The first pan-Alpine surface-gravity database, a modern compilation that crosses frontiers

authored by

Pavol Zahorec, Juraj Papčo, Roman Pašteka, Miroslav Bielik, Sylvain Bonvalot, Carla Braitenberg, Jörg Ebbing, Gerald Gabriel, Andrej Gosar, Adam Grand, Hans Jürgen Götze, György Hetényi, Nils Holzrichter, Edi Kissling, Urs Marti, Bruno Meurers, Jan Mrlina, Ema Nogová, Alberto Pastorutti, Corinne Salaun, Matteo Scarponi, Josef Sebera, Lucia Seoane, Peter Skiba, Eszter Szucs, Matej Varga

Abstract

The AlpArray Gravity Research Group (AAGRG), as part of the European AlpArray program, focuses on the compilation of a homogeneous surface-based gravity data set across the Alpine area. In 2017 10 European countries in the Alpine realm agreed to contribute with gravity data for a new compilation of the Alpine gravity field in an area spanning from 2 to 23 E and from 41 to 51 N. This compilation relies on existing national gravity databases and, for the Ligurian and the Adriatic seas, on shipborne data of the Service Hydrographique et Oc anographique de la Marine and of the Bureau Gravim trique International. Furthermore, for the Ivrea zone in the Western Alps, recently acquired data were added to the database. This first pan-Alpine gravity data map is homogeneous regarding input data sets, applied methods and all corrections, as well as reference frames. Here, the AAGRG presents the data set of the recalculated gravity fields on a 4 km_4 km grid for public release and a 2 km_2 km grid for special request. The final products also include calculated values for mass and bathymetry corrections of the measured gravity at each grid point, as well as height. This allows users to use later customized densities for their own calculations of mass corrections. Correction densities used are 2670 kgm-3 for landmasses, 1030 kgm-3 for water masses above the ellipsoid and 1640 kgm-3 for those below the ellipsoid and 1000 kgm-3 for lake water masses. The correction radius was set to the Hayford zone O2 (167 km). The new Bouguer anomaly is station completed (CBA) and compiled according to the most modern criteria and reference frames (both positioning and gravity), including atmospheric corrections. Special emphasis was put on the gravity effect of the numerous lakes in the study area, which can have an effect of up to 5 mGal for gravity stations located at shorelines with steep slopes, e.g., for the rather deep reservoirs in the Alps. The results of an error statistic based on cross validations and/or interpolation residuals are provided for the entire database. As an example, the interpolation residuals of the Austrian data set range between about 8 and C8 mGal and the cross-validation residuals between -14 and C10 mGal; standard deviations are well below 1 mGal. The accuracy of the newly compiled gravity database is close to-5 mGal for most areas. A first interpretation of the new map shows that the resolution of the gravity anomalies is suited for applications ranging from intra-crustal- to crustal-scale modeling to interdisciplinary studies on the regional and continental scales, as well as applications as joint inversion with other data sets. The data are published with the DOI doi.org/10.5880/fidgeo.2020.045 (Zahorec et al., 2021) via GFZ Data Services.

Organisation(s)

Institute of Geology

External Organisation(s)

Slovak Academy of Sciences
Slovak University of Technology in Bratislava
Comenius University
Bureau Gravimétrique International (BGI)
Centre national d’études spatiales (CNES)
University of Trieste
Kiel University
Leibniz Institute for Applied Geophysics (LIAG)
Seismology and Geology Office, Ljubljana
University of Ljubljana
University of Lausanne (UNIL)
ETH Zurich
Federal Office of Topography (Swisstopo)
University of Vienna
Czech Academy of Sciences (CAS)
Service hydrographique et océanographique de la Marine (Shom)
Institute of Earth Physics and Space Science (ELKH)

Type

Article

Journal

Earth system science data

Volume

Pages

2165-2209

No. of pages

ISSN

1866-3508

Publication date

19.05.2021

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Earth and Planetary Sciences

Sustainable Development Goals

SDG 14 - Life Below Water

Electronic version(s)

https://doi.org/10.5194/essd-13-2165-2021 (Access: Open)