# Integrated Earthquake Catalog III: Gakkel Ridge, Knipovich Ridge, and Svalbard Archipelago
## 2 Materials and Methods  
The region considered in the present paper (Figure 2) covers zones that were not included in the Eastern (catalog I) and Western (catalog II) sectors of the Russian Arctic. The territory is directly adjacent to the Eastern and Western sectors, but does not intersect with them. The schematic coverage map for catalogs I, II, and III is presented in (Figure S1, see Supplementary). Figure 2: Map of the studied region with earthquake epicenters from the ISC catalog: events with \(mb^{\text{ISC}}\) and \(mb^{\text{NEIC}}\) magnitude determinations are marked in blue, and events with \(Mw^{\text{GCMT}}\) determinations are marked in red. MFZ and SFZ are Molloy and Spitsbergen fracture zones. Dashed lines delineate sub-regions Svalbard (**A**), Knipovich (**B**), and Gakkel (**C**). The set of initial data was compiled from five earthquake catalogs (Table 1):  
1. The Arctic catalog from the annual journals Earthquakes in the USSR 1962-1991, Earthquakes in Northern Eurasia 1992-2017, and Earthquakes in Russia 2018-2021 (hereinafter ARC);
2. The catalog of the FCIAR network (Arkhangelsk network) 2008-2017 from the annual journals of Earthquakes in Northern Eurasia (hereinafter ARKH);
3. The catalog of the Svalbard Archipelago territory for 2010-2021 from the annual journals of Earthquakes in Russia (hereinafter SHB);
4. The ISC 1962-2022 catalog, which is a composite and contains data from many world and also Russian agencies (Table S1, see Supplementary);
5. The catalog Seismicity of the western sector of the Russian Arctic for 1962-2020 [29] (hereinafter Morozov). The Morozov catalog was recently presented in [29]. In this catalog, earthquakes are relocated based on the analysis and merging of all available seismic bulletins from Russian and European seismic networks using modern velocity models. The Morozov catalog covers the shelf zone of the Western Sector of the Russian Arctic, which we included in our previous study [28], but some earthquakes were relocated [29] from the shelf to the Gakkel Ridge. We include these events in our catalog, since we consider determinations [29] to be the most reliable. According to [30; 31], a large number of small seismic events registered in the Svalbard archipelago are ice-quakes. Such events are not presented in Russian catalogs. The ISC catalog includes 16 non-earthquake events (explosions and glacial events), all of them in Svalbard. One of these events is presented in the ARC catalog and another in the ARKH catalog. These events were excluded from the source catalogs. No additional checks were performed after merging the catalogs. According to [30; 31], a large number of seismic events registered in the Svalbard Archipelago with magnitudes ranging from 1 to 2.2 are ice-quakes. This is confirmed, among other things, by a seasonal periodicity that is not typical for earthquakes. However, in the ISC catalog, only 6 events were marked as glacial events (ice-quakes). Either the ice-quakes were cleared out by the compilers, or most of the events were still earthquakes. More than 90% of the events had a significant depth, which is not typical for ice-quakes, so we considered them earthquakes and included them in the integrated catalog (Figure S1, see Supplementary). Events with unknown magnitude/class were excluded from consideration. Earthquaves were selected within the boundaries of the studied region (Figure S2, see Supplementary). The methodology for identifying duplicates when merging catalogs is described in detail in [26]. It was successfully applied to create catalogs of the eastern and western sectors of the Russian Arctic [27; 28]. A basic three-parameter model (1) showed efficiency for assessing the proximity between earthquakes. It takes into account the time difference \(DT\), and the epicenter difference in the longitude \(DX\) and the latitude \(DY\). After that, the