Joint Perturbation in Geoacoustic Emission,Radon, Thoron,and Atmospheric Electric Field Based on Observations in Kamchatka

Izvestiya, Physics of the Solid Earth - Based on the integration and analysis of the published theoretical results and field observations, the possibility is considered of a joint perturbation in...     

Relationship of high-frequency geoacoustic emission and electric field in the atmosphere in seismotectonic process

In July–October 2006 and 2007, combined measurements of geoacoustic emission in the range of 2.0–6.5 kHz, the electric field in the atmosphere near the ground, and meteorological values were carried out in Kamchatka. Using the nonparametric method of Spearman’s correlation analysis, the relationship between their average hourly values was examined. After excluding results of bad weather (rain, strong and moderate wind, low atmospheric pressure), a highly important negative relation between disturbances in geoacoustic emission and the electric field were detected. Most probably, it was caused by amplification of the strain of near-surface sedimentary rocks at the observation point during a seismotectonic process. The revealed relation is evidence for another manifestation of the lithosphere’s influence on surface atmosphere in a seismoactive region.     

On the relation between high frequency acoustic emissions in near-surface rocks and the electric field in the near-ground atmosphere

A field instrument package was installed for synchronous measurements of acoustic emission in rocks at frequencies of 0.1–10000 Hz and the vertical gradient of electric potential in near-ground atmosphere. These investigations for the first time revealed a relationship between emission disturbances in the kilohertz frequency range due to deformation of near-surface rocks and the electric field. The relationship may be observed both during seismically quiet periods and at the final phase of earthquake precursory periods.     

Simultaneous response of high-frequency geoacoustic emission and atmospheric electric field to strain of near-surface sedimentary rocks

During the period of October 1–18, 2009, 41 km southwest of Petropavlovsk-Kamchatsky, in the intersection zone of tectonic faults of various orders, simultaneous recording of the geoacoustic emission, gradient of the atmospheric electric field’s potential, strains of the Earth’s surface, atmospheric pressure, wind speed, and rain intensity was made. It was found for the first time that anomalous disturbances of high-frequency geoacoustic emission and atmospheric electric field near the Earth’s surface originate as a simultaneous response to extension of near-surface sedimentary rocks. In the case of compression, only disturbances of geoacoustic emission occur. Anomalies were recorded under quiet weather conditions and with rocks strains being two orders greater than those of tidal ones.     

An analysis of the relationships between high-frequency geoacoustic emissions and the electrical field in the atmosphere near the ground surface

The influence of the lithosphere on the atmosphere near their interface in a seismic region was studied during summer-autumn 2006–2008 in Kamchatka by simultaneous measurements of geoacoustic emissions at frequencies of 2.0–6.5 kHz, the atmospheric electrical field at the ground surface, and meteorological quantities at a single site. We used nonparametric methods of correlation analysis to study the relationships between the mean hourly values of all the quantities concerned. After eliminating cases of bad weather, as well as identifying the weak influence of unaccounted-for meteorological and other factors in the 2006 and 2007 experiments, we found a statistically significant negative relationship between disturbances of geoacoustic emissions and those of the electrical field. The relationship is of a non-meteorological origin and is statistically not significant in the 2008 experiment. The most likely cause of this relationship consists in the activation of strain variation in near-surface sedimentary rocks around the measurement site during the seismotectonic process.