Near-seismic effects in ULF fields and seismo-acoustic emission: statistics and explanation

International audiencePreseismic intensification of fracturing has been investigated from occurrence analysis of seismo-acoustic pulses (SA foreshocks) and ULF magnetic pulses (ULF foreshocks) observed in Karimshino station in addition to seismic foreshocks. Such analysis is produced for about 40 rather strong and nearby isolated earthquakes during 2 years of recording. It is found that occurrence rate of SA foreshocks increases in the interval (-12, 0 h) before main shock with 3-times exceeding of background level in the interval (-6, -3 h), and occurrence probability of SA foreshocks (pA~75%) is higher than probability of seismic foreshocks (ps~30%) in the same time interval.ULF foreshocks are masked by regular ULF activity at local morning and daytime, nevertheless we have discovered an essential ULF intensity increase in the interval (-3, +1 h) at the frequency range 0.05-0.3 Hz. Estimated occurrence probability of ULF foreshocks is about 40%. After theoretical consideration we conclude: 1) Taking into account the number rate of SA foreshocks, their amplitude and frequency range, they emit due to opening of fractures with size of L=70-200 m (M=1-2); 2) The electro-kinetic effect is the most promising mechanism of ULF foreshocks, but it is efficient only if two special conditions are fulfilled: a) origin of fractures near fluid-saturated places or liquid reservoirs (aquifers); b) appearance of open porosity or initiation of percolation instability; 3) Both SA and ULF magnetic field pulses are related to near-distant fractures (r<20-30 km); 4) Taking into account number rate and activation period of seismic, SA and ULF foreshocks, it is rather probable that opening of fractures and rupture of fluid reservoirs occur in the large preparation area with horizontal size about 100-200km

About possibility to locate an EQ epicenter using parameters of ELF/ULF preseismic emission

A relation between parameters of preseismic ULF/ELF emissions and EQ is studied. The magnetic data measured at Karymshino station (Kamchatka, Russia) along with data on local seismic activity during eight years of observations (2001–2008) are taken for the analysis. Source azimuth is detected in different techniques, based on the analysis of the total field and its polarized pulsed component. The latter technique shows a better accuracy in the source azimuth detection. The errors of the method are associated with existence of non-seismic sources and with use of one-point observation. The second error can be eliminated by development of multi-point observations

Study of electromagnetic emissions associated with seismic activity in Kamchatka region

International audienceA review of data processing of electromagnetic emission observation collected at the Complex Geophysical Observatory Karimshino (Kamchatka peninsula) during the first 5 months (July?November, 2000) of its operation is given. The main goal of this study addresses the detection of the phenomena associated with Kamchatka seismic activity. The following observations have been conducted at CGO: variations of ULF/ELF magnetic field, geoelectric potentials (telluric currents), and VLF signals from navigation radio transmitters. The methods of data processing of these observations are discussed. The examples of the first experimental results are presented

Нейрореспираторный синдром у больных бронхиальной астмой

Personal features, cerebral bioelectrical activity, vegetative regulation, bronchial hyperreactivity and lung function regulation were analyzed in 219 bronchial asthma patients. The detected disorders allowed to characterize two-staged neuro-respiratory disadaptation syndrome. The mild disorders (the 1st stage) are described as adjusting overwork of neuro-regulatory systems. More severe disorders (the 2nd stage) are less adaptive and enhance the disease resulting in ventilation disorders and bronchial hyperreativity.У 219 больных бронхиальной астмой проанализированы особенности личности, биоэлектрической активности мозга, вегетативной регуляции, бронхиальной гиперреактивности и регуляции внешнего дыхания. Выявленные нарушения позволили выделить синдром нейрореспираторной дезадаптации, в течении которого выявлена этапность. При легком течении заболевания (первый этап) обнаружено напряжение нейрорегуляторных систем, носящее в основном адаптивный характер. При более тяжелом течении заболевания (второй этап) выявлены нарушения, которые носят не столько приспособительный характер, сколько усугубляют течение болезни и приводят к нарушению вентиляции легких и бронхиальной гиперреактивности

The functional state of endothelium at chronic hepatitis C

Aim of investigation. To study the functional state of endothelium at patients with chronic hepatitis C (CHC).Materials and methods. Forty patients with CHC in relapse phase were investigated. In all cases activity of inflammatory process was assessed, indication of НСV RNA was carried out and assessment of HCV genotype in blood serum, quantity of desquamated endotheliocytes (DEC), level of nitric oxide (NO), endothelin-1 (Et-1) and functional activity of von Willebrand factor (vWF) in blood plasma was investigated.Results. At patients of CHC elevation of DEC quantity has been registered in comparison to group of generally healthy persons (5,9±1,18·104/l and 3,02±1,2·104/l respectively, р=0,001), decrease of NO level (18,6±3,02 and 29,43±3,34 mcmol/l, р=0,001), increase of Et-1 concentration (0,7±0,21 and 0,3±0,13 fmol/l, р=0,0001) and vWF functional activity (102,1±4,75 and 80,11±2,77%, р=0,003) in blood plasma. At evaluation of dynmics of endothelial disorders during combined antiviral the rapy (AVT) studied parameters in the basic group of patients (n=10) underwent significant changes: DEC amount decreased by 35,5% from initial value, NO level increased by 35%, concentration Et-1 decreased by 63%, vWF functional activity decreased by 16% from an initial level that testifies decrease of damage activity and dysfunction of endothelium.Conclusions. At CHC there are signs of damage and dysfunction of endothelium. Combined AVT by Reaferon in combination to ribavirin at such patients is accompanied by significant improvement of endothelium functional parameters