The parameters of the hypocenter of the Bilimbaev earthquake that occurred on August 17, 1914, are located. We performed earthquake location based on our compilation of all available seismological bulletins of the time that included data from the ISC-GEM (International Seismological Centre–Global Earthquake Model) project, the EuroSeismos project, and the Geophysical Survey of the Russian Academy of Sciences. The location was performed using a modified generalized beamforming method based on the ak135 travel time model and regional model by the Ural region. The new epicenter is removed from the epicenters, previous-ly determined from macroseismic and partly instrumental data, at a distance not exceeding 28 km. The previously calculated earthquake epicenters are in the region of the error ellipse of the new epicenter. The depth values indicated earlier also lie in the range of possible depths of the focus of the specified hypocenter. Thus, all the epicenters, including the new one, are relevant and with equal probability can be considered as the true epicenter of the earthquake
Thanks to the new permanent seismic stations installed in the Franz Joseph Land and Severnaya Zemlya arctic archipelagoes, it has become possible at present to record earthquakes occurring in the eastern Gakkel ridge with a much lower detection threshold than that provided by the global network. At present, the lowest recorded magnitude is ML 2.4 and the magnitude of completeness is 3.4. We examined the results of seismic monitoring conducted from December 2016 through January 2020 to show that the earthquake epicenters are not uniformly distributed both in space and over time within the eastern part of the ridge. There were periods of quiescence and seismic activity. Most of the epicenters are confined to the area between 86° and 95.0° E. Relative location techniques were used to locate the single major swarm of earthquakes recorded so far. Most earthquakes were recorded by two or three stations only, so that relative location techniques have been able to yield reliable data for an analysis of the swarm. We showed that there have been actually two swarms that contained different numbers of events. The earthquakes in the larger swarm were occurring nonuniformly over time and clustered at certain depths. The ML scale was calibrated for the Eurasian Arctic based on records of the seismic stations installed in the Svalbard Archipelago, Franz Joseph Land, and on Severnaya Zemlya: −logA0(R)=1.5×logR100+1.0×10−4(R−100)+3.0. The results will help expand our knowledge of the tectonic and magmatic processes occurring within the ultraslow Gakkel ridge, which are reflected in the local seismicity.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.