Problems of Engineering Seismology: article

A comment on “On earthquake depths in the Crimean-Black Sea Region” by V.E. Kulchitsky, B.G. Pustovitenko and V.A. Svidlova
V. Burmin1
L. Shumlyanskaya2
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
2 Institute of Geophysics, National Academy of Sciences of Ukraine, Kiev, Ukraine
Journal: Problems of Engineering Seismology
Tome: 44
Number: 3
Year: 2017
Pages: 103-112
UDK: 550.34
DOI: 10.21455/VIS2017.3-7
Keywords: hypocenter, algorithm, deep earthquakes, Crimea, Black Sea
Аnnotation: It is well known that the results of determining the earthquake parameters depend to a large extent on data processing algorithms and seismic wave velocity used in solving hypocenter problems. In 1992, Burmin developed a hypocentric algorithm based on minimizing the distance functional between the points corresponding to the theoretical and observed travel time of the seismic wave from the earthquake source to the recording stations. The determination of the coordinates of earthquake hypocenters in this case is much more stable than with the usual minimization of the residual time functional of the arrival of seismic waves at the station. With this algorithm and the refined velocity model of the medium, V.Yu. Burmin together with L.A. Shumlyanskaya reinterpreted the earthquake parameters in the Crimean-Black Sea region. The most important result of this reinterpretation was the conclusion that deep earthquakes with a depth of more than 60 km occurred in the region. This result contradicts the hardened ideas about the seismicity of the region and therefore caused serious criticism from experts who took an direct participation in the compilation of the existing catalogs of earthquakes in the region. These remarks and criticism are presented in the article by V.E. Kulchitsky with co-authors, published in this issue of the journal. In our article, a detailed analysis of the comments made and answers to them are provided. In particular, it was shown that the previously used methods of seismic data processing by default excluded the possibility of the appearance of deep earthquakes in the results. As an example, we refer to the use of travel time curves for depths of up to 35 km. It is quite obvious that with this approach, deep earthquakes could not be revealed.