This supplement contains GNSS displacement time series, fluid loading displacement time series predictions, and trajectory models for these time series. The time series are for the study regions of the paper: "Months-Long thousand-km-scale wobbling before great subduction earthquakes". These study regions are (1) Japan and surrounding countries and (2) Chile and surrounding countries. Network solution daily GNSS time series displacements in Chile and surrounding countries in the South American network have been produced by GFZ. Network solution daily GNSS time series of displacements in Japan have been produced by the Geospatial Information Authority of Japan (GSI). PPP daily GNSS time series of displacements in Japan and surrounding countries have been produced by the Nevada Geodetic Laboratory, Nevada Bureau of Mines and Geology, University of Nevada, Reno. Fluid loading predictions have been made using the HYDL, NTOL, NTAL, and SLEL products of the ESMGFZ. Readme ascii files in this data supplement contain instructions on how the data are ordered. Furthermore, the Readme file contains the relevant references and acknowledgments for readers who want to use these data in their own published studies.
Real-time fluid monitoring began in late 2020 in the East Eifel and currently includes 12 sites, such as abandoned CO₂ wells, mofettes, CO₂-rich springs, CO₂-rich soil, and a cold-water geyser in the West Eifel. For the first time, fluid data are being recorded continuously with a high temporal resolution of up to 1 Hz. Depending on the local site conditions, the following parameters are being monitored: instrument temperature and battery voltage; barometric pressure and temperature; meteorological parameters; water level, wellhead pressure, water temperature; radon in free gas phase; CO2 concentration and CO2 flux in soil gas. Data are transmitted hourly via FTP to GFZ. While we generally observe small seasonal variations, short-term transients related to heavy rain or local and distant earthquakes are indicated. Over longer periods, we observe trend changes in helium isotope ratios, radon concentration, and water temperature. For example, two sites exhibited significant helium isotope changes from 2021 to 2025, which appear to correlate with earthquake swarms at depth. These examples demonstrate the necessity of jointly interpreting meteorological, hydrogeological, geophysical, and geodetic data.