An Asymptotically Optimal Algorithm for the Search for and Evaluation of the Slichter Mode from Long-Term Strain Data

Abstract

The Slichter mode (₁S₁) is the longest-period mode of Earth’s free oscillations. The period of this mode depends on the difference between the densities of the outer liquid and inner solid cores, thus making its detection very important for the refinement of models of the Earth. Despite numerous attempts at detecting this mode with the use of a network of superconducting gravimeters, there currently is no confirmed experimental data on the observation of the Slichter mode due to its small amplitude on the surface. In this work, it is proposed to detect the Slichter mode using the data from the laser interferometer-strainmeter of the Sternberg State Astronomical Institute of the Moscow State University (Northern Caucasus) with a measuring arm length of 75 m. For this purpose, an asymptotically optimal algorithm was developed for the analysis of data with consideration for their statistical properties, and the processing of synthetic data was modeled to estimate the magnitude of the possible observed effect and the detection indicators.