Creepex-analysis of processes in focal zones of large earthquakes by means of GIS-ENDDB

The creepex (creep & explosion) parameter provides information on the relation between low- and high-frequency radiation components in the earthquake source and has become a physically meaningful tool for analyzing various aspects of seismogenesis, in particular, the diagnostics of the preparation processes and the its aftershocks activity of a strong event. This paper investigates the spatial-temporal dynamics of creepex in the focal zones of a number of the major earthquakes from the plate convergence regions, including continental Kashmir earthquake (08.10.2005, MS=7.6) and continental-oceanic Tohoku (11.03.2011, Mw=8.7). One of the goals of this work is to demonstrate the capabilities of the method in studying physically grounded patterns of focal zones development at the first hours after the main shock. Because of this study, the following regularities of the source relaxation process were revealed: the partiality of the aftershock process, positive values of the creepex at its first hours (explained by the influence of the dilatancy process), and abrupt changes in the creepex during deep transitions (explained by the thermodynamic effect and by the increase in pressure with depth).

Thermal explosions of methyl isocyanide: a re-examination of the data

By the use of an improved interpolation method for the rate constants for the thermal isomerisation of methyl isocyanide, it is found that a pattern emerges in the previously unexplained scaling behaviour of the critical explosion parameter (δc). At low Rayleigh number (where δc should be constant) the ratio (δ/Ra)c for a fixed temperature is approximately constant for seven spherical vessels of volumes 0.3 to 5 L. Also, in the limit of very large vessels, or very high temperatures, it appears that the Arrhenius temperature coefficient of (δ/Ra)c tends to the activation energy of the reaction.

Effect of reactant consumption on the induction period and critical condition for a thermal explosion

An approximate theoretical analysis is given of a thermal explosion or ignition. The treat­ment leads to analytic expressions for the effect of reactant consumption on the critical explosion parameter and the induction period for a theoretical model, where spatial varia­tion of temperature is treated by considering only the maximum temperature at the centre of the reacting material and an effective transfer coefficient between the centre and the environment. The results are found to agree satisfactorily with detailed numerical solutions by Rice, Allen & Campbell (1935) and Todes & Melentiev (1939, 1940) where these are applicable. The effect of reactant consumption on the critical value of the explosion para­meter is shown to be more than twice that calculated by Frank-Kamenetskii (1946).