Distributed Acoustic Sensing (DAS) Earthquake Waveforms Recorded During the NEREIDS Experiment

Overview This dataset contains a comprehensive collection of earthquake waveforms recorded using Distributed Acoustic Sensing (DAS) on an existing fiber-optic cable during the NEREIDS experiment in Asteri (Peloponnese, Greece). The recording window spans from 7 October to 10 November 2025. The dataset captures 140 earthquakes detected by the National Observatory of Athens (NOA) within a 50 km radius of the cable's start point (Asteri dam), complete with supporting metadata, geolocated cable geometry, and core Python processing scripts. Please see the figure attached to this repository for the specific cable geometry and earthquake locations (cable_and_earthquake_distribution.png) Dataset Structure waveform_data/: 140 HDF5 files containing raw 20-second waveform records per event (beginning 5 seconds before estimated P-wave arrival**). Cable_geometry/: cable_coordinates_Asteri.csv (Geolocated channel coordinates). Catalogs/: list_of_events_from_NOA.csv (NOA event metadata and hypocentral locations). Codes/: das_class.py (core calibration and filtering class), plot_events_NEREIDS.py (example script), and requirements.txt. figures/: Sample reference plots (.pdf). **P-wave arrival is estimated at the cental channel of the cable assuming a P-wave velocity of 5.8 km/s and using earthquake hypocentral locations from NOA Technical Specifications Parameter Configuration Value Interrogator Unit Optasense QuantX Cable Length ~12.5 km Channel Count 6,300 channels Channel Spacing 2.04 m Gauge Length 10.3 m Sampling Frequency 500 Hz Laser Ping Rate 5000 Hz Data Conversion to Strain The raw HDF5 files store data as 16-bit digital counts. The code in das_class.py converts these counts to physical units via: $$\text{Raw Counts} \xrightarrow{\times \frac{2\pi}{2^{16}}} \text{Phase Shift (rad)} \xrightarrow{\text{Scaling}} \text{Strain } (\epsilon) \rightarrow \text{Microstrain } (\mu\epsilon)$$ Companion Resources Software Repository: A active development version of this processing pipeline, alongside a 2-event test suite (noa2025ugjsr.h5, noa2025umgvy.h5), is maintained on GitLab at: https://gitlab.ruhr-uni-bochum.de/bocchgxw/das-nereids/ Note: This Zenodo deposit represents the definitive, full-density archive containing all 140 earthquake records. Funding & Acknowledgments This research was made possible through the support of the European Union’s GEO-INQUIRE project (GA 101058518) and was partly funded by the VolkswagenStiftung (Volkswagen Foundation). The NEREIDS team would like to thank the National Observatory of Athens (Athens, Greece), the University of Patras (Patras, Greece), and the personnel at the Asteri dam for their invaluable support and assistance during the experiment License & Terms of Use Dataset Artifacts: Creative Commons Attribution 4.0 International (CC BY 4.0) Software/Scripts: MIT License Contact & Citation If you utilize these waveforms or code patterns in your research, please cite this Zenodo repository using the DOI provided on this page. Dr. Gian Maria Bocchini Institute of Geosciences, Ruhr University Bochum 📧 gian.bocchini(et)rub.de