## Estimates of the impact frequency of cosmic bodies on the Earth

A new method of estimating the impact frequency of celestial bodies on the Earth, with corrections for the rate of crater erosion is proposed. This method is based on the content of the Expert Database on the Earth's impact structures (EDEIS) that has been developed and is being maintained in...

## Regularization of an inverse dynamic problem for the equation of SH waves in a porous medium

A regularizing algorithm of an inverse problem for a one-dimensional equation of SH waves in a fluid-saturated porous medium with energy loss under intercomponent friction is proposed.

## Conservation laws for the two-velocity hydrodynamics equations with one pressure

A series of the differential identities connecting velocities, pressure and body force in the two-velocity hydrodynamics equations with equilibrium of pressure phases are found. Some of these identities have a divergent form and can be considered to be certain conservation laws. It is detected that the flow functions for the...

## A combined inverse tsunami problem

It is known that some of the parameters required for the direct simulation of tsunamis are the bottom relief characteristics and the initial perturbation data (a tsunami source). The seismic data about the source are usually obtained in a few tens of minutes after an event has occurred (the seismic...

## Stability analysis of a continuation problem for the Helmholtz equation

We investigate the continuation problem for the elliptic equation. The continuation problem is formulated in the operator form *Aq = f*. Singular values of the operator *A* are presented and analyzed for the continuation problem for the Helmholtz equation. Results of numerical experiments are presented.

## Morphological elements of "Popigai" and other astroblemes as indicators to cosmic bodies' ballistic trajectory

In this paper, the criteria for determining a ballistic trajectory location of the Popigai cosmic body (PCB) are revised. It is concluded that this trajectory was directed not from the NE to the SW as was believed earlier, but from the SE to the NW. With this orientation, there is...

## A scale factor in the long-wave laboratory simulation

In the paper the group of variables transformation which is allowed by the shallow-water system of differential equations is obtained. During long wave simulation in water flumes it is necessary to select of the similarity coefficients, that allow to apply the results of modeling in reduced scale to real big-size...

## The gravity trace of the falling cosmic bodies trajectories

Zones of negative gravitational anomalies accompanying the Popigai and some other astroblemes (Puchezh-Katunki, Beyenchime-Salaatian, Janisjarvi, Kamensk, Karla, Kaluga, Kogram, El'gygytgyn, Wanapitei, Steinheim, Chicxulub) are considered. It is concluded that the formation of the "tails" of cosmogenic structures is associated with the energy influence of the asteroids.

## Mean value theorem for a system of differential equations for the stress tensor and pore pressure

A system of second-order differential equations for the stress tensor and pore pressure for the poroelasticity statics without mass forces and energy dissipation is obtained. The stress tensor is shown to be a biharmonic function. Integral mean value relations in the explicit form for the obtained systems of differential equations...

## Comments about the paper by Amit Kumar et al. "Displacement and stress fields in a poroelastic half-space due to a concentrated force" published in the International Journal of Engineering Science and Technology (IJEST), 2012, Vol. 4, No. 6, p. 2475-2484

The authors of paper [1] refer to papers [2, 3] by Dorovsky et al. as the source of governing equations of the poroelasticity model being studied in their paper. In papers [2, 3], according to the authors' opinion, the equations of motion of saturated porous media were obtained in terms...