IEPT RAS

Earthquakes are accompanied by postseismic processes that begin right after the main shock and are manifested in aftershocks and aseismic deformations. The main driving mechanisms of postseismic deformation are viscoelastic relaxation in the crust and in the Earth’s upper mantle and postseismic slips (afterslip), reflecting the frictional properties of the plate interface in the source zone of a large earthquake. Afterslip may occur as aftershocks and/or slow aseismic slips (creep).

In the article published in «Pure and Applied Geophysics», a modified k-nearest neighbors method is introduced, which is designed for statistically meaningful estimation of the field intensity based on locations of events. This method is used to perform a detailed analysis of the seismic intensity field in the region of Japan, shown on the figure, and found spots of increased seismic activity.

Cloaking (or “camouflage”) and illusion have long appeared in literature for children and science fiction. The “Star Trek” movies used cloaked (invisible to the enemy) spaceships (as presented in the cartoon in Fig. 1). In Charles Perrault’s Cat in Boots, a clever cat asks an ogre to turn into a little mouse and the ogre turns creating an illusion.

In the April issue of Pure and Applied Geophysics, an article on a pilot comparison of pre- and postseismic displacements associated with the most powerful earthquakes based on observations of the global positioning system GPS and networks of seismic stations appeared *.

The data of GPS stations of the Global Navigation Satellite System (GNSS) and the integral characteristics of the local seismic regime, including the accumulated displacements obtained from the catalogs of the earthquake hypocenters’ parameters before and after all mega-earthquakes – 2004 Sumatra-Andaman Mw9.2 in the Indian Ocean, 2011 off the coast of the Tohoku region Mw9.1 in Japan, 2010 on the shelf of the Maule region Mw8.8 in Chile – and the great earthquakes in Chile 2015 west of Illapel Mw8.3, in the Gulf of Alaska 2018 off Kodiak Island Mw7.9, and in New Zealand 2016 nearby the city of Kaikoura Mw7.8.

More“Displacements Before and After Great Earthquakes: Geodetic and Seismic Viewpoints”

Volcanic eruptions belong to the extreme events that change the Earth’s landscape and affect global climate and environment. Although special attention is given to super-eruptions, the non-explosive rhyolitic (highly viscous) eruptions and large lava flows are no less important. In the paper “3D Numerical Modeling of the Summit Lake Lava Flow, Yellowstone, USA”, published in Izvestiya, Physics of the Solid Earth (Q2; JIF: 0.796), an ancient lava flow in the Summit Lake region, Yellowstone is analyzed. The research conducted by scientists of IEPT RAS, IMM UB RAS, and the Lomonosov Moscow State University was supported by the Russian Science Foundation (project No. 19-17-00027).

Wiley-VCH published the article “Expansions in terms of Papkovich–Fadle eigenfunctions in the problem for a half-strip with stiffeners” in the journal Zeitschrift für Angewandte Mathematik und Mechanik (Web of Science Q3, Scopus Q2, Impact Factor JCR: 1.103). Among the authors are employees of the Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Russian Academy of Sciences (IEPT RAS): Leading Researcher, D. Sc. (Phys.-Math.) M.D. Kovalenko, Senior Researcher, Cand. Sc. (Phys.-Math.) I.V. Menshova and Senior Researcher, Cand. Sc. (Phys.-Math.) A.P. Kerzhaev.

Sage Publications published the article “An inhomogeneous problem for an elastic half-strip: An exact solution” in the journal Mathematics and Mechanics of Solids (Web of Science Q2, Scopus Q2, Impact Factor JCR: 2.040). Among the authors are employees of the Institute of Earthquake Prediction Theory and Mathematical Geophysics of the Russian Academy of Sciences (IEPT RAS): Leading Researcher, D. Sc. (Phys.-Math.) M.D. Kovalenko, Senior Researcher, Cand. Sc. (Phys.-Math.) I.V. Menshova and Senior Researcher, Cand. Sc. (Phys.-Math.) A.P. Kerzhaev.

In the article, in the form of series in Papkovich–Fadle eigenfunctions, exact solutions to two inhomogeneous boundary value problems of the theory of elasticity for a half-strip with free long sides are constructed: (1) the half-strip end is free, (2) the half-strip end is rigidly clamped. First, a solution to the inhomogeneous problem for an infinite strip is constructed. Then, the corresponding solutions for a half-strip are added to this solution, with the help of which the boundary conditions at the end are satisfied. To solve the inhomogeneous problem in a strip, the Papkovich orthogonality relation is used.