EGU22-7394
https://doi.org/10.5194/egusphere-egu22-7394
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Source Mechanisms of Deep Long Period Earthquakes beneath the Klyuchevskoy Volcano Group (Kamchatka, Russia) inferred from S-to-P amplitude ratios 

Natalia Galina1,2 and Nikolai Shapiro1,2
Natalia Galina and Nikolai Shapiro
  • 1Institut des Sciences de la Terre, Université Grenoble Alpes, CNRS, Grenoble, 38400 France
  • 2Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, 123242 Russia

Long-period earthquakes and tremors are one of two main classes of volcano-seismic activity. Deep long-period (DLP) earthquakes are of particular interest because usually they are attributed to the processes occurring in the deep magma reservoirs close the crust–mantle boundary. The physical mechanism of generation of these earthquakes is still not fully understood. The hypotheses of the DLPs origin include thermomechanical stresses associated with cooling of deep intrusions, rapid CO2 degassing from the oversaturated basaltic magmas, and secondary boiling.

In this work, we study the long-period earthquakes that occur at the crust-mantle boundary beneath the Klyuchevskoy volcano group in Kamchatka in order to reconstruct their source mechanism. We considered three possible sources (single force, shear slip and tensile crack) that can produce DLPs. With given hypocentral location and radiation patterns we calculated synthetic seismograms for each of assumed mechanisms. Then, we compared obtained signals with real records measuring amplitudes of P and S waves at each channel and calculating their ratios. For each of he considered types of mechanisms, we perform a grid search in the parameter space and found an optimal solution that minimizes the misfit between the observations and the model predictions.

How to cite: Galina, N. and Shapiro, N.: Source Mechanisms of Deep Long Period Earthquakes beneath the Klyuchevskoy Volcano Group (Kamchatka, Russia) inferred from S-to-P amplitude ratios , EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-7394, https://doi.org/10.5194/egusphere-egu22-7394, 2022.

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