Velocity sections of the upper mantle under oceanic trenches

1Gordienko, VV
1Gordienko, LJa.
1S. I. Subbotin Institute of Geophysics of the NAS of Ukraine, Kyiv
Dopov. Nac. akad. nauk Ukr. 2016, 4:62-68
https://doi.org/10.15407/dopovidi2016.04.062
Section: Geosciences
Language: Russian
Abstract: 

According to the travel time of longitudinal waves from earthquakes in the upper mantle under oceanic trenches, a velocity model of waves beneath these structures to a depth of 360 km is developed. A sharp contrast to the distribution of Vp under the trenches of ocean regions studied earlier is found. Experimental data on the Kamchatka and Kuril trenches compiled by the authors do not allow the construction of a hodograph that would characterize such different speed sections. As a result of the selection process, the hodograph must correspond to the velocity profile different from that forming the pilot hodograph by no more than a few hundredths of km/s. In the depth interval 120–360 km, the velocity model is almost the same as the model for the mantle of a continental platform. At shallower depths, the velocity is lower, but it does not indicate the partial melting.

Keywords: earthquake, ocean trench, seismic waves, velocity model
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