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1
Rhoades, David Alan, Paul G. Somerville, Felipe Dimer de Oliveira, and Hong Kie Thio. "Effect of tectonic setting on the fit and performance of a long-range earthquake forecasting model." Research in Geophysics 2, no. 1 (February 22, 2012): 3. http://dx.doi.org/10.4081/rg.2012.e3.
Повний текст джерелаАнотація:
The Every Earthquake a Precursor According to Scale (EEPAS) long-range earthquake forecasting model has been shown to be informative in several seismically active regions, including New Zealand, California and Japan. In previous applications of the model, the tectonic setting of earthquakes has been ignored. Here we distinguish crustal, plate interface, and slab earthquakes and apply the model to earthquakes with magnitude M≥4 in the Japan region from 1926 onwards. The target magnitude range is M≥ 6; the fitting period is 1966-1995; and the testing period is 1996-2005. In forecasting major slab earthquakes, it is optimal to use only slab and interface events as precursors. In forecasting major interface events, it is optimal to use only interface events as precursors. In forecasting major crustal events, it is optimal to use only crustal events as precursors. For the smoothed-seismicity component of the EEPAS model, it is optimal to use slab and interface events for earthquakes in the slab, interface events only for earthquakes on the interface, and crustal and interface events for crustal earthquakes. The optimal model parameters indicate that the precursor areas for slab earthquakes are relatively small compared to those for earthquakes in other tectonic categories, and that the precursor times and precursory earthquake magnitudes for crustal earthquakes are relatively large. The optimal models fit the learning data sets better than the raw EEPAS model, with an average information gain per earthquake of about 0.4. The average information gain is similar in the testing period, although it is higher for crustal earthquakes and lower for slab and interface earthquakes than in the learning period. These results show that earthquake interactions are stronger between earthquakes of similar tectonic types and that distinguishing tectonic types improves forecasts by enhancing the depth resolution where tectonic categories of earthquakes are vertically separated. However, when depth resolution is ignored, the model formed by aggregating the optimal forecasts for each tectonic category performs no better than the raw EEPAS model.
2
Pulinets, Sergey, Marina Tsidilina, Dimitar Ouzounov, and Dmitry Davidenko. "From Hector Mine M7.1 to Ridgecrest M7.1 Earthquake. A Look from a 20-Year Perspective." Atmosphere 12, no. 2 (February 17, 2021): 262. http://dx.doi.org/10.3390/atmos12020262.
Повний текст джерелаАнотація:
The paper provides a comparative analysis of precursory phenomena in the ionosphere and atmosphere for two strong earthquakes of the same magnitude M7.1 that happened in the same region (North-East from Los Angeles) within a time span of 20 years, the Hector Mine and Ridgecrest earthquakes. Regardless of the similarity of their location (South-Eastern California, near 160 km one from another), there was one essential difference: the Hector Mine earthquake happened during geomagnetically disturbed conditions (essential in the sense of ionospheric precursors identification). In contrast, the quiet geomagnetic conditions characterized the period around the time of the Ridgecrest earthquake. The Hector mine earthquake happened in the middle of the rising phase of the 23-rd solar cycle characterized by high solar activity, while the Ridgecrest earthquake happened by the very end of the 24th cycle under very low solar activity conditions. We provide a comprehensive multi-factor analysis, determine the precursory period for both earthquakes and demonstrate the close similarity of ionospheric precursors. Unlike the majority of papers dealing with earthquake precursor identification based on the “abnormality” of observed time-series mainly determined by amplitude difference between “normal” (usually climatic) behavior and “abnormal” behavior with amplitudes exceeding some pre-established threshold, we used the technique of cognitive recognition of the precursors based on the physical mechanisms of their generation and the morphology of their behavior during the precursory period. These permits to uniquely identify precursors even in conditions of disturbed environment as it was around the time of the Hector Mine earthquake. We demonstrate the close similarity of precursors’ development for both events. The leading time of precursor appearance for the same region and similar magnitude was identical. For the Hector Mine it was 11 October 1999—5 days in advance—and for 2019 Ridgecrest it was 28 June—7 days before the mainshock and five days before the strongest foreshock.
3
Yusof, Khairul Adib, Mardina Abdullah, Nurul Shazana Abdul Hamid, Suaidi Ahadi, and Akimasa Yoshikawa. "Correlations between Earthquake Properties and Characteristics of Possible ULF Geomagnetic Precursor over Multiple Earthquakes." Universe 7, no. 1 (January 19, 2021): 20. http://dx.doi.org/10.3390/universe7010020.
Повний текст джерелаАнотація:
In this study, we improved and adapted existing signal processing methods on vast geomagnetic field data to investigate the correlations between various earthquake properties and characteristics of possible geomagnetic precursors. The data from 10 magnetometer stations were utilized to detect precursory ultra-low frequency emission and estimate the source direction for 34 earthquakes occurring between the year 2007–2016 in Southeast Asia, East Asia, and South America regions. As a result, possible precursors of 20 earthquakes were identified (58.82% detection rate). Weak correlations were obtained when all precursors were considered. However, statistically significant and strong linear correlations (r ≥ 0.60, p < 0.05) were found when the precursors from two closely located stations in Japan (Onagawa (ONW) and Tohno (TNO)) were exclusively investigated. For these stations, it was found that the lead time of the precursor is strongly (or very strongly) correlated with the earthquake magnitude, the local seismicity index, and the hypocentral depth. In addition, the error percentage of the estimated direction showed a strong correlation with the hypocentral depth. It is concluded that, when the study area is restricted to a specific location, the earthquake properties are more likely to have correlations with several characteristics of the possible precursors.
4
Wahyuningsih, Ulfa, Syamsurijal Rasimeng, and Karyanto Karyanto. "ANALISIS ANOMALI SINYAL ULTRA LOW FREQUENCY BERDASARKAN DATA PENGUKURAN GEOMAGNETIK SEBAGAI INDIKATOR PREKURSOR GEMPABUMI WILAYAH LAMPUNG TAHUN 2016." Jurnal Geofisika Eksplorasi 4, no. 2 (January 17, 2020): 86–101. http://dx.doi.org/10.23960/jge.v4i2.16.
Повний текст джерелаАнотація:
Regional research had been done to analysis anomalies signal of ultra low frequency based on measurement data as an indicator of the geomagnetic earthquake precursor of lampung in 2016. To achieve purpose of the study conducted by the following steps: (i) Calculation of the total magnetic field of data; (ii) Daily Trend Analysis; (iii) the Fourier transform of the data Geomagnetic Anomaly; (iv) Localization Frequency ULF; (v) Calculation of Ratio Vertical-Horizontal (Polarization Ratio Z / H); (vi) Correction magnetic storms or Disturbance Strom Time (DST); (vii) the identification of earthquake precursors; (viii) Determination of OnsetTime, leadtime,and the direction of precursors. The results of the analysis of ten earthquakes with a magnitude above 5 MW have precursors between 11 to 30 days before an earthquake. Nine out of ten earthquakes studied had an earthquake precursors and precursors that do not have, this is because the distance is too far from the station Magdas in Liwa, West Lampung. Thus it can be seen that the precursor using the magnetic data can be used to make short-term predictions.
5
Xu, Andong, Yonghong Zhao, Muhammad Irfan Ehsan, Jiaying Yang, Qi Zhang, and Ru Liu. "Inhomogeneous precursor characteristics of rock with prefabricated cracks before fracture and its implication for earthquake monitoring." Nonlinear Processes in Geophysics 28, no. 3 (August 9, 2021): 379–407. http://dx.doi.org/10.5194/npg-28-379-2021.
Повний текст джерелаАнотація:
Abstract. Earthquake precursors and earthquake monitoring are always important in the earthquake research field, even if there is still debate about the existence of earthquake precursors. However, it is extremely difficult to observe the seismogenic environment of earthquakes directly. Laboratory rupture experiment is a useful technique to simulate and gain an insight into the complex mechanisms of earthquakes. Five marble samples with prefabricated cracks are used for uniaxial loading experiments to investigate whether there is a precursory signal before rock fracture and to simulate the rupture process of strike-slip fault. The existence of a precursory signal is confirmed by the coefficient of variation (CV) results, from which we can see two patterns which are known as seismicity acceleration and quiescence before an earthquake. Moreover, these CV findings are applied to determine the locations of large deformation sampling points on the rock surface at different loading stages. Similar results are obtained when we consider actual seismicity at the northern end of the San Andreas Fault in California, which provides crucial evidence to prove the existence of precursor characteristics. In this case, three kinds of seismic monitoring models are designed to find out how to monitor these characteristics more effectively.
6
Perrone, L., L. P. Korsunova, and A. V. Mikhailov. "Ionospheric precursors for crustal earthquakes in Italy." Annales Geophysicae 28, no. 4 (April 12, 2010): 941–50. http://dx.doi.org/10.5194/angeo-28-941-2010.
Повний текст джерелаАнотація:
Abstract. Crustal earthquakes with magnitude 6.0>M≥5.5 observed in Italy for the period 1979–2009 including the last one at L'Aquila on 6 April 2009 were considered to check if the earlier obtained relationships for ionospheric precursors for strong Japanese earthquakes are valid for the Italian moderate earthquakes. The ionospheric precursors are based on the observed variations of the sporadic E-layer parameters (h'Es, fbEs) and foF2 at the ionospheric station Rome. Empirical dependencies for the seismo-ionospheric disturbances relating the earthquake magnitude and the epicenter distance are obtained and they have been shown to be similar to those obtained earlier for Japanese earthquakes. The dependences indicate the process of spreading the disturbance from the epicenter towards periphery during the earthquake preparation process. Large lead times for the precursor occurrence (up to 34 days for M=5.8–5.9) tells about a prolong preparation period. A possibility of using the obtained relationships for the earthquakes prediction is discussed.
7
Piriyev, R. H. "Effectiveness of electromagnetic monitoring in studying earthquakes." Geofizicheskiy Zhurnal 43, no. 2 (June 3, 2021): 166–77. http://dx.doi.org/10.24028/gzh.v43i2.230195.
Повний текст джерелаАнотація:
Numerous researches conducted in connection with the study of earthquakes have shown that electromagnetic monitoring studies have led to some important results. From the Loma Prieta earthquake to the Guam earthquake, electromagnetic monitoring studies led to significant results. Since then, there have been numerous reports of possible elect-romagnetic precursors to earthquakes, some of which have involved frequencies covered by ELF/VLF (10—32 kHz) monitoring system Fraser-Smith et al. [1990]. Sometime later, they retrieved and started processing their ULF data. They had less reason to expect electromagnetic precursors in this latter data, because previous reports of precursory signals at frequencies below the ELF/VLF range have, with few exceptions, involved frequencies either below or predominantly below their ULF range (0.01—10 Hz) of operation. They found out that ELF/VLF data do not appear to show precursory activity, whereas ULF data contain a number of anomalous features that may prove to be earthquake precursors. The lack of observation of precursory ELF/VLF noise so close to the epicenters of several mode-rate to moderately-large earthquakes showed that ELF/VLF noise need not be a strong or obvious feature of every earthquake, as Fraser-Smith et al. [1990] reported in their paper.
At present, numerous studies have been conducted in this area and researches are being improved. From my experience as a young researcher, it became clear that electromagnetic monitoring research is necessary, and that more important and significant results can be achieved if continuous research is conducted in a certain area. Thus, these studies may play a significant role in the detection of earthquake precursors.
8
Saradjian, M. R., and M. Akhoondzadeh. "Prediction of the date, magnitude and affected area of impending strong earthquakes using integration of multi precursors earthquake parameters." Natural Hazards and Earth System Sciences 11, no. 4 (April 19, 2011): 1109–19. http://dx.doi.org/10.5194/nhess-11-1109-2011.
Повний текст джерелаАнотація:
Abstract. Usually a precursor alone might not be useful as an accurate, precise, and stand-alone criteria for the earthquake parameters prediction. Therefore it is more appropriate to exploit parameters extracted from a variety of individual precursors so that their simultaneous integration would reduce the parameters's uncertainty. In our previous studies, five strong earthquakes which happened in the Samoa Islands, Sichuan (China), L'Aquila (Italy), Borujerd (Iran) and Zarand (Iran) have been analyzed to locate unusual variations in the time series of the different earthquake precursors. In this study, we have attempted to estimate earthquake parameters using the detected anomalies in the mentioned case studies. Using remote sensing observations, this study examines variations of electron and ion density, electron temperature, total electron content (TEC), electric and magnetic fields and land surface temperature (LST) several days before the studied earthquakes. Regarding the ionospheric precursors, the geomagnetic indices Dst and Kp were used to distinguish pre-earthquake disturbed states from the other anomalies related to the geomagnetic activities. The inter-quartile range of data was utilized to construct their upper and lower bound to detect disturbed states outsides the bounds which might be associated with impending earthquakes. When the disturbed state associated with an impending earthquake is detected, based on the type of precursor, the number of days relative to the earthquake day is estimated. Then regarding the deviation value of the precursor from the undisturbed state the magnitude of the impending earthquake is estimated. The radius of the affected area is calculated using the estimated magnitude and Dobrovolsky formula. In order to assess final earthquake parameters (i.e. date, magnitude and radius of the affected area) for each case study, the earthquake parameters obtained from different earthquake precursors were integrated. In other words, for each case study using the median and inter-quartile range of earthquake parameters, the bounds of the final earthquake parameters were defined. For each studied case, a close agreement was found between the estimated and registered earthquake parameters.
9
Eftaxias, K., Y. Contoyiannis, G. Balasis, K. Karamanos, J. Kopanas, G. Antonopoulos, G. Koulouras, and C. Nomicos. "Evidence of fractional-Brownian-motion-type asperity model for earthquake generation in candidate pre-seismic electromagnetic emissions." Natural Hazards and Earth System Sciences 8, no. 4 (July 11, 2008): 657–69. http://dx.doi.org/10.5194/nhess-8-657-2008.
Повний текст джерелаАнотація:
Abstract. Many aspects of earthquake generation still escape our full understanding. Observations of electromagnetic emissions preceding significant earthquakes provide one of the few cases of premonitory events that are possibly related to a subsequent earthquake. Understanding the factors that control electromagnetic precursors generation seems to be important for determining how significant earthquakes nucleate. Here we report the results of a comprehensive study of the appearance of individual patterns in candidate electromagnetic precursors possibly indicating the breaking of backbone of large and strong asperities that sustain the activated fault. The search of precursory patterns is mainly based on well documented scaling properties of fault surface topology. More precisely, we argue that the candidate electromagnetic precursors might be originated during the slipping of two rough and rigid fractional-Brownian-motion-type profiles one over the other, with a roughness which is consistent with field and laboratory studies. The results also imply that the activation of a single earthquake (fault) is a reduced self-affine image of the whole regional seismicity and a magnified self-affine image of the laboratory seismicity.
10
Ohsawa, Yukio. "Regional Seismic Information Entropy to Detect Earthquake Activation Precursors." Entropy 20, no. 11 (November 8, 2018): 861. http://dx.doi.org/10.3390/e20110861.
Повний текст джерелаАнотація:
A method is presented to detect earthquake precursors from time series data on earthquakes in a target region. The Regional Entropy of Seismic Information (RESI) is an index that represents the average influence of an earthquake in a target region on the diversity of clusters to which earthquake foci are distributed. Based on a simple qualitative model of the dynamics of land crust, it is hypothesized that the saturation that occurs after an increase in RESI precedes the activation of earthquakes. This hypothesis is validated by the earthquake catalog. This temporal change was found to correlate with the activation of earthquakes in Japanese regions one to two years ahead of the real activation, more reliably than the compared baseline methods.
11
Lee, Hyun A., Se-Yeong Hamm, and Nam C. Woo. "Pilot-Scale Groundwater Monitoring Network for Earthquake Surveillance and Forecasting Research in Korea." Water 13, no. 17 (September 6, 2021): 2448. http://dx.doi.org/10.3390/w13172448.
Повний текст джерелаАнотація:
Although there is skepticism about the likelihood of predictive success, research on the prediction of an earthquake through precursory changes in natural parameters, including groundwater, has continued for decades. One of the promising precursors is the changes in groundwater, i.e., the level and composition of groundwater, and the monitoring networks are currently operated to observe earthquake-related changes in several countries situated at the seismically active zone. In Korea, the seismic hazards had not been significantly considered for decades since the seismic activity was relatively low; however, the public demands on the management and prediction of earthquakes were raised by two moderate-size earthquakes which occurred in 2016 and 2017. Since then, a number of studies that were initiated in Korea, including this study to establish a pilot-scale groundwater-monitoring network, consisted of seven stations. The network is aimed at studying earthquake-related groundwater changes in the areas with relatively high potentials for earthquakes. Our study identified a potential precursory change in water levels at one particular station between 2018 and 2019. The observed data showed that most monitoring stations are sufficiently isolated from the diurnal natural/artificial activities and a potential precursory change of water level was observed at one station in 2018. However, to relate these abnormal changes to the earthquake, continuous monitoring and analysis are required as well as the aid of other precursors including seismicity and geodetic data.
12
ABDULLAEV, A. U. "PHASE REARRANGEMENT IN LOCAL BALANCED HYDROGEOCHEMICAL SYSTEMS AS A OF FLUID EARTHQUAKE PRECURSORS MECHANISM OCCURRENCE." Periódico Tchê Química 16, no. 33 (March 20, 2019): 248–58. http://dx.doi.org/10.52571/ptq.v16.n33.2019.263_periodico33_pgs_248_258.pdf.
Повний текст джерелаАнотація:
Scientists all over the world are making tremendous efforts to solve the problem of earthquake prediction. Dozens of different phenomena and signs that could serve as precursors of earthquakes are found. But these effects were very unstable and had a mosaic character in the propagation of development and time. They appeared not always and not before every major earthquake. There are many cases where earthquakes occurred without the manifestation of any precursors. Such non-stationary phenomena do not allow formulating adequate strong earthquakes preparing models and their methods of predicting. Among well-studied and encouraging earthquake precursors, hydrogeodynamic and hydrogeochemical anomalies are considered to be the most promising, which has a sufficiently substantiated scientific background. In this class of precursors, the mechanism of their formation during the preparation of earthquakes remains debatable. There are several problems due to abnormal concentration sources and their transport during a little time period in the observation points. In the proposed work, it is proved that the main mechanism of the occurrence of exotic transient fluid anomalies is the interphase rearrangement in the local balanced hydrogeochemical system as a reaction to strong earthquakes factors preparing influence. The internal phase reorganization in the hydrogeochemical system is realized through structural relaxation as a result of the occurrence of rapid physicochemical reactions exchange.
13
Lu, Kunquan, Meiying Hou, Zehui Jiang, Qiang Wang, Gang Sun, and Jixing Liu. "Understanding earthquake from the granular physics point of view — Causes of earthquake, earthquake precursors and predictions." International Journal of Modern Physics B 32, no. 07 (March 5, 2018): 1850081. http://dx.doi.org/10.1142/s0217979218500819.
Повний текст джерелаАнотація:
We treat the earth crust and mantle as large scale discrete matters based on the principles of granular physics and existing experimental observations. Main outcomes are: A granular model of the structure and movement of the earth crust and mantle is established. The formation mechanism of the tectonic forces, which causes the earthquake, and a model of propagation for precursory information are proposed. Properties of the seismic precursory information and its relevance with the earthquake occurrence are illustrated, and principle of ways to detect the effective seismic precursor is elaborated. The mechanism of deep-focus earthquake is also explained by the jamming–unjamming transition of the granular flow. Some earthquake phenomena which were previously difficult to understand are explained, and the predictability of the earthquake is discussed. Due to the discrete nature of the earth crust and mantle, the continuum theory no longer applies during the quasi-static seismological process. In this paper, based on the principles of granular physics, we study the causes of earthquakes, earthquake precursors and predictions, and a new understanding, different from the traditional seismological viewpoint, is obtained.
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Kopylova, G. N., and S. V. Boldina. "Hydrogeological precursors of earthquakes and volcanic activations according to observation data in Kamchatka Peninsula wells." Earth sciences and subsoil use 44, no. 2 (June 17, 2021): 141–50. http://dx.doi.org/10.21285/2686-9993-2021-44-2-141-150.
Повний текст джерелаАнотація:
The purpose of the study is generalization of data on the manifestations of hydrogeological earthquake precursors and volcanic activations based on long-term observations in the wells of the eastern part of the Kamchatka Peninsula. The main problem under consideration is the connection between the manifestations of hydrogeological precursors in several wells with the values of the magnitude Mw and epicentral distance of earthquakes to the wells de as well as with the parameters of seismic action in the observation area including specific density of seismic wave energy e and macroseismic intensity of shaking IMSK-64. The study results revealed that hydrogeological precursors in two-four wells had been manifesting for the period from 1 to 9 months before the strongest earthquakes with Mw = 6.6–7.8 at the epicentral distances de = 90–300 km. Such earthquakes were accompanied by the shakings of the intensity of IMSK-64 = 4–6 points. The specific density of seismic energy under such earthquakes was minimum 0.1 J/m3. The hydrogeological precursors were confined to the area for which the ratios of the earthquake epicentral distance de to the maximum linear size of the earthquake source L, km ranged from 1 to 3.7. Using the established relationships between the manifestations of hydrogeological precursors and earthquake parameters, weekly prognostic conclusions were made for expert earthquake prediction councils based on the data of current observations in wells. The well located at the distance of 15 and 20 km from the Koryaksky and Avacha active volcanoes featured the anomalous rise of groundwater pressure before the eruptions in 1991 and 2008– 2009. Therefore, a conclusion can be drawn that observation equipment operating in wells, the study results of hydrogeological precursors of earthquakes and volcanic eruptions as well as their application experience in the work of expert councils can form the scientific and technical basis for the development of geoinformation prediction technology for natural disasters in the Kamchatka Krai.
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Bhardwaj, A., L. Sam, and F. J. Martin-Torres. "The challenges and possibilities of earthquake predictions using non-seismic precursors." European Physical Journal Special Topics 230, no. 1 (January 2021): 367–80. http://dx.doi.org/10.1140/epjst/e2020-000257-3.
Повний текст джерелаАнотація:
Abstract The catastrophic magnitude of life and monetary losses associated with earthquakes deserve serious attention and mitigation measures. However, in addition to the pre-earthquake and post-earthquake alleviation actions, the scientific community indeed needs to reconsider the possibilities of earthquake predictions using non-seismic precursors. A significant number of studies in the recent decades have reported several possible earthquake precursors such as anomalies in electric field, magnetic field, gas/aerosol emissions, ionospheric signals, ground water level, land surface temperature, surface deformations, animal behaviour, thermal infrared signals, atmospheric gravity waves, and lightning. Such substantial number of scientific articles and reported anomalous signals cannot be overlooked without a thoughtful appraisal. Here, we provide an opinion on the way forward for earthquake prediction in terms of challenges and possibilities while using non-seismic precursors. A general point of concern is the widely varying arrival times and the amplitudes of the anomalies, putting a question mark on their universal applicability as earthquake markers. However, a unifying concept which does not only define the physical basis of either all or most of these anomalies but which also streamlines their characterisation procedure must be the focus of future earthquake precursory research. Advancements in developing the adaptable instrumentation for in-situ observations of the claimed non-seismic precursors must be the next step and the satellite observations should not be taken as a replacement for field-based research. We support the need to standardise the precursor detection techniques and to employ a global-scale monitoring system for making any possible earthquake predictions reliable.
16
Alekseev, O. A., S. A. Pulinets, P. A. Budnikov, V. B. Serebriakov, N. V. Razumova, and A. D. Lin’kov. "Mock-Up of Information Service for Automated Monitoring and Short-Term Forecasting of Severe Earthquakes in the Kamchatka-Sakhalin Region." Rocket-space device engineering and information systems 8, no. 4 (2021): 3–15. http://dx.doi.org/10.30894/issn2409-0239.2021.8.4.3.15.
Повний текст джерелаАнотація:
The article is devoted to the analysis of the development and control of the operation of the functional mock-up of the information service for automated monitoring and short-term forecasting of severe earthquakes in the Kamchatka-Sakhalin region. The tasks of the service mock-up concerning the collection, processing of data on earthquake precursors, the forecasting of severe (earthquake magnitude 6 or more) earthquakes in the form of estimates of the times of their onset, coordinates of epicenters (latitude and longitude) and earthquake magnitudes are determined. Taking the geoinformational character of the initial data on the approaching earthquakes as the basis for constructing the mock-up of the service, a geo-integration platform is proposed. This allows the integration of the information resources of the earthquake precursor monitoring systems, the functions of processing monitoring information into earthquake forecasts, the results of generating earthquake forecasts and their presentation to consumers into a single geoinformation environment. The composition of the service mock-up and the functioning of such elements as microservices are considered: collection and processing data from receivers of radio navigation signals of the GPS/GLONASS systems; collection and processing of data on the global distribution of TEC in the ionosphere; collection and processing of data on geomagnetic conditions, the flux of solar radio emission, thermal anomalies, as well as data concerning the atmospheric anomalies over the test site area and a unit for presenting and communicating the results of the operation of the information service mock-up for automated monitoring and short-term forecasting of severe earthquakes. The results of service operation are illustrated with the help of examples of retrospective forecasting of a number of severe earthquakes that occurred over the past 10 years in the Kamchatka-Sakhalin region, according to their precursors.
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Mignan, A., G. Ouillon, D. Sornette, and F. Freund. "Global Earthquake Forecasting System (GEFS): The challenges ahead." European Physical Journal Special Topics 230, no. 1 (January 2021): 473–90. http://dx.doi.org/10.1140/epjst/e2020-000261-8.
Повний текст джерелаАнотація:
AbstractWe conclude this special issue on the Global Earthquake Forecasting System (GEFS) by briefly reviewing and analyzing the claims of non-seismic precursors made in the present volume, and by reflecting on the current limitations and future directions to take. We find that most studies presented in this special volume, taken individually, do not provide strong enough evidence of non-seismic precursors to large earthquakes. The majority of the presented results are hampered by the fact that the task at hand is susceptible to potential biases in data selection and possible overfitting. The most encouraging results are obtained for ground-based geoelectric signals, although the probability gain is likely small compared to an earthquake clustering baseline. The only systematic search on satellite data available so far, those of the DEMETER mission, did not find a robust precursory pattern. The conclusion that we can draw is that the overall absence of convincing evidence is likely due to a deficit in systematically applying robust statistical methods and in integrating scientific knowledge of different fields. Most authors are specialists of their field while the study of earthquake precursors requires a system approach combined with the knowledge of many specific characteristics of seismicity. Relating non-seismic precursors to earthquakes remains a challenging multidisciplinary field of investigation. The plausibility of these precursors predicted by models of lithosphere-atmosphere-ionosphere coupling, together with the suggestive evidence collected here, call for further investigations. The primary goal of the GEFS is thus to build a global database of candidate signals, which could potentially improve earthquake predictability (if the weak signals observed are real and false positives sufficiently uncorrelated between different data sources). Such a stacking of disparate and voluminous data will require big data storage and machine learning pipelines, which has become feasible only recently. This special issue compiled an eclectic list of non-seismic precursor candidates, which is in itself a valuable source of information for seismologists, geophysicists and other scientists who may not be familiar with such types of investigations. It also forms the foundation for a coherent, multi-disciplinary collaboration on earthquake prediction.
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Bornyakov, S. A., D. V. Salko, and G. V. Vstovsky. "Methodology of Rock Deformation Monitoring in Southern Baikal Region." Bulletin of Irkutsk State University. Series Earth Sciences 38 (2021): 13–40. http://dx.doi.org/10.26516/2073-3402.2021.38.13.
Повний текст джерелаАнотація:
The Southern Baikal region is located within the limits of the actively developing Baikal rift zone (BRZ). Its seismic potential is significant, and M>7 earthquakes occur periodically with intensive shaking in the epicenters (up to 10 points). The problem of prediction and forecasting of strong earthquakes has always been critical for this region, considering its increasing urbanization, industrial clusters and transport systems. The article describes the methodology based on rock deformation monitoring data, which aims at developing a technology capable of efficient prediction and forecasting of strong earthquakes. The technology is based on the stick-slip model developed by of W. Brace and J. Byerlee and its synergetic interpretation proposed by Ma J. et al. This model shows the preparation of the earthquake source in stages, which is reflected in deformation monitoring data. An integral property of the deformation process is its self-organization right before an earthquake. The self-organization, that always takes place before a seismic event, is considered by the authors as an inevitable shortterm precursor. All other indicators that occur randomly are considered occasional precursors. The article is focused on the methodology aspects and describes the technical details of measuring the rock deformation. It presents the proven methods of data processing with the major goal of detecting the inevitable precursor. Described in detail are the structural-geodynamic conditions of the locations of rock deformation monitoring points in the study area. The main results are based on the rock deformation records taken before three strong earthquakes in the study area – Kultuk (August 27, 2008), Bystrinskoe (September 21, 2020), and Kudara (December 10, 2020) earthquakes. The study shows that, in contrast to the inevitable precursor, the occasional precursors are manifested depending on the geodynamic conditions of the earthquake source preparation, the position of the monitoring point relative to the source, and the structural conditions of the monitoring point location.
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Piriyev, R. "REVIEW OF ELECTROMAGNETIC MONITORING STUDIES IN PREDICTING EARTHQUAKES: RECENT RESULTS AND NEW PERSPECTIVES." Visnyk of Taras Shevchenko National University of Kyiv. Geology, no. 1(96) (2022): 40–45. http://dx.doi.org/10.17721/1728-2713.96.06.
Повний текст джерелаАнотація:
In order to make comparisons and find new perspectives in terms of electromagnetic phenomena in earthquake prediction, ULF range was chosen. For comparison, tables consisting of the results of studies from previous years and the last 10 years have been compiled. In order to find new perspectives, the graphs were drawn and comparative analysis was carried out on the basis of these results. It was concluded that the ULF precursors can be found before earthquakes reaching up to 30 km in depth, and it can be considered a promising effective range in detecting precursors of earthquakes. In addition, due to the connection between the epicenter distances and the depths of the earthquakes and their magnitudes, attempts to detect the precursors have been made so that the epicenter of the earthquakes is ±100km. The article also provides information about ULF networks and about researchers who had critical opinions on electromagnetic phenomena associated with earthquakes.
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Bogdanov, Vadim, and Aleksey Pavlov. "Development of a methodology to estimate a region and waiting period for strong Kamchatka earthquakes based on seismic and ionospheric predictive signs." E3S Web of Conferences 127 (2019): 03002. http://dx.doi.org/10.1051/e3sconf/201912703002.
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In this paper, an attempt is made to combine seismological and ionospheric predictive signs formed on the eve of earthquakes in order to develop a methodology for assessing the region and the time period of waiting for strong Kamchatka earthquakes with energy class KS ≥ 13:5 (M ≥ 6:0). The seismological parameter determined on the basis of the probabilistic model of the seismicity of Kamchatka region and allowing to estimate the region and the probability of occurrence of a strong earthquake in it is proposed as a mediumterm precursor. The complex of ionospheric disturbances is considered as a short-term precursor with a waiting period of up to 5 days for earthquakes. The estimation of their prognostic efficiency for the considered precursors is carried out by methods A. A. Gusev and G. M. Molchan, and their joint analysis was performed on the eve of earthquakes with KS ≥ 13:5 (M ≥ 6:0), that occurred in the period 2009–2018.
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Buchachenko, Anatolii L., V. N. Oraevskii, O. A. Pokhotelov, Valerii M. Sorokin, V. N. Strakhov, and V. M. Chmyrev. "Ionospheric precursors to earthquakes." Uspekhi Fizicheskih Nauk 166, no. 9 (1996): 1023. http://dx.doi.org/10.3367/ufnr.0166.199609g.1023.
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Buchachenko, Anatolii L., Viktor N. Oraevskii, O. A. Pokhotelov, Valerii M. Sorokin, V. N. Strakhov, and V. M. Chmyrev. "Ionospheric precursors to earthquakes." Physics-Uspekhi 39, no. 9 (September 30, 1996): 959–65. http://dx.doi.org/10.1070/pu1996v039n09abeh001550.
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Kedar, Sharon, and Hiroo Kanamori. "Continuous monitoring of seismic energy release associated with the 1994 Northridge earthquake and the 1992 Landers earthquake." Bulletin of the Seismological Society of America 86, no. 1A (February 1, 1996): 255–58. http://dx.doi.org/10.1785/bssa08601a0255.
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Abstract We have developed a method to detect long-period precursors for large earthquakes observed in southern California, if they occur. The method allows us to continuously monitor seismic energy radiation over a wide frequency band to investigate slow deformation in the crust (e.g., slow earthquakes), especially before large earthquakes. We used the long-period records (1 sample/sec) from TERRAscope, a broadband seismic network in southern California. The method consists of dividing the record into a series of overlapping 30-min-long windows, computing the spectra over a frequency band of 0.00055 to 0.1 Hz, and plotting them in the form of a time-frequency diagram called spectrogram. This procedure is repeated daily over a day-long record. We have analyzed the 17 January 1994 Northridge earthquake (Mw = 6.7), and the 28 June 1992 Landers earthquake (Mw = 7.3). No slow precursor with spectral amplitude measured over a duration of 30 min larger than that of a magnitude 3.7 was detected prior to either event. In other words, there was no precursor whose moment was larger than ∼0.003% of the mainshock.
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Yao, Xiuyi, Wanqing Wang, and Yuntian Teng. "Detection of Geomagnetic Signals as Precursors to Some Earthquakes in China." Applied Sciences 12, no. 3 (February 6, 2022): 1680. http://dx.doi.org/10.3390/app12031680.
Повний текст джерелаАнотація:
Extracting weak seismic-magnetic signals from strong electromagnetic backgrounds has always been an important part of seismic-electromagnetic research. Based on the data of D/H/Z components measured through a three-axis ring-core-type fluxgate magnetometer in GLM (Geermu), JYG (Jiayuguan), and KSH (Kashi) observatories, we analyzed geomagnetic signals as precursors to some earthquakes in China using the polarization method. The most effective main frequency of seismic-electromagnetic emission was determined according to the skin effect. The results showed that only 5 out of 37 earthquakes were found to have probable signals of seismomagnetic anomalies before them. Further research revealed that the significant enhancements of polarization ratios of YZH and YZG (YZH, the spectral power ratio of Z to H and YZG, the spectral power ratio of Z to G) occurred five days prior to the Jinta earthquake (Ms 5.4) and continued for about two months. The polarization ratio of YZH reached an abnormally high value about one month before some earthquakes (Ms 7.4, Ms 6.7, Ms 6.7) near the KSH station and lasted for about one week to half a month, then returned to the normal value. Similarly, some enhancements of polarization ratios of YZH and YZG occurred two months before the Haixi earthquake (Ms 5.0) and lasted for about one month. Analysis results showed that the enhancements prior to earthquake events may be closely related to the Jinta earthquake and a series of earthquakes near the KSH station; however, the high value of YZH and YZG in GLM station had nothing to do with the Haixi earthquake.
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Korsunova, L. P., and A. D. Legen’ka. "Detection of Possible Short-Term Ionospheric Precursors of Strong Earthquakes Based on Changes in Diurnal Es Characteristics." Geomagnetism and Aeronomy 61, no. 6 (November 2021): 896–904. http://dx.doi.org/10.1134/s0016793221050066.
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Abstract 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.
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Lin, Jyh-Woei. "Latitude-Time Total Electron Content Anomalies as Precursors to Japan's Large Earthquakes Associated with Principal Component Analysis." International Journal of Geophysics 2011 (2011): 1–12. http://dx.doi.org/10.1155/2011/763527.
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The goal of this study is to determine whether principal component analysis (PCA) can be used to process latitude-time ionospheric TEC data on a monthly basis to identify earthquake associated TEC anomalies. PCA is applied to latitude-time (mean-of-a-month) ionospheric total electron content (TEC) records collected from the Japan GEONET network to detect TEC anomalies associated with 18 earthquakes in Japan () from 2000 to 2005. According to the results, PCA was able to discriminate clear TEC anomalies in the months when all 18 earthquakes occurred. After reviewing months when no earthquakes occurred but geomagnetic storm activity was present, it is possible that the maximal principal eigenvalues PCA returned for these 18 earthquakes indicate earthquake associated TEC anomalies. Previously PCA has been used to discriminate earthquake-associated TEC anomalies recognized by other researchers, who found that statistical association between large earthquakes and TEC anomalies could be established in the 5 days before earthquake nucleation; however, since PCA uses the characteristics of principal eigenvalues to determine earthquake related TEC anomalies, it is possible to show that such anomalies existed earlier than this 5-day statistical window.
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Boudriki Semlali, Badr-Eddine, Carlos Molina, Hyuk Park, and Adriano Camps. "First Results on the Systematic Search of Land Surface Temperature Anomalies as Earthquakes Precursors." Remote Sensing 15, no. 4 (February 17, 2023): 1110. http://dx.doi.org/10.3390/rs15041110.
Повний текст джерелаАнотація:
Every year, earthquakes cause thousands of casualties and high economic losses. For example, in the time frame from 1998 to 2018, the total number of casualties due to earthquakes was larger than 846 thousand people, and the recorded economic losses were about USD 661 billion. At present, there are no earthquake precursors that can be used to trigger a warning. However, some studies have analyzed land surface temperature (LST) anomalies as a potential earthquake precursor. In this study, a large database of global LST data from the Geostationary Operational Environmental Satellite (GOES) and AQUA satellites during the whole year 2020 has been used to study the LST anomalies in the areas affected by earthquakes. A total of 1350 earthquakes with a magnitude larger than M4 were analyzed. Two methods widely used in the literature have been used to detect LST anomalies in the detrended LST time series: the interquartile (IQT) method and the standard deviation (STD). To the authors’ knowledge, it is the first time that the confusion matrix (CM), the receiver operating characteristic curve (ROC), and some other figures of merit (FoM) are used to assess and optimize the performance of the methods, and to select the optimum combination that could be used as a proxy for their occurrence. A positive anomaly was found a few days before the studied earthquakes, followed by the LST decrease after the event. Further studies over larger regions and more extended periods will be needed to consolidate these encouraging results.
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Whitehead, N. E., U. Ulusoy, H. Asahara, and M. Ikeya. "Are any public-reported earthquake precursors valid?" Natural Hazards and Earth System Sciences 4, no. 3 (July 27, 2004): 463–68. http://dx.doi.org/10.5194/nhess-4-463-2004.
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Abstract. This article examines retrospective public-supplied precursor reports statistically, and confirms published hypotheses that some alleged precursors within 100km and within a day prior to the large 1995 Kobe and 1999 Izmit earthquakes, may be valid. The confirmations are mostly at the p<0.001 level of significance. Most significant were alleged meteorological and geophysical precursors, and less often, animal reports. The chi-squared test used, for the first time eliminates the distorting effects of psychological factors on the reports. However it also shows that correct reports are diluted with about the same number which are merely wishful thinking, and obtaining more reliable data would be logistically difficult. Some support is found for another published hypothesis in which other precursors occurred within the ten days prior to the earthquake.
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Eftaxias, K., P. Kapiris, J. Polygiannakis, A. Peratzakis, J. Kopanas, G. Antonopoulos, and D. Rigas. "Experience of short term earthquake precursors with VLF–VHF electromagnetic emissions." Natural Hazards and Earth System Sciences 3, no. 3/4 (August 31, 2003): 217–28. http://dx.doi.org/10.5194/nhess-3-217-2003.
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Abstract. Electromagnetic anomalies (EMA) covering a wide range of frequencies from ULF, VLF up to VHF have been observed before recent destructive earthquakes in continental Greece. We show that the features of these signals are possibly correlated with the fault model characteristics of the associated earthquake and with the degree of geotectonic heterogeneity within the focal zone. The time evolution of these electromagnetic sequences reveals striking similarities to that observed in laboratory acoustic and electromagnetic emissions during different stages of failure preparation process in rocks. If we consider that the same dynamics governs the large-scale earthquakes and the microscopic scale sample rheological structure, the results of this analysis suggest that the recorded EMA might reflect the nucleation phase of the associated impending earthquake. We focus on the rise of the statistical view of earthquakes. We find electro-magnetic fingerprints of an underlying critical mechanism. Finally, we conclude that it is useful to combine ULF and VLF-VHF field measurements in an attempt to enhance the understanding of the physics behind these observations and thus to improve the quality of earthquake prediction. Further, the identification of an EMA as a seismogenic one supports the characterization of a sequence of shocks as foreshocks at the time they occur, further helping the earthquake prediction effort.
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Zhou, Zhihua, Jun Zhong, Jing Zhao, Rui Yan, Lei Tian, and Hong Fu. "Two Mechanisms of Earthquake-Induced Hydrochemical Variations in an Observation Well." Water 13, no. 17 (August 30, 2021): 2385. http://dx.doi.org/10.3390/w13172385.
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Due to frequent large earthquakes in the Lanping-Simao fault basin—located in China’s Yunnan Province—the Simao observation well has observed groundwater discharge, as well as Ca2+, Mg2+, and HCO3− concentrations every day between 2001–2018. Over 18 years of observations, M ≥ 5.6 earthquakes within a radius of 380 km from the well were seen to cause hydrochemical variations. In this study, we investigated CO2 release and groundwater mixing as possible causes of regional earthquake precursors, which were caused by the characteristics of the regional structure, lithology, water-rock reactions, and a GPS velocity field. Precursory signals due to CO2 injection are normally short-term changes that take two months. However, groundwater mixing linked to earthquakes was found to take, at the earliest, 15 months. The proportion of shallow water that contributes to mixing was found to significantly increase gradually with the stronger regional strain. These finding delineate the two mechanisms of earthquake-induced hydrochemical variations in an observation well, and would contribute to a better understanding of chemical changes before events in the Simao basin.
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Zotov, O. D., A. V. Guglielmi, and A. L. Sobisevich. "On magnetic precursors of earthquakes." Izvestiya, Physics of the Solid Earth 49, no. 6 (November 2013): 882–89. http://dx.doi.org/10.1134/s1069351313050145.
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Park, Stephen K. "Precursors to earthquakes: Seismoelectromagnetic signals." Surveys in Geophysics 17, no. 4 (July 1996): 493–516. http://dx.doi.org/10.1007/bf01901642.
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Ruzhin, Yuri, and Costas Nomicos. "Radio VHF Precursors of Earthquakes." Natural Hazards 40, no. 3 (November 22, 2006): 573–83. http://dx.doi.org/10.1007/s11069-006-9021-1.
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Asaly, Saed, Lee-Ad Gottlieb, Nimrod Inbar, and Yuval Reuveni. "Using Support Vector Machine (SVM) with GPS Ionospheric TEC Estimations to Potentially Predict Earthquake Events." Remote Sensing 14, no. 12 (June 12, 2022): 2822. http://dx.doi.org/10.3390/rs14122822.
Повний текст джерелаАнотація:
There are significant controversies surrounding the detection of precursors that may precede earthquakes. Natural hazard signatures associated with strong earthquakes can appear in the lithosphere, troposphere, and ionosphere, where current remote sensing technologies have become valuable tools for detecting and measuring early warning signals of stress build-up deep in the Earth’s crust (presumably associated with earthquake events). Here, we propose implementing a machine learning support vector machine (SVM) technique, applied with GPS ionospheric total electron content (TEC) pre-processed time series estimations, to evaluate potential precursors caused by earthquakes and manifested as disturbances in the TEC data. After filtering and screening our data for solar or geomagnetic influences at different time scales, our results indicate that for large earthquakes (>Mw 6), true negative predictions can be achieved with 85.7% accuracy, and true positive predictions with an accuracy of 80%. We tested our method with different skill scores, such as accuracy (0.83), precision (0.85), recall (0.8), the Heidke skill score (0.66), and true skill statistics (0.66).
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Zhuang, Jiancang, Mitsuhiro Matsu’ura, and Peng Han. "Critical zone of the branching crack model for earthquakes: Inherent randomness, earthquake predictability, and precursor modelling." European Physical Journal Special Topics 230, no. 1 (January 2021): 409–24. http://dx.doi.org/10.1140/epjst/e2020-000272-7.
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Abstract The branching crack model for earthquakes was developed by Vere-Jones and Kagan in the 1970s and the 1980s, respectively. With some simple and rational assumptions, its simulation results explain the Gutenberg-Richter magnitude-frequency relationship and the Omori-Utsu aftershock decay formula. By introducing the concept of the critical zone, this model can be connected with the asperity model, the barrier model, and the nucleation model through a parameter – criticality. Particularly, the size of the critical zone determines the maximum magnitude of potential earthquakes and the source of their anomalies. The key to earthquake forecasting is to determine whether the concerned area is in a critical state and how large the critical zone is. We discuss what kinds of anomalies are meaningful as candidates of earthquake precursors. Finally, we outline modelling strategies for earthquake precursors with low probability gains that are due to the inherent randomness of earthquake source processes.
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Singh, Ramesh P., Guido Cervone, Vijay P. Singh, and Menas Kafatos. "Generic precursors to coastal earthquakes: Inferences from Denali fault earthquake." Tectonophysics 431, no. 1-4 (February 2007): 231–40. http://dx.doi.org/10.1016/j.tecto.2006.05.040.
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Kopylova, G. N., Sh S. Yusupov, Yu K. Serafimova, L. Yu Shin, and S. V. Boldina. "HYDROGEOCHEMICAL EARTHQUAKE PRECURSORS (ON THE EXAMPLE OF AREAS OF THE KAMCHATKA PENINSULA, RUSSIA, AND THE REPUBLIC OF UZBEKISTAN)." Bulletin of Kamchatka Regional Association «Educational-Scientific Center». Earth Sciences 4(48) (2020): 5–20. http://dx.doi.org/10.31431/1816-5524-2020-4-48-5-20.
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Hydrogeochemical precursors of the earthquakes (HGCP) in changes of ion-salt and gas composition of underground waters from self-discharging wells and springs on the territory of Petropavlovsk-Kamchatsky test site, Kamchatka Peninsula, Russia and Tashkent test site, Republic of Uzbekistan are considered. There has been analyzed the connection of HGCP with parameters of earthquakes — with correlation between magnitudes and epicentral distances, as well as with values of specific density of seismic energy in the wave, intensity of ground shaking and other parameters of earthquake impact in the regions of observation. In Kamchatka wells HGCP were revealed before the earthquakes with Mw = 6.5 to 7.8 at epicentral distances de = 100 to 310 km at relatively narrow ranges of values of seismic energy density in the wave (0.1 to 0.3 J/m3), volumetric coseismic deformation of water-containing rocks (one to tens 10-9) and maximal velocities of seismic waves (3.5–7.7 cm/sec). HGCP took place in the zones with intensity of the earthquakes not less than 4 to 6 by MSK-64 scale and were confined to the intermediate zones of sources of future earthquakes. Duration of HGCP development and their appearance before the following earthquakes amount to 1 to 9 months, which allows using such precursors for prediction of time of strong earthquakes.
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Mullayarov, V. A., V. V. Argunov, L. M. Abzaletdinova, and V. I. Kozlov. "Ionospheric effects of earthquakes in Japan in March 2011 obtained from observations of lightning electromagnetic radio signals." Natural Hazards and Earth System Sciences 12, no. 10 (October 23, 2012): 3181–90. http://dx.doi.org/10.5194/nhess-12-3181-2012.
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Abstract. Manifestations of disturbances in the lower ionosphere caused by a complex series of earthquakes (the strong earthquakes with M = 7.3 and M = 9 – known as M9 Tohoku EQ – and the subsequent aftershocks) that occurred near the Japanese island of Honshu have been considered with the use of monitoring measurements of the amplitude of lightning electromagnetic signals (atmospherics) received at Yakutsk. Some data of one-point lightning location systems have been compared with the data of the WWLLN network. The analysis of hourly values variation of the atmospheric amplitude passing over the earthquake epicenters shows that during the initial period (the strong earthquakes on 9 March and 11 March) a typical pattern of variations was observed. It was manifested in the increased amplitude after both earthquakes. There were also possible precursors in the form of the increase in amplitude 12–14 days before the events. Though the focuses of these earthquakes were very close to each other, the registration of both precursors may indicate that both of the lithospheric processes developed to a certain extent independently. During all the days of the atmospheric amplitude enhancement the quasi-periodic variation trains were recorded. Together with the delay of earthquake effects relative to the time of the events, they may testify in favor of transferring the energy of lithospheric processes into the lower ionosphere by means of atmospheric gravity waves.
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Kachakhidze, M., N. Kachakhidze, R. Kiladze, V. Kukhianidze, and G. Ramishvili. "Relatively small earthquakes of Javakheti Highland as the precursors of large earthquakes occuring in the Caucasus." Natural Hazards and Earth System Sciences 3, no. 3/4 (August 31, 2003): 165–70. http://dx.doi.org/10.5194/nhess-3-165-2003.
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Abstract. Javakheti Highland is one of the most seismic active regions of the Caucasus. The majority of earthquakes observed throughout the region occur within this small area (f = 40.8° – 41.8° ; l = 43.3° – 44.3°). One can expect that exclusive seismic activity of Javakheti Highland testifies to global geophysical processes which take place throughout the Caucasus region. Based on the above-mentioned, of interest was to study variation with time of the number of earthquakes occurring in Javakheti region. We analysed some 695 relatively small earthquakes (2.5 < M < 6.0) observed in Javalkheti Highland within the period of 1961–1992 with regard to large earthquakes M > 6.0 of the region which occurred in the same period. It was found that each large earthquake of the Caucasus is anticipated by clear precursor in a form of an anomalous change in the number of relatively small earthquakes in Javakheti Highland.
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DeSalvio, Nicolas D., and Maxwell L. Rudolph. "A Retrospective Analysis of b-Value Changes Preceding Strong Earthquakes." Seismological Research Letters 93, no. 1 (October 6, 2021): 364–75. http://dx.doi.org/10.1785/0220210149.
Повний текст джерелаАнотація:
Abstract Earthquake precursors have long been sought as a means to predict earthquakes with very limited success. Recently, it has been suggested that a decrease in the Gutenberg–Richter b-value after a magnitude 6 earthquake is predictive of an imminent mainshock of larger magnitude, and a three-level traffic-light system has been proposed. However, this method is dependent on parameters that must be chosen by an expert. We systematically explore the parameter space to find an optimal set of parameters based on the Matthews correlation coefficient. For each parameter combination, we analyze the temporal changes in the frequency–magnitude distribution for every M ≥ 6 earthquake sequence in the U.S. Geological Survey Comprehensive Earthquake Catalog for western North America. We then consider smaller events, those with a foreshock magnitude as small as 5, and repeat the analysis to assess its performance for events that modify stresses over smaller spatial regions. We analyze 25 M ≥ 6 events and 88 M 5–6 events. We find that no perfect parameter combination exists. Although the method generates correct retrodictions for some M 5 events, the predictions are dependent on the retrospectively selected parameters. About 80%–95% of magnitude 5–6 events have too little data to generate a result. Predictions are time dependent and have large uncertainties. Without a precise definition of precursory b-value changes, this and similar prediction schemes are incompatible with the IASPEI criteria for evaluating earthquake precursors. If limitations on measuring precursory changes in seismicity and relating them to the state of stress in the crust can be overcome, real-time forecasting of mainshocks could reduce the loss of lives.
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Akhoondzadeh, Mehdi, and Dedalo Marchetti. "Developing a Fuzzy Inference System Based on Multi-Sensor Data to Predict Powerful Earthquake Parameters." Remote Sensing 14, no. 13 (July 4, 2022): 3203. http://dx.doi.org/10.3390/rs14133203.
Повний текст джерелаАнотація:
Predicting the parameters of upcoming earthquakes has always been one of the most challenging topics in studies related to earthquake precursors. Increasing the number of sensors and satellites and consequently incrementing the number of observable possible earthquake precursors in different layers of the lithosphere, atmosphere, and ionosphere of the Earth has opened the possibility of using data fusion methods to estimate and predict earthquake parameters with low uncertainty. In this study, a Mamdani fuzzy inference system (FIS) was proposed and implemented in five case studies. In particular, the magnitude of Ecuador (16 April 2016), Iran (12 November 2017), Papua New Guinea (14 May 2019), Japan (13 February 2021), and Haiti (14 August 2021) earthquakes were estimated by FIS. The results showed that in most cases, the highest number of anomalies was usually observed in the period of about one month before the earthquake and the predicted magnitude of the earthquake in these periods was slightly different from the actual magnitude value. Therefore, based on the results of this study, it could be concluded that if a significant number of anomalies are observed in the time series of different precursors, it is likely that an earthquake of the magnitude predicted by the proposed FIS system within the Dobrovolsky area of the studied location will happen during the next month.
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Chen, Li Ping, Xiang Zeng Kong, Pan Xiong, Jing Zeng, Xin Qi Lin, Zhi Zheng, and Xiao Shan Zhan. "The Application of Cumulative Sum Feature Extraction Algorithm in Data Stream Anomaly Analysis before Earthquake." Advanced Materials Research 765-767 (September 2013): 524–27. http://dx.doi.org/10.4028/www.scientific.net/amr.765-767.524.
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A cumulative sum feature extraction algorithm for anomaly analysis before earthquake is proposed by using the cumulative sum feature extraction algorithm. The analysis results reveal that the anomalous variations exist prior to the earthquakes. The methods studied in this work include cumulative sum, smooth using the Technology of Locally weighted smoothing and compute feature points. These methods have been applied to analyze the anomaly from OLR data that correspond to seismic precursors, particularly to a comparative study of the two earthquakes of Wenchuan in China and one earthquake in eastern Japan.
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Zhang, Ying, and Qingyan Meng. "A statistical analysis of TIR anomalies extracted by RSTs in relation to an earthquake in the Sichuan area using MODIS LST data." Natural Hazards and Earth System Sciences 19, no. 3 (March 15, 2019): 535–49. http://dx.doi.org/10.5194/nhess-19-535-2019.
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Abstract. Research in the field of earthquake prediction has a long history, but the inadequacies of traditional approaches to the study of seismic threats have become increasingly evident. Remote sensing and Earth observation technology, an emerging method that can rapidly capture information concerning anomalies associated with seismic activity across a wide geographic area, has for some time been believed to be the key to overcoming the bottleneck in earthquake prediction studies. However, a multi-parametric method appears to be the most promising approach for increasing the reliability and precision of short-term seismic hazard forecasting, and thermal infrared (TIR) anomalies are important earthquake precursors. While several studies have investigated the correlation among TIR anomalies identified by the robust satellite techniques (RSTs) methodology and single earthquakes, few studies have extracted TIR anomalies over a long period within a large study area. Moreover, statistical analyses are required to determine whether TIR anomalies are precursors to earthquakes. In this paper, RST data analysis and the Robust Estimator of TIR Anomalies (RETIRA) index were used to extract the TIR anomalies from 2002 to 2018 in the Sichuan region using Moderate Resolution Imaging Spectroradiometer (MODIS) land surface temperature (LST) data, while the earthquake catalog was used to ascertain the correlation between TIR anomalies and earthquake occurrences. Most TIR anomalies corresponded to earthquakes, and statistical methods were used to verify the correlation between the extracted TIR anomalies and earthquakes. This is the first time that the ability to predict earthquakes has been evaluated based on the positive predictive value (PPV), false discovery rate (FDR), true-positive rate (TPR), and false-negative rate (FNR). The statistical results indicate that the prediction potential of RSTs with use of MODIS is limited with regard to the Sichuan region.
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Yu, Zining, Katsumi Hattori, Kaiguang Zhu, Mengxuan Fan, Dedalo Marchetti, Xiaodan He, and Chengquan Chi. "Evaluation of Pre-Earthquake Anomalies of Borehole Strain Network by Using Receiver Operating Characteristic Curve." Remote Sensing 13, no. 3 (February 1, 2021): 515. http://dx.doi.org/10.3390/rs13030515.
Повний текст джерелаАнотація:
In order to monitor temporal and spatial crustal activities associated with earthquakes, ground- and satellite-based monitoring systems have been installed in China since the 1990s. In recent years, the correlation between monitoring strain anomalies and local major earthquakes has been verified. In this study, we further evaluate the possibility of strain anomalies containing earthquake precursors by using Receiver Operating Characteristic (ROC) prediction. First, strain network anomalies were extracted in the borehole strain data recorded in Western China during 2010–2017. Then, we proposed a new prediction strategy characterized by the number of network anomalies in an anomaly window, Nano, and the length of alarm window, Talm. We assumed that clusters of network anomalies indicate a probability increase of an impending earthquake, and consequently, the alarm window would be the duration during which a possible earthquake would occur. The Area Under the ROC Curve (AUC) between true predicted rate, tpr, and false alarm rate, fpr, is measured to evaluate the efficiency of the prediction strategies. We found that the optimal strategy of short-term forecasts was established by setting the number of anomalies greater than 7 within 14 days and the alarm window at one day. The results further show the prediction strategy performs significantly better when there are frequent enhanced network anomalies prior to the larger earthquakes surrounding the strain network region. The ROC detection indicates that strain data possibly contain the precursory information associated with major earthquakes and highlights the potential for short-term earthquake forecasting.
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Sriram, Aditya, Shahryar Rahanamayan, and Farid Bourennani. "Artificial Neural Networks for Earthquake Anomaly Detection." Journal of Advanced Computational Intelligence and Intelligent Informatics 18, no. 5 (September 20, 2014): 701–13. http://dx.doi.org/10.20965/jaciii.2014.p0701.
Повний текст джерелаАнотація:
Earthquakes are natural disasters caused by an unexpected release of seismic energy from extreme levels of stress within the earth’s crust. Over the years, earthquake prediction has been a controversial research subject that has challenged even the smartest ofminds. Because numerous seismic precursors and other factors exist that may indicate the potential of an earthquake occurring, it is extremely difficult to predict the exact time, location, and magnitude of an impending quake. Nevertheless, evaluating a combination of these precursors through advances in Artificial Intelligence (AI) can certainly increase the possibility of predicting an earthquake. The sole purpose for predicting a seismic event at a pre-determined locality is to provide substantial time for the citizens to take precautionary measures. With this in mind, Artificial Neural Networks (ANNs) have been promising techniques for the detection and prediction of locally impending earthquakes based on valid seismic information. To highlight the recent trends in earthquake abnormality detection, including various ideas and applications, in the field of Neural Networks, valid papers related to ANNs are reviewed and presented herein.
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Biagi, P. F., R. Piccolo, A. Ermini, Y. Fujinawa, S. P. Kingsley, Y. M. Khatkevich, and E. I. Gordeev. "Hydrogeochemical precursors of strong earthquakes in Kamchatka: further analysis." Natural Hazards and Earth System Sciences 1, no. 1/2 (June 30, 2001): 9–14. http://dx.doi.org/10.5194/nhess-1-9-2001.
Повний текст джерелаАнотація:
Abstract. For many years, ion and gas content data have been collected from the groundwater of three deep wells in the southern area of the Kamchatka peninsula, Russia. In the last ten years, five earthquakes with M > 6.5 have occurred within 250 km of the wells. In a previous study, we investigated the possibility that the hydrogeochemical time series contained precursors. The technique used was to assume that each signal with an amplitude of three times the standard deviation is an irregularity and we then defined anomalies as irregularities occurring simultaneously in the data for more than one parameter at each well. Using this method, we identified 11 anomalies with 8 of them being possible successes and 3 being failures as earthquake precursors. Precursors were obtained for all five earthquakes that we considered. In this paper, we allow for the cross-correlation found between the gas data sets and in some cases, between the ion data sets. No cross-correlation has been found between gas and ion content data. Any correlation undermines the idea that an anomaly might be identified from irregularities appearing simultaneously on different parameters at each site. To refine the technique, we re-examine the hydrogeochemical data and define as anomalies those irregularities occurring simultaneously only in the data of two or more uncorrelated parameters. We then restricted the analysis to the cases of just the gas content data and the ion content data. In the first case, we found 6 successes and 2 failures, and in the second case, we found only 3 successes. In the first case, the precursors appear only for three of the five earthquakes we considered, and in the second case, only for two, but these are the earthquakes nearest to the wells. Interestingly, it shows that when a strict set of rules for defining an anomaly is used, the method produces only successes and when less restrictive rules are used, earthquakes further from the well are implicated, but at the cost of false alarms being introduced.
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Chiarabba, C., P. De Gori, M. Segou, and M. Cattaneo. "Seismic velocity precursors to the 2016 Mw 6.5 Norcia (Italy) earthquake." Geology 48, no. 9 (June 1, 2020): 924–28. http://dx.doi.org/10.1130/g47048.1.
Повний текст джерелаАнотація:
Abstract Earthquakes occur as the result of long-term strain accumulation on active faults and complex transient triggering mechanisms. Although laboratory experiments show accelerating deformation patterns before failure conditions are met, imaging similar preparatory phases in nature remains difficult because it requires dense monitoring in advance. The 2016 Amatrice-Visso-Norcia (central Italy) earthquake cascade, captured by an unprecedented seismic network, provided a unique testing ground to image the preparatory phase of a large event. The crustal volume of the Norcia incipient fault was densely illuminated by seismic rays from more than 13,000 earthquakes that occurred within the 3 mo before the main shock nucleation. We performed seismic tomography in distinct time windows that revealed the precursory changes of elastic wave speed, signaling (1) the final locked state of the fault, and (2) the rapid fault-stiffness alterations near the hypocenter just a few weeks before the event. The results are the first instance where short-lived, hard-to-catch crustal properties shed light on evolving earthquake cascades.
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Riga, Giulio, and Paolo Balocchi. "Double Earthquakes Classification and Seismic Precursors." Open Journal of Earthquake Research 07, no. 01 (2018): 1–27. http://dx.doi.org/10.4236/ojer.2018.71001.
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Dovbnya, B. V., A. Yu Pashinin, and R. A. Rakhmatulin. "Short-term electromagnetic precursors of earthquakes." Geodynamics & Tectonophysics 10, no. 3 (September 15, 2019): 731–40. http://dx.doi.org/10.5800/gt-2019-10-3-0438.
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Dolgikh, G. I., A. V. Kuptsov, I. A. Larionov, Yu V. Marapulets, V. A. Shvets, B. M. Shevtsov, O. P. Shirokov, V. A. Chupin, and S. V. Yakovenko. "Deformation and acoustic precursors of earthquakes." Doklady Earth Sciences 413, no. 1 (March 2007): 281–85. http://dx.doi.org/10.1134/s1028334x07020341.
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