the oblique survey. We performed the photogrammetric processing of the images in Agisoft Metashape 1.5.2. For interior orientation, we set the cameras’ parameters (focal length and sensor size). Relative orientation was performed automatically by the image alignment and tie points calculation. For the exterior orientation and ground control points (GCPs) assignment, we used coordinates taken from stable topographic prominences identified in the 1979 photogrammetric model, which is referenced to the USSR State Geodetic Network coordinate system. The total RMSEs of the aerial models’ orientation varies from 1.5 m to 2 m. As a result of processing, we obtained three aerial PCs with a 2 m average resolution, which were then filtered and cleaned in the same way described above. The gaps caused by the volcanic steam emissions and by the atmospheric clouds were closed by manual points collection using the anaglyph stereo mode of Photomod 5, which was performed by placing a floating mark on the visible surface and stores XYZ coordinates of each point. The aerial PCs had the same spatial scale as the Pleiades PC but were shifted in geo-position due to the different coordinate systems. To compare the PCs, we aligned the aerial PCs to the Pleiades PC with several points on the rim of the amphitheater using the CloudCompare alignment tool. The RMSEs of the alignment vary from 2.3 to 3.1 m. Thus, we obtained four stacked PCs in WGS84 UTM57 and were able to calculate differences between them. We outlined areas of the lava dome including the talus, separately for each date and calculated volumes between two consecutive PCs within these specific areas. We also acquired thermal infrared images of the lava dome by recording from a helicopter together with the optical survey before and after the 29 August 2019 eruption. On the first flight, we used a FLIR Tau 2 camera with a 9 mm lens and a TEAX ThermalCapture frame grabber set to a sampling rate of 8 Hz. The resulting images had a resolution of 640×512 px and provided radiometric temperature data. The images were processed and exported using Thermoviewer (v3.0.4), assuming a constant emissivity of 0.95, a transmissivity of 0.7 as well as environmental and path temperatures of 10 C°. For the second flight, we used a ThermaCAM P640 camera at a resolution of 640×480 px, exported and processed with FLIR Tools (v.5.13), assuming the same environmental parameters as before. Our set of photogrammetric data let us to explore the 2018-2019 eruptive events at Shiveluch in the frame of complex construction-destruction behavior, as well as the the influence of tectonic structural control on it's current activity.