The dataset is an extended and updated version of the homogenized regional earthquake catalogue of the Marmara region, north-western Turkey, presented in Wollin et al. (2018) and Becker et al. (2023). It is built on the regional Turkish seismicity catalogues provided by AFAD (Disaster and Emergency Management Presidency of Turkey) and KOERI (Kandilli Observatory and Earthquake Research Institute) and spans the time interval 2021-2023. All events available in these two catalogues in the wider Marmara region were combined and duplicate events removed. A total of 2242 events having at least 6 P- and/or S-picks were located using the NLLoc software (Lomax et al., 2000, 2009) in Octtree mode utilizing automatic picks obtained with the PhaseNet algorithm (Zhu & Beroza, 2019) for all available waveforms. The magnitude range is between M0.5 and M5.1 and covers mainly the area 40.00S-41.25S and 27.00E-30.00E which was used as search region for the regional catalogs. The full description of the data and methods is provided in the data description file.
The dataset contains three seismicity catalogs covering the first 5 days of the aftershock sequence of the Mw 7.8 Karamanmaraş and Mw 7.6 Elbistan earthquakes that occurred in Türkiye on February 6th, 2023. The catalogs are derived from machine learning (ML) approaches operating on continuous data from 38 permanent seismological stations covering the area of the aftershock sequence and span the time interval 06.02.2023-10.02.2023. The seismological stations are operated by AFAD (Disaster and Emergency Management Presidency of Turkey) and KOERI (Kandilli Observatory and Earthquake Research Institute). Automatic P- and S-phase picks were obtained using the deep learning PhaseNet software (Zhu & Beroza, 2019), and either GaMMA (Zhu et al., 2022) or GENIE (McBrearty & Beroza, 2023) routines were used to associate these phases into seismic events. The probabilitic NLLoc earthquake location software (Lomax et al., 2009) was used to produce single event locations and final relative relocations were obtained after applying the hypoDD software (Waldhauser & Ellsworth, 2000). This resulted in two single event location NLLoc aftershock catalogs based on GaMMA and GENIE event association and containing 17,550 and 14,805 event detections in the time interval 06.02.2023 01:18 UTC - 11.02.2023 00:00 UTC, respectively.
The hypoDD based catalog of better constrained relative relocations contains 5,215 events. The magnitude range is between M-0.1 and M6.9 with time-variable magnitude of completeness. The catalog covers the area 36.00S-39.00S and 35.40E-40.00E. The full description of the data and methods is provided in the data description file.
The dataset is an extended and updated version of the homogenized regional earthquake catalogue of the Marmara region, north-western Turkey, presented in Bohnhof et al. (2017) and Wollin et al. (2018). It is built on the regional Turkish seismicity catalogues provided by AFAD (Disaster and Emergency Management Presidency of Turkey) and KOERI (Kandilli Observatory and Earthquake Research Institute) and spans the time interval 2006-2020. All events available in these two catalogues in the wider Marmara region were combined and dublicate events removed. A total of 13812 events having at least 6 P- and/or S-picks were located using the NLLoc software (Lomax et al., 2000, 2009) in Octtree mode utilizing automatic picks (see Wollin et al., 2018 for details) for all available waveforms. The magnitude range is between M0.3 and M5.7 with time-variable magnitude of completeness and covers the area 39.70S-41.50S and 26.0E-30.65E. The full description of the data and methods is provided in the data description file.
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.