Pléiades co- and post-eruption survey in Cumbre Vieja volcano, La Palma, Spain

Introduction: 

This repository consists of a series of topographic surfaces of the Cumbre Vieja volcano (La Palma, Spain), presented as a series of Digital Elevation Models (DEMs) obtained from multiple Pléiades stereoscopic surveys acquired from the 22^nd of September 2021 until the 14^th of January 2022. We also present a series of grids showing the difference of elevation between the pre-eruption surface and the co- and post-eruption surface, which reveal the lava thickness of the eruption. This was used to calculate the lava volume and effusion rate or Time Average Discharge Rate (TADR) at the time of the Pléiades surveys.

Data: 

1 – Pléiades stereo images: 

A pre-eruption Pléiades stereopair was collected from 2013. A total of ten stereopairs were collected between the 23^th of September 2021 and 2^nd of October 2021 as part of the CIEST² initiative (https://www.poleterresolide.fr/ciest-2-nouvelle-generation-2/). Four additional pairs were acquired between the 11^th of December 2021 and the 14^th of January 2022 as part of the Dinamis initiative (https://dinamis.data-terra.org/). However, only some of these stereopairs were acquired with sufficiently large cloud-free areas around the eruption site. The following Pléiades stereo images were processed and are presented in this repository: 

Table 1: Date, sensor and image ID of the Pléiades stereoimages used in this repository. 

2 – Lidar pre-eruption surface: 

A lidar survey acquired in 2016 by the Spanish Mapping Agency (IGN, Spain) was downloaded through the portal: http://centrodedescargas.cnig.es/CentroDescargas/catalogo.do?Serie=LIDAR#. Specifically, we used the Digital Surface Model (DSM) product, available in 2x2 m Ground Sampling Distance (GSD). This means that trees and human structures were removed based using classification of the multiple returns of the lidar pulses. The coordinate reference system is REGCAN (UTM zone 28N, EPSG: 32628), and the heights are orthometric, using the height reference system REDNAP, built upon the geoid EGM08. Using the REDNAP geoid model, we converted the heights to meters above ellipsoid (WGS84), since the Pléiades data is acquired with satellite attitudes referred to the ellipsoid WGS84. 

Methods:

The Pléiades stereoimages were processed using the Ames StereoPipeline (ASP, Shean et al., 2016, see ASP branch in repository), yielding a DEM in 2x2m GSD and an orthoimage in 0.5x0.5m GSD. The processing was done using as only input the stereoimages and their orientation information, as Rational Polynomial Coefficients (RPCs). The parallel_stereo routine performs all the steps needed in the correlation of the stereoimages, yielding a pointcloud which is then interpolated using the routine point2dem. Besides default parameters, the parallel_stereo parameters used for creation of the DEMs were the standard parameters, plus the following ones: 

--corr-tile-size 2048 --sgm-collar-size 256 --corr-seed-mode 3 --corr-max-levels 2 --corr-timeout 900 --cost-mode 3 --subpixel-mode 9 --corr-kernel 7 7 --subpixel-kernel 15 15

Once the DEM was created, DEM co-registration was applying in order to align and minimize positional biases between the pre-eruption DEM and the Pléiades DEMs. We followed the co-registration method of Nuth & Kääb (2011), implemented by David Shean’s co-registration routines (https://github.com/dshean/demcoreg, Shean et al., 2016). The co-registration involved a horizontal and vertical shift of the Pléiades DEMs, as well as a planar tilt correction. The horizontal offset obtained from the DEM co-registration was also applied to the Pléiades orthoimages.

Lava outlines were manually digitized from the co-registered Pléiades orthoimages, excluding kipukas and major building constructions which were not covered by the lavas. The lava outlines are available as GeoPackages in the “GPKG” branch of the repository.

Lava volume calculations were done using the average lava thickness, multiplied by the area covered by the lavas. The uncertainty in volume was assumed to be the Normalized Mean Absolute Deviation (NMAD, Höhle and Höhle, 2009), multiplied by the lava area. The TADR was calculated as the total volume divided by the time, in seconds, between the start of the eruption, defined as 2021-09-19 11:58:00 local time, and the acquisition of the Pléiades images. For the total TADR, we used the volume extracted from the Pléiades images from the 1^st of January 2022, divided by the observed time of beginning and end of the eruption, defined as 2021-12-13 22:21:00, local time. The TADR values shown in this repository do not account for submarine lavas nor tephra deposits.

In addition, another set of DEMs were produced automatically as soon as the images were made available by the on-demand processing service DSM-OPT provided by ForM@Ter (https://en.poleterresolide.fr/on-demand-processing/#/mns). This processing is based on Micmac (D. Michéa and J.-P. Malet / EOST; E. Pointal, IPGP, Rupnik, 2017). The DEMs produced correspond to the file created automatically “A2_dsm_denoised.tif”. They were obtained in 1x1 m GSD, and they were cropped over the area of interest. These DEMs have not been co-registered. These data are available in the “MM” branch in the repository. 

Results: Lava area, volumes and effusion rate: 

Table 2: results of lava area, thickness, lava volume and TADR since the start of the eruption. 

Repository structure:

zenodo_lapalma/
├── ASP
│   ├── 20130630_1202_lapalma_PL_2x2m_UTM28N_ASP_DEM.tif
│   ├── 20210926_1158_lapalma_PL_2x2m_UTM28N_ASP_DEM.tif
│   ├── 20210926_1158_lapalma_PL_2x2m_UTM28N_thickness.tif
│   ├── 20211002_1202_lapalma_PL_2x2m_UTM28N_ASP_DEM.tif
│   ├── 20211002_1202_lapalma_PL_2x2m_UTM28N_thickness.tif
│   ├── 20220101_1202_lapalma_PL_2x2m_UTM28N_ASP_DEM.tif
│   ├── 20220101_1202_lapalma_PL_2x2m_UTM28N_thickness.tif
│   ├── 20220114_1202_lapalma_PL_2x2m_UTM28N_ASP_DEM.tif
│   └── 20220114_1202_lapalma_PL_2x2m_UTM28N_thickness.tif
├── GPKG
│   ├── 20210925_1202_lapalma_PL_UTM28N_outline.gpkg
│   ├── 20211002_1202_lapalma_PL_UTM28N_outline.gpkg
│   └── 20220101_1202_lapalma_PL_UTM28N_outline.gpkg
└── MM
    ├── 20130630_1202_PL_1x1m_UTM28N_MM_DEM.tif
    ├── 20210926_1158_PL_1x1m_UTM28N_MM_DEM.tif
    ├── 20211002_1230_PL_1x1m_UTM28N_MM_DEM.tif
    ├── 20220101_1202_PL_1x1m_UTM28N_MM_DEM.tif
    └── 20220114_1202_PL_1x1m_UTM28N_MM_DEM.tif

Acknowledgements: 

Pléiades images were provided under the CIEST² initiative (CIEST2 is part of ForM@Ter (https://en.poleterresolide.fr/ ) and supported by ISDeform National Service of Observation) for the reference image acquired in 2013 and from the 23^rd of September to the 2^nd of October 2021, and through the Dinamis program (CNES, France) from the 12^th of December 2021 to the 14^th of January 2022 (image Pléiades©CNES2013,©CNES2021,©CNES2022, distribution AIRBUS DS) 

Dataset Attribution 

This dataset is licensed under a Creative Commons CC BY-NC 4.0 International License (Attribution-NonCommercial).
Attribution required for copies and derivative works:

The underlying dataset from which this work has been derived includes Pleiades material ©CNES (2013,2021,2022), distributed by AIRBUS DS, and data provided by the Spanish Mapping Agency (IGN, Spain), all rights reserved.

Dataset Citation 

Belart and Pinel (2022). “Pléiades co- and post-eruption survey in Cumbre Vieja volcano, La Palma, Spain”. Dataset distributed on Zenodo: 10.5281/zenodo.5833771

References: 

Höhle, J. and Höhle, M.: Accuracy assessment of digital elevation models by means of robust statistical methods, ISPRS J. Photogramm. Remote Sens., 64, 398–406, https://doi.org/10.1016/j.isprsjprs.2009.02.003, 2009.

Nuth, C. and Kääb, A.: Co-registration and bias corrections of satellite elevation datasets for quantifying glacier thickness change, The Cryosphere, 5, 271–290, https://doi.org/10.5194/tc-5-271-2011, 2011.

Rupnik, E., Daakir, M., & Deseilligny, M. P.: MicMac – a free, open-source solution for photogrammetry. Open Geospatial Data, Software and Standards, 2(1), 1-9, 2017.

Shean, D. E., Alexandrov, O., Moratto, Z. M., Smith, B. E., Joughin, I. R., Porter, C., and Morin, P.: An automated, open-source pipeline for mass production of digital elevation models (DEMs) from very-high-resolution commercial stereo satellite imagery, ISPRS J. Photogramm. Remote Sens., 116, 101–117, https://doi.org/10.1016/j.isprsjprs.2016.03.012, 2016.