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Deformation-induced topographic effect due to shallow dyke: Etna December 2018 fissure eruption case study

In: Contributions to Geophysics and Geodesy, vol. 51, no. 2
Peter Vajda Číslo ORCID - Pavol Zahorec Číslo ORCID - Juraj Papčo Číslo ORCID - Richard Czikhardt Číslo ORCID
Detaily:
Rok, strany: 2021, 165 - 188
Jazyk: eng
Kľúčové slová:
volcano geodesy, 4D microgravimetry, spatiotemporal gravity change, DITE, surface deformation
O článku:
Gravitational effect of surface deformation is in 4D microgravimetry treated as the deformation-induced topographic effect (DITE). The DITE field is computed using Newtonian volumetric integration which requires high resolution digital elevation model (DEM) and vertical displacement field in areal form. If only elevation changes on benchmarks of the gravimetric network are available, instead of the vertical displacement field, the DITE on benchmarks can be evaluated only approximately, using a planar Bouguer or a normal free-air-effect (nFAE) approximation. Here we analyse the adequacy and accuracy of these two approximations in a case study for the December 2018 fissure eruption on Etna accompanied by significant surface deformation caused primarily by a relatively shallow dyke. The outcome is that in volcanic areas of similar morphology as that over the Etna summit area, and for surface deformation fields due to relatively shallow dykes, neither the Bouguer nor the nFAE approximation of the DITE is accurate enough. In such situations the residual gravity changes should be computed with both the Bouguer and nFAE corrections and interpreted as two marginal cases. In addition we analyse also a correction for the effect of benchmark elevation change based on the topographically modelled (predicted) vertical gradient of gravity (VGG) meant to approximate the in-situ VGG values at benchmarks. This correction does not appear suitable to approximate the DITE in conditions of our case study or in broader sense.
Ako citovať:
ISO 690:
Vajda, P., Zahorec, P., Papčo, J., Czikhardt, R. 2021. Deformation-induced topographic effect due to shallow dyke: Etna December 2018 fissure eruption case study. In Contributions to Geophysics and Geodesy, vol. 51, no.2, pp. 165-188. DOI: https://doi.org/10.31577/congeo.2021.51.2.4

APA:
Vajda, P., Zahorec, P., Papčo, J., Czikhardt, R. (2021). Deformation-induced topographic effect due to shallow dyke: Etna December 2018 fissure eruption case study. Contributions to Geophysics and Geodesy, 51(2), 165-188. DOI: https://doi.org/10.31577/congeo.2021.51.2.4
O vydaní:
Vydavateľ: ESI SAS
Publikované: 29. 6. 2021
Verejná licencia:
CC BY-NC-ND