Purpous. Determination of Earth crust of transition zone Okhotsk Sea - Northern Asia influence on regional earthquakes’ and big industrial hodographs and industrial explosions. Methodology. To find out an influence of Earth crust type on earthquakes’ waves hodograph summary histograms were created: vertical component (Az), horizontal- meridional component (Ax) and latitude component (Ay). Seismic trace of sea earthquakes were tagged on negative pickets, land earthquakes – on positive pickets. Value of the picket was equal to the distance from epicenter to the station “Magadan”. Earthquakes sampling was based on few principles. First, epicenter should be located close to sub-meridional geotraverses 2DV (Koni peninsula- Vrangel Island) and 2 DV-M (Kurilsk depression – Magadan, which was studied based on GSZ-OGT methods in first decade of 20 century).Above data were used for determination of seismic characteristics of Earth crust and location of the boundaries that separate transition crust from continental one. According to the second principle, earthquakes with similar energy class K were selected for a summary seismogram. It let us get a conception of seismic waves decay behavior depending on distance between epicenter and point of observation. Third principle is based on utilizing the industrial explosions which locations can be defined with high precision. The recordings of explosions were also used for determination of hypocenter depth. Results. Based on above principles, earthquakes registered by digital equipment of MF GS RAS stations situated in transition zone Okhotsk Sea – land of Eurasia were selected. Based on that information a summary hodograph curve was created, where the placement of the station “Magadan” is set as a zero mark. Earthquakes occurred on land were tagged on the pickets within equal distance from the station “Magadan”. Picket of earthquakes occurred in waters was determined too, but it was taken as negative. Thus, the recordings of all earthquakes on land were located on the distance axis from one side of zero mark, and events occurred in waters were tagged on the other side. Orignality. A summery seismogram of earthquakes were used to determine velocities of longitudinal and transverse waves, as well as the location of the boundary between transition and continental crusts. An information required for estimation of the seismic waves decay dependency from the Earth crust types, and its influence on the dynamic characteristics of wave field were obtained for given region first time. Practical signicence. Utilization of the obtained hodograph and new information on seismic-acoustic characteristics of Earth crust improves accuracy of evaluation of the characteristics (epicenter coordinates, events’ time and their energy) of earthquakes occurred in Okhotsk Sea. As a result, accuracy of a seismic-tectonics research improves, as well as a reliability of seismic risk estimation for the Magadan region coastal zone where main population, industrial and transportation factories are located.
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