Estimation of Frequencies and Splitting of 2S1 and 3S1 Modes after the 2013 Sea of Okhotsk Earthquake from IGETS Superconducting Gravimeter Network Data

For the first time, the 2 S 1 and 3 S 1 modes of the Earth’s free oscillations after the largest deep-focus earthquake in the Sea of Okhotsk on May 24, 2013 have been analyzed based on the method of maximum likelihood estimation (MLE). Data from 14 superconducting gravimeters of the IGETS network deployed in the central part of Europe are used. Estimates are obtained for the time of mode excitation relative to the earthquake origin time, degenerate frequencies, and mode splitting parameters.