# Integrated Earthquake Catalog of the Eastern Sector of the Russian Arctic
## 1 Introduction  
As is known, the Eastern Sector of the Arctic zone of the Russian Federation (AZRF) is a seismically active region [1; 2; 3; 4]. Rather strong earthquakes can occur within its limits. For example, only in the last two decades, events with magnitudes of \(M\geq 6\) have occurred there: the Olyutorsk earthquake, with \(M=7.6\), on 20 April 2006; the Ilin-Tas (Abyi) earthquake, with \(M=6.6\), on February 14 2013; the earthquake near the border of Kamchatka and Chukotka, with \(M=6.4\), on 9 January 2020; and others [5; 6; 7; 8; 9; 10]. The analysis of the seismic regime of the Arctic territories of Russia and the construction of seismic hazard maps [11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25] are topical problems today. The solution to these problems is impossible without the creation of a representative instrumental earthquake catalog [26]. The importance of these problems for the study and development of the Arctic is emphasized by the increasing level of industrial development in the region. Earthquake studies in the Eastern part of the AZRF started not so long ago. The authors of the _New Catalog of Strong Earthquakes in the U.S.S.R. from ancient times through 1977_[27], [PERSON] and [PERSON], made the first step in these studies in the late 1970s. Intensive earthquake catalog projects concerning the AZRF were implemented in the early 2000s by [PERSON] [22], [PERSON], and [PERSON], [PERSON], et al. [5, 6]. The seismic zonation map of the AZRF (as a part of the general seismic zoning map of Russian Federation) was created in recent years. At the same time, there still remains a need in the AZRF representative Eastern Sector catalog which combines data from available Russian and international sources with the magnitude reduction to a uniform scale. This paper describes the results of the study on such catalog creation. Nowadays, the seismic monitoring of the Russian Arctic is carried out by regional branches of the Geophysical Survey of the Russian Academy of Sciences (GS RAS) ([[http://www.gsras.ru/new/eng/catalog/](http://www.gsras.ru/new/eng/catalog/)]([http://www.gsras.ru/new/eng/catalog/](http://www.gsras.ru/new/eng/catalog/)), (accessed on 20 March 2022)). In the Eastern part of the Russian Arctic, this work is carried out by the Yakutsk, Magadan, and, partially, the Kamchatka Branches of the GS RAS. In addition, detailed information on earthquakes can be found in the global catalog of the International Seismological Center (ISC) ([[http://www.isc.ac.uk/isc-ehb/search/catalogue/](http://www.isc.ac.uk/isc-ehb/search/catalogue/)]([http://www.isc.ac.uk/isc-ehb/search/catalogue/](http://www.isc.ac.uk/isc-ehb/search/catalogue/)), (accessed on 20 March 2022)), which combines the data from several global and national seismological networks. It has to be noted that a comparative analysis of the catalogs showed that for the Eastern Sector of the Russian Arctic, the ISC catalog does not contain many events that are presented in the regional catalogs of the GS RAS. This is explained, among other things, by the fact that the survey reports bulletins to the ISC for events starting at a certain magnitude threshold. For this reason, the information on low-magnitude seismicity is mainly contained in regional catalogs. It should be also noted that due to the different configurations of seismic networks and methods for processing records, some agencies may skip earthquakes recorded by other networks. Thus, merging earthquake catalogs is a method for improving the completeness and representativeness of seismic events in the final catalog [28; 29; 30; 31; 32]. When merging catalogs, the problem of identifying duplicates arises. The main difficulty is discrimination [33] between aftershocks and duplicates since both of them are similar events in space and time. This problem is analogous to the discrimination between aftershocks and independent seismic events.