RUSSIAN CONSTRUCTION SYSTEM DOES NOT RECOGNIZE THE IMPACT OF REPEATED EARTHQUAKES ON CONSTRUCTION SITES

Today, many learned builders know that earthquakes in the territory of, for example, a settlement can manifest themselves in the form of the first most powerful earthquake (main underground shock), which is usually followed by a series of weaker repeated earthquakes (repetitive shocks). There are many examples of such a sequence of manifestations of strong earthquakes in a certain territory, when tens of thousands of people die in destroyed buildings during repeated exposure earthquakes. It is thanks to these examples that scientists, builders, understand the main cause of death due to repeated earthquakes, which is the maximum permissible degree of damage formed in buildings under the influence of the first main earthquake. In addition, many builders are aware of many examples today when the intensity of the impact of a repeated earthquake on buildings was, for a number of reasons, stronger than the intensity of the effects of a major earthquake. However, contrary to the examples of the death of thousands of people in buildings during repeated earthquakes, in the construction system of Russia, the calculation of earthquake-resistant objects continues to take into account the impact of only one main earthquake. Therefore, the article substantiates the need to take into account the effects of earthquakes and repeated earthquakes in the calculations of earthquake-resistant buildings.

The role of radiation damping in the modeling of repeated earthquake events

<p>We have investigated the role of the radiation damping term (RDT) on repeated earthquake ruptures by modeling the faulting process through a single one-dimensional analog fault system governed by different constitutive laws. The RDT expresses the energy lost by the seismic waves. The RDT is inherently accounted for in more elaborated, fully dynamic models of extended fault, whereas it is neglected in one-dimensional fault models. In this study, we adopt various formulations of the laboratory-derived rate-dependent and state-dependent friction constitutive laws: the Dieterich-Ruina law, the Ruina-Dieterich law and the Chester and Higgs law. Our numerical results clearly indicate that the RDT significantly affects the system dynamics. More specifically, the more the RDT is effective, the more frequent the slip failures are (with a cycle-time reduction of ca. 30%). We also show that inclusion of the RDT tends to promote smaller but more frequent earthquake instabilities, irrespective of the choice of the governing law. Our data shed light on the limitations implied by the conventional formulation of the equation of motion for the spring system, in which the energy radiation is ignored.</p>