The Global Electric Circuit and Global Seismicity

Basing on the catalogue of earthquakes with a magnitude of M ≥ 4.5 for the period 1973–2017, a UT variation with an amplitude of ~10% in the number of earthquakes is revealed and compared with a UT variation in the ionospheric potential (IP) with an amplitude of ~18%. We demonstrate that the amplitude of the UT variation in the number of deep-focus earthquakes is greater compared with that of crustal earthquakes, reaching 19%. The UT of the primary maxima of both the IP (according to modern calculations) and of earthquake incidence coincides (near 17:00 UT) and is, by 2 h, ahead of the classical Carnegie curve representing the UT variation in the atmospheric electric field on the ground surface. The linear regression equation between these UT variations in the number of deep-focus earthquakes and the ionospheric potential is obtained, with a correlation coefficient of R = 0.97. The results support the idea that the processes of earthquake preparation are coupled to the functional processes of the global electric circuit and the generation of atmospheric electric fields. In particular, the observed increase in thunderstorm activity over earthquake preparation areas, provided by air ionization due to radon emanation, yields a clue as to why the global thunderstorm distribution is primarily continental. Another important conclusion is that, in observing the longitudinal distributions of earthquakes against the IP distribution, we automatically observe that all such events occur in local nighttime hours. Considering that the majority of earthquake precursors have their maximums at local night and demonstrating the positive deviation from the undisturbed value, we obtain a clue as to its positive correlation with variations in the ionospheric potential.

Demographic and Psychological Factors and Preparation for Earthquakes

<p>New Zealand, like many countries, is at risk from a number of natural disasters including flooding, volcanoes, and earthquakes. The risk of exposure to such disasters over the course of a lifetime is substantial (Norris, 1992). Despite this, many New Zealanders are unprepared for the consequences of a natural disaster; nearly a quarter of New Zealand homes have flaws which could see them seriously damaged or detached from their foundations in a major earthquake (Ansell & Taber, 1996). Recent research suggests that psychological variables contribute to people's lack of preparation for natural disasters. A limitation, however, of much of this research has been the lack of attention paid to the psychometric quality of the instruments used to measure key constructs. The present investigation aimed to examine the relationships between different dimensions of personality and earthquake preparation in a large sample of Wellington residents using psychometrically sound measures. Measures of locus of control, risk, and earthquake preparation were first evaluated in a series of studies using both university students and Wellington residents. These questionnaires were then administered, along with items pertaining to the construct of unrealistic optimism, to a total of 358 Wellington residents. The results showed that locus of control, risk precaution, home ownership, and length of residence were significant predictors of earthquake preparation. Moreover, people exhibited evidence of unrealistic optimism, as demonstrated by both a belief that they were better prepared for a major earthquake than an acquaintance, or other Wellingtonians, and by a belief that they were personally less likely than others to suffer injury in a major earthquake. The implications of these results for emergency managers are discussed and several recommendations are made.</p>

Demographic and Psychological Factors and Preparation for Earthquakes

<p>New Zealand, like many countries, is at risk from a number of natural disasters including flooding, volcanoes, and earthquakes. The risk of exposure to such disasters over the course of a lifetime is substantial (Norris, 1992). Despite this, many New Zealanders are unprepared for the consequences of a natural disaster; nearly a quarter of New Zealand homes have flaws which could see them seriously damaged or detached from their foundations in a major earthquake (Ansell & Taber, 1996). Recent research suggests that psychological variables contribute to people's lack of preparation for natural disasters. A limitation, however, of much of this research has been the lack of attention paid to the psychometric quality of the instruments used to measure key constructs. The present investigation aimed to examine the relationships between different dimensions of personality and earthquake preparation in a large sample of Wellington residents using psychometrically sound measures. Measures of locus of control, risk, and earthquake preparation were first evaluated in a series of studies using both university students and Wellington residents. These questionnaires were then administered, along with items pertaining to the construct of unrealistic optimism, to a total of 358 Wellington residents. The results showed that locus of control, risk precaution, home ownership, and length of residence were significant predictors of earthquake preparation. Moreover, people exhibited evidence of unrealistic optimism, as demonstrated by both a belief that they were better prepared for a major earthquake than an acquaintance, or other Wellingtonians, and by a belief that they were personally less likely than others to suffer injury in a major earthquake. The implications of these results for emergency managers are discussed and several recommendations are made.</p>

Detection of Possible Short-Term Ionospheric Precursors of Strong Earthquakes Based on Changes in Diurnal Es Characteristics

The changes in two characteristics of the sporadic Е layer are studied for a pair of stations: the probability of the occurrence PEs and the limiting frequency of the ordinary wave of the sporadic E layer of the ionosphere foEs during a 10-day period of the preparation of 19 crustal earthquakes in the Pacific region with М = 6.5–7.4. The stations are located hundreds of kilometers from each other, but they fall within the zone of the preparation of a particular earthquake (the sizes of the earthquake preparation zone are estimated with formulas known in the scientific literature that relate the size of the radius of the earthquake preparation zone and the earthquake magnitude). The measurement data obtained at the ground stations of ionospheric vertical sounding are analyzed. The deviations of diurnal values of PEs (δPEs) from the median over the studied time interval and the integral diurnal values of the total irregular fluctuations in foEs (ΔfEsΣ) are used to identify possible ionospheric earthquake precursors. The coincidence of the time of appearance of the deviation maxima for both parameters before the earthquakes at each of the stations on the same day (from 1 to 4 days before the earthquake day) is recorded in the diurnal changes in the indicated values during the preparation periods of all of the considered earthquakes. The criteria for the identification of a short-term ionospheric earthquake precursor is discussed. Comparison of the analysis results for manual and automatic ionogram processing showed the prospects for the use the proposed parameters obtained according to the data of the distant ionosondes to identify the short-term ionospheric precursors of an earthquake with М = 6.5–7.0.

Two end-member earthquake preparations illuminated by foreshock activity on a meter-scale laboratory fault

The preparation process of natural earthquakes is still difficult to quantify and remains a subject of debate even with modern observational techniques. Here, we show that foreshock activity can shed light on understanding the earthquake preparation process based on results of meter-scale rock friction experiments. Experiments were conducted under two different fault surface conditions before each run: less heterogeneous fault without pre-existing gouge and more heterogeneous fault with pre-existing gouge. The results show that fewer foreshocks occurred along the less heterogeneous fault and were driven by preslip; in contrast, more foreshocks with a lower b value occurred along the more heterogeneous fault and showed features of cascade-up. We suggest that the fault surface condition and the stress redistribution caused by the ongoing fault slip mode control the earthquake preparation process, including the behavior of foreshock activity. Our findings imply that foreshock activity can be a key indicator for probing the fault conditions at present and in the future, and therefore useful for assessing earthquake hazard.

Ionosphere Sounding for Pre-seismic Anomalies Identification (INSPIRE): Results of the Project and Perspectives for the Short-Term Earthquake Forecast

The INSPIRE project was dedicated to the study of physical processes and their effects in ionosphere which could be determined as earthquake precursors together with detailed description of the methodology of ionospheric pre-seismic anomalies definition. It was initiated by ESA and carried out by an international consortium. The full set of key parameters of the ionospheric plasma was selected based on the retrospective analysis of the ground-based and satellite measurements of pre-seismic anomalies. Using this classification the multi-instrumental database of worldwide relevant ionospheric measurements (ionosonde and GNSS networks, LEO-satellites with in situ probes including DEMETER and FORMOSAT/COSMIC ROC missions) was developed for the time intervals related to selected test cases. As statistical processing shows, the main ionospheric precursors appear approximately 5 days before the earthquake within the time interval of 30 days before and 15 days after an earthquake event. The physical mechanisms of the ionospheric pre-seismic anomalies generation from ground to the ionosphere altitudes were formulated within framework of the Lithosphere-Atmosphere-Ionosphere Coupling (LAIC) model. The processes of precursor’s development were analyzed starting from the crustal movements, radon emission and air ionization, thermal and atmospheric anomalies, electric field and electromagnetic emissions generation, variations of the ionospheric plasma parameters, in particular vertical TEC and vertical profiles of the electron concentration. The assessment of the LAIC model performance with definition of performance criteria for earthquake forecasting probability has been done in statistical and numerical simulation domains of the Global Electric Circuit. The numerical simulations of the earthquake preparation process as an open complex system from start of the final stage of earthquake preparation up to the final point–main shock confirms that in the temporal domain the ionospheric precursors are one of the most late in the sequence of precursors. The general algorithm for the identification of the ionospheric precursors was formalized which also takes into account the external Space Weather factors able to generate the false alarms. The importance of the special stable pattern called the “precursor mask” was highlighted which is based on self-similarity of pre-seismic ionospheric variations. The role of expert decision in pre-seismic anomalies interpretation for generation of seismic warning is important as well. The algorithm performance of the LAIC seismo-ionospheric effect detection module has been demonstrated using the L’Aquila 2009 earthquake as a case study. The results of INSPIRE project have demonstrated that the ionospheric anomalies registered before the strong earthquakes could be used as reliable precursors. The detailed classification of the pre-seismic anomalies was presented in different regions of the ionosphere and signatures of the pre-seismic anomalies as detected by ground and satellite based instruments were described what clarified methodology of the precursor’s identification from ionospheric multi-instrumental measurements. Configuration for the dedicated multi-observation experiment and satellite payload was proposed for the future implementation of the INSPIRE project results. In this regard the multi-instrument set can be divided into two groups: space equipment and ground-based support, which could be used for real-time monitoring. Together with scientific and technical tasks the set of political, logistic and administrative problems (including certification of approaches by seismological community, juridical procedures by the governmental authorities) should be resolved for the real earthquake forecast effectuation.

The Wicked Problem of Earthquake Hazard in Developing Countries

Earthquake preparation in Bangladesh is a conundrum, where crucial information is missing and investments often involve painful trade-offs.