K. A. Boyarchuk

Bio: K. A. Boyarchuk is an academic researcher from Russian Academy of Sciences. The author has contributed to research in topics: Atmosphere & Ionosphere. The author has an hindex of 7, co-authored 9 publications receiving 1255 citations.

Ionospheric precursors of earthquakes

Abstract: The Basic Components of Seismo-Ionospheric Coupling.- Ionospheric Precursors of Earthquakes as they are seen from the Ground and from Space.- Near Ground and Troposphere Plasmachemistry and Electric Field.- Physics of Seismo-Ionospheric Coupling.- Main Phenomenological Features of Ionospheric Precursors of Earthquakes.- Are we Ready for Prediction? The Practical Applications.- Ultimate Results, Unexplained Phenomena, Future Tasks.

The physical nature of thermal anomalies observed before strong earthquakes

Abstract: The paper examines the effect of air ionization on the thermal balance of the boundary layer of atmosphere. In seismically active areas the increased radon emanation from active faults and cracks before earthquakes is the primary source of air ionization. The problem is analyzed both on microscopic and macroscopic levels and in both cases the significant changes of the air relative humidity and air temperature are obtained. This happens due to the water molecules attachment to the newly formed ions (or in other words, condensation) which leads to the excretion of the latent heat. Obtained results permit us to explain the changes of the surface temperature and the surface latent heat flux increase before earthquakes observed by remote sensing satellites, as well as ground based measurements of the air temperature and relative humidity variations before the Colima earthquake (M7.6) of 2003 in Mexico, Hector Mine earthquake (M7.1) of 1999 in USA and Parkfield earthquake (M6) of 2004 in USA. These findings are also supported by the results of active experiments where the installation of artificial ionization of atmosphere is used.

Thermal, atmospheric and ionospheric anomalies around the time of the Colima M7.8 earthquake of 21 January 2003

Abstract: . The paper examines the possible relationship of anomalous variations of different atmospheric and ionospheric parameters observed around the time of a strong earthquake (Mw 7.8) which occurred in Mexico (state of Colima) on 21 January 2003. These variations are interpreted within the framework of the developed model of the Lithosphere-Atmosphere-Ionosphere coupling. The main attention is focused on the processes in the near ground layer of the atmosphere involving the ionization of air by radon, the water molecules' attachment to the formed ions, and the corresponding changes in the latent heat. Model considerations are supported by experimental measurements showing the local diminution of air humidity one week prior to the earthquake, accompanied by the anomalous thermal infrared (TIR) signals and surface latent heat flux (SLHF) and anomalous variations of the total electron content (TEC) registered over the epicenter of the impending earthquake three days prior to the main earthquake event. Statistical processing of the data of the GPS receivers network, together with various other atmospheric parameters demonstrate the possibility of an early warning of an impending strong earthquake.

The atmospheric electric field as a source of variability in the ionosphere

Abstract: Experiments have shown that the bleeding-in of a saturatedvapor of benzene does not significantly affect the PL signalrelaxation in PS (see Figs 4 and 6). This accords with theconcepts considered in Section 2. Indeed, the dielectricconstant of benzene is small and apparently the ratio of freecharge carriers to those coupled in excitons does not varysignificantly [see equation (7)]. Rather unexpectedly, at firstglance, was the effect of the change of kinetic characteristicsof PL and FCA after the filling of pores with mediumspossessing high values of e

Pre-earthquake ionospheric anomalies registered by continuous GPS TEC measurements

Abstract: . In this paper we examine pre-earthquake ionospheric anomalies by the total electron content (TEC) derived from a ground-based receiver of the Global Positioning System (GPS). A 15-day running median of the TEC and the associated inter-quartile range (IQR) are utilized as a reference for identifying abnormal signals during all of the 20M≥6.0 earthquakes in the Taiwan area from September 1999 to December 2002. Results show that the pre-earthquake ionospheric anomalies appear during 18:00–22:00LT (LT=UT+8h) within 5 days prior to 16 of the 20M≥6.0 earthquakes. This success rate of 80% (=16/20%) suggests that the GPS TEC is useful to register pre-earthquake ionospheric anomalies appearing before large earthquakes. Key words. Ionosphere (ionospheric disturbances; ionosphere-atmosphere interactions)

OPERATIONAL EARTHQUAKE FORECASTING. State of Knowledge and Guidelines for Utilization

Abstract: Following the 2009 L'Aquila earthquake, the Dipartimento della Protezione Civile Italiana (DPC), appointed an International Commission on Earthquake Forecasting for Civil Protection (ICEF) to report on the current state of knowledge of short-term prediction and forecasting of tectonic earthquakes and indicate guidelines for utilization of possible forerunners of large earthquakes to drive civil protection actions, including the use of probabilistic seismic hazard analysis in the wake of a large earthquake. The ICEF reviewed research on earthquake prediction and forecasting, drawing from developments in seismically active regions worldwide. A prediction is defined as a deterministic statement that a future earthquake will or will not occur in a particular geographic region, time window, and magnitude range, whereas a forecast gives a probability (greater than zero but less than one) that such an event will occur. Earthquake predictability, the degree to which the future occurrence of earthquakes can be determined from the observable behavior of earthquake systems, is poorly understood. This lack of understanding is reflected in the inability to reliably predict large earthquakes in seismically active regions on short time scales. Most proposed prediction methods rely on the concept of a diagnostic precursor; i.e., some kind of signal observable before earthquakes that indicates with high probability the location, time, and magnitude of an impending event. Precursor methods reviewed here include changes in strain rates, seismic wave speeds, and electrical conductivity; variations of radon concentrations in groundwater, soil, and air; fluctuations in groundwater levels; electromagnetic variations near and above Earth's surface; thermal anomalies; anomalous animal behavior; and seismicity patterns. The search for diagnostic precursors has not yet produced a successful short-term prediction scheme. Therefore, this report focuses on operational earthquake forecasting as the principle means for gathering and disseminating authoritative information about time-dependent seismic hazards to help communities prepare for potentially destructive earthquakes. On short time scales of days and weeks, earthquake sequences show clustering in space and time, as indicated by the aftershocks triggered by large events. Statistical descriptions of clustering explain many features observed in seismicity catalogs, and they can be used to construct forecasts that indicate how earthquake probabilities change over the short term. Properly applied, short-term forecasts have operational utility; for example, in anticipating aftershocks that follow large earthquakes. Although the value of long-term forecasts for ensuring seismic safety is clear, the interpretation of short-term forecasts is problematic, because earthquake probabilities may vary over orders of magnitude but typically remain low in an absolute sense (< 1% per day). Translating such low-probability forecasts into effective decision-making is a difficult challenge. Reports on the current utilization operational forecasting in earthquake risk management were compiled for six countries with high seismic risk: China, Greece, Italy, Japan, Russia, United States. Long-term models are currently the most important forecasting tools for civil protection against earthquake damage, because they guide earthquake safety provisions of building codes, performance-based seismic design, and other risk-reducing engineering practices, such as retrofitting to correct design flaws in older buildings. Short-term forecasting of aftershocks is practiced by several countries among those surveyed, but operational earthquake forecasting has not been fully implemented (i.e., regularly updated and on a national scale) in any of them. Based on the experience accumulated in seismically active regions, the ICEF has provided to DPC a set of recommendations on the utilization of operational forecasting in Italy, which may also be useful in other countries. The public should be provided with open sources of information about the short-term probabilities of future earthquakes that are authoritative, scientific, consistent, and timely. Advisories should be based on operationally qualified, regularly updated seismicity forecasting systems that have been rigorously reviewed and updated by experts in the creation, delivery, and utility of earthquake information. The quality of all operational models should be evaluated for reliability and skill by retrospective testing, and they should be under continuous prospective testing against established long-term forecasts and alternative time-dependent models. Alert procedures should be standardized to facilitate decisions at different levels of government and among the public. Earthquake probability thresholds should be established to guide alert levels based on objective analysis of costs and benefits, as well as the less tangible aspects of value-of-information, such as gains in psychological preparedness and resilience. The principles of effective public communication established by social science research should be applied to the delivery of seismic hazard information.

Seismoionospheric GPS total electron content anomalies observed before the 12 May 2008 Mw7.9 Wenchuan earthquake

Abstract: [1] The global ionospheric map (GIM) is used to observe variations in the total electron content (TEC) of the global positioning system (GPS) associated with 35 M ≥ 6.0 earthquakes that occurred in China during the 10-year period of 1 May 1998 to 30 April 2008. The statistical result indicates that the GPS TEC above the epicenter often pronouncedly decreases on day 3–5 before 17 M ≥ 6.3 earthquakes. The GPS TEC of the GIM and electron density profiles probed by six microsatellites of FORMOSAT3/COSMIC (F3/C) are further employed to simultaneously observe seismoionospheric anomalies during an Mw7.9 earthquake near Wenchuan, China, on 12 May 2008. It is found that GPS TEC above the forthcoming epicenter anomalously decreases in the afternoon period of day 6–4 and in the late evening period of day 3 before the earthquake, but enhances in the afternoon of day 3 before the earthquake. The spatial distributions of the anomalous and extreme reductions and enhancements indicate that the earthquake preparation area is about 1650 km and 2850 km from the epicenter in the latitudinal and longitudinal directions, respectively. The F3/C results further show that the ionospheric F2 peak electron density, NmF2, and height, hmF2, significantly decreases approximately 40% and descends about 50–80 km, respectively, when the GPS TEC anomalously reduces.