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COST-G GravIS RL02 Ice-Mass Change Products

GRACE/GRACE-FO Level-3 product based on COST-G RL02 Level-2B products (Dahle & Murböck, 2025) representing ice-mass changes for the Antarctic Ice Sheet (AIS) and the Greenland Ice Sheet (GIS). The ice-mass changes are provided both as basin average product and as gridded product. Basin-average ice-mass changes are obtained using the inversion procedure based on a forward modelling approach as described in Sasgen et al. (2013) for the AIS and Sasgen et al. (2012) for the GIS. Gridded ice-mass changes are provided at polar-stereographic grids with a grid spacing of 50 x 50 km^2. The applied algorithm is based on tailored sensitivity kernels (Döhne et al., 2023; Groh & Horwath, 2021), and has also been used to generate gravimetric mass balance products within the ESA Climate Change Initiative (CCI) projects for the AIS and the GIS. These Level-3 products are visualized at GFZ's web portal GravIS (https://gravis.gfz.de). --------------------------------------------------------------------------------------------- Version History: 13 March 2026: Initial release of the data (Version 0001).

Earthquake catalogues from a hydrothermal system near Istanbul derived with template matching and AI techniques

The three datasets presented here are high-resolution catalogs containing origin time of seismic events for the same region and time range that have derived using AI-based techniques and a matched filter search. The corresponding standard catalogs from the agencies AFAD and KOERI are available under https://tdvms.afad.gov.tr/ (last accessed 28/07/2022) and http://www.koeri.boun.edu.tr/sismo/2/earthquake-catalog/ (last accessed 28/07/2022), respectively, when searching in the bulletin for longitude 28.80-29.10, latitude 40.4-40.625, and from November 1st 2018 to January 31th, 2019. Specifications for the three catalogs are. (i) Catalog derived utilizing AI-based techniques. We applied the PhaseNet deep learning method (Zhu & Beroza, 2019) to detect and pick the P-and S- waves of seismic events embedded in continuous seismic recordings from 16 stations surrounding the region of interest resampled at 100 Hz. The method was trained on a dataset from Northern California, but has been shown to generalize well to other tectonic settings. The picks were associated into seismic events using the GaMMA association method (Zhu et al., 2022). Manual check of the waveforms from all detections led to 516 seismic events with clear waveforms retained for further processing. (ii) Template matching catalog A. We applied the matched filter algorithm EQcorrscan (Chamberlain et al., 2017) to the two nearby seismic stations with the largest data recovery during the period of interest, ARMT and MDNY. We utilized 14 manually picked template events with M > 2 that occurred in the region of interest during the analyzed time period, which were recorded in both stations. As a first criteria to remove false detections, we retained only detections exhibiting a Median Absolute Deviation (MAD) larger than eight. We required detections from different templates to be at least 1.5 seconds apart. To remove duplicate detections (e.g., detections of the same event by different templates), we retained the detections with the highest average correlation if multiple detections occurred within 2.5 seconds. As a second criteria, we calculated cross-correlation derived phase-picks. A pick was declared if the maximum normalized correlation between the signal of the template event and of the detection exceeds 0.7. We correlated the signals in a short window of ±0.3 seconds around the assumed pick time based on a time-shifted version of the template phase-pick. We retained the S-pick exhibiting the higher cross-correlation value with respect to the template. Following this step, we considered only detections with ≥ 2 picks. In case of events with only two picks we ensured that that were from the same station to have control on the ts-tp and therefore the distance of the event from the detecting station. This catalog contains 2,462 seismic events (all manually reviewed) with magnitudes MW in the range [-2.4, 4.5]. Since we were not able to locate the events from this catalog, we considered as “origin time” the time of the first arrival. (iii) Template matching catalog B. We derived a second template matching catalog utilizing twelve of the closest seismic stations displaying high seismic data recovery during the analyzed time period. An initial list of detections was generated following the same steps as for the Template Matching Catalog A, with the additional requirement that all detections must contain at least one picks from one of the two closest stations, ARMT and MDNY. All detections from this catalog were also manually reviewed. The full description of the data processing and creation of the catalog is provided in the article “Stress changes can trigger earthquake sequences in a hydrothermal region south of Istanbul” by Martínez-Garzón et al., currently under review in Geophysical Research Letters.

COST-G GravIS RL01 Ice-Mass Change Products

GRACE/GRACE-FO Level-3 products based on COST-G RL01 Level-2B products (Dahle & Murböck, 2020) representing ice-mass changes for the Antarctic Ice Sheet (AIS) and the Greenland Ice Sheet (GIS). The ice-mass changes are provided both as basin average product and as gridded product. Basin-average ice-mass changes are obtained using the inversion procedure based on a forward modelling approach as described in Sasgen et al. (2013) for the AIS and Sasgen et al. (2012) for the GIS. Gridded ice-mass changes are provided at polar-stereographic grids with a grid spacing of 50 x 50 km^2. The applied algorithm is based on tailored sensitivity kernels (Groh & Horwath, 2016), and has also been used to generate gravimetric mass balance products within the ESA Climate Change Initiative (CCI) projects for the AIS and the GIS. These Level-3 products are visualized at GFZ's web portal GravIS (https://gravis.gfz.de). --------------------------------------------------------------------------------------------- Version History: 21 April 2023: Release of Version 0003. This is an update of Version 0002 of the same data set (see changelog). 15 June 2020: Initial release of the data. Note that the initial version number is 0002 in order to reflect the consistent data processing of this data set and Version 0002 of the data set Sasgen et al. (2019, https://doi.org/10.5880/GFZ.GRAVIS_06_L3_ICE). All changes and updates are documented in the changelog available via the data download section. Previously released versions of this data set are available in the "old-version" subfolder in the data download folder.

GFZ GravIS RL06 Ice-Mass Change Products

GRACE/GRACE-FO Level-3 products based on GFZ RL06 Level-2B products (Dahle & Murböck, 2019) representing ice-mass changes for the Antarctic Ice Sheet (AIS) and the Greenland Ice Sheet (GIS). The ice-mass changes are provided both as basin average product and as gridded product. Basin-average ice-mass changes are obtained using the inversion procedure based on a forward modelling approach as described in Sasgen et al. (2013) for the AIS and Sasgen et al. (2012) for the GIS. Gridded ice-mass changes are provided at polar-stereographic grids with a grid spacing of 50 x 50 km^2. The applied algorithm is based on tailored sensitivity kernels (Döhne et al., 2023; Groh & Horwath, 2021), and has also been used to generate gravimetric mass balance products within the ESA Climate Change Initiative (CCI) projects for the AIS and the GIS. These Level-3 products are visualized at GFZ's web portal GravIS (https://gravis.gfz.de). --------------------------------------------------------------------------------------------- Version History: 13 March 2026: Release of Version 0005. This is an update of Version 0004 of the same data set (see changelog). 16 January 2025: Release of Version 0004. This is an update of Version 0003 of the same data set (see changelog). 21 April 2023: Release of Version 0003. This is an update of Version 0002 of the same data set (see changelog). 09 June 2020: Release of Version 0002. This is an update of Version 0001 of the same data set (see changelog). All changes and updates are documented in the changelog available via the data download section. Previously released versions of this data set are available in the "old_versions" subfolder of the data download folder.

SELF II: Sea Level Fluctuations in the Mediterranean: Interactions with Climate Processes and Vertical Crustal Movements

SELF II uses the determination of absolute sea level and of its variations to study the present interactions as well as of those of the recent past among the ocean, the atmosphere and the Earth's crust and to develop appropriate models to assess future aspects. The main topics are: - to improve the long-term monitoring of sea-level variability by applying the most advanced geodetic techniques, including satellite altimetry and airborne laser - to study past sea levels in the Mediterranean in order to better understand the current processes - to study the effects of the atmosphere/ocean interaction and crustal movements on coastal sea levels in order to provide a bases for hazard assessment. Particular objectives of the project are: - a first assessment of rates of vertical movements of the tide gauge benchmarks - optimize the GPS and gravity observation strategies for a cost-effective determination of height changes, in particular by deploying water vapor radiometers - a detailed assessment of the quality and usefulness of the available tide gauge and sea level data - compute the temporal (seasonal and interannual) and the spatial variations of the sea-surface topography of the Mediterranean and Black Sea from ERS-1, ERS-2, TOPEX satellite altimetry and airborne laser profiling.

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