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Academic literature on the topic 'Earthquakes precursors'

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Published: 14 March 2023

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Journal articles on the topic "Earthquakes precursors"

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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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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.

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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.
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Dissertations / Theses on the topic "Earthquakes precursors"

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Lopes, da Silva Valencio Arthur. "An information-theoretical approach to identify seismic precursors and earthquake-causing variables." Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=237105.

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Several seismic precursors and earthquake-causing variables have been proposed in the last decades based on physical considerations and case observations, however none has been confirmed on long datasets using linear analysis. This work adopts an information-theoretical approach to investigate the occurrence of causal flow between these precursors and causing variables and seismicity. It starts by introducing the key concepts in seismology and presenting the current main precursor candidates. Four variables will be considered as possible precursors or anomalies leading to earthquakes: large tidal amplitudes, temporal fluctuations in the Gutenberg-Richter's b-value, surface gravity changes, and preceding anomalous seismicity patterns. To perform the causality test between these variables and their effects, it is developed a method which allows the fast calculation of Transfer Entropy for any two time-series, detecting the direction of the flow of information between the variables of interest. The method is tested to coupled logistic maps and networks with different topologies before application to geophysical events. The analysis shows mutual information relating to coupling strength and also allows inference of the causal direction from data using the Transfer Entropy, both in bivariate systems and in networks. The method was then applied to the earthquake analysis for an interval of 4018 days on an area comprising the Japan trench. Within a conservative margin of confidence, the results could not at this point confirm any of the four precursor options considered, but future work can clarify initial suggestions regarding tidal amplitudes link to seismicity, and pre-seismic gravity changes and cumulative daily magnitude anomalies. The Matlab/Octavecodes for our method are open-source and available at https://github.com/artvalencio/causality-toolbox We hope the method is able to support the quest for other precursor candidates, and to assist other fields of knowledge.
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Nuannin, Paiboon. "The Potential of b-value Variations as Earthquake Precursors for Small and Large Events." Doctoral thesis, Uppsala universitet, Institutionen för geovetenskaper, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-6885.

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The potential of variations of b-values in the G-R relation, logN=a-bM as earthquake precursors for small events (rockbursts) in Zinkgruvan mine, Sweden and for tectonic (large) earthquakes in the Andaman-Sumatra region were investigated. The temporal frequency-magnitude distribution, b(t), of rockbursts in Zinkgruvan mine was examined using high quality data recorded during the period November 1996 to April 2004 with magnitude ranges from Mw= -2.4 to 2.6. A sliding time-window was applied to compute b-values. The windows contain 50 events and were shifted with steps of 5 events. The results indicated that b-values significantly drop preceding rockbursts of magnitude Mw≥1.6. Temporal and spatial variations of b-values were also examined for tectonic earthquakes, magnitude Mw≥4.1, in the Andaman-Sumatra region. Earthquake data from the ISC, IDC, NEIC and HVRD earthquake catalogs for a period from 01/01/1995 to 12/26/2004 were used for analysis. Spatial variations of b were calculated from circular areas containing 50 events, with nodes on a 0.5° x 0.5° grid. The analysis shows that b(t) estimates using data from different catalogs are comparable and that large earthquakes are preceded by a drop in b(t) of about 0.3~1. The distribution of stress deduced from b-value mapping shows that large earthquakes occurred in the high stress, i.e. low b-value, areas. Aftershock sequences of the Mw=9, December 26, 2004 and the Mw=8.7, March 28, 2005 shocks were investigated by using the same methods. Results from aftershock sequences show similar behaviour as for the large and presumed independent main events. The observed variations of b-values with time and in space support the hypothesis that b-values have a precursory potential. The method can be used for a wide range of earthquake magnitude, from microearthquakes (Mw<3) to giant tectonic shocks (Mw~9) and for both of independent shocks and aftershocks.
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Eisenbeis, Julian. "Ionospheric Dynamics by GNSS total electron content observations : the effect of Solar Eclipses and the mystery of Earthquake precursors." Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7027.

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Cette thèse porte principalement sur deux sujets: l'un est la signature ionosphérique des éclipses solaires, l'autre est le débat ‘Hole vs Enhancement’. Le 21 août 2017, l'ombre d'une éclipse totale a changé radicalement l'état de l'ionosphère au-dessus des Etats-Unis. Cet effet est visible dans le contenu total en électrons (TEC) mesuré par ~3000 stations GNSS qui voient des multiples satellites GPS et GLONASS. Ce formidable ensemble de données permet une caractérisation à haute résolution du contenu en fréquences et des longueurs d'onde - en utilisant une analyse omega-k basée sur la Transformée de Fourier Rapide (FFT) 3D - de la signature de l'éclipse dans l'ionosphère afin d'identifier complètement les perturbations ionosphériques mobiles (TID). Nous confirmons la génération de TIDs associées à l'éclipse, y compris les TIDs interprétées comme des ondes de proue dans les études précédentes. De plus, nous révélons, pour la première fois, des TID de courte (50-100 km) et de longue (500-600 km) longueurs d'onde avec des périodes entre 30 et 65 min (Eisenbeis et al., 2019). Le 2 juillet 2019, une autre éclipse solaire totale s'est produite à travers le continent sud-américain. Bien que nous n'ayons que des données provenant de plus de cent stations GNSS et situées dans une zone proche du coucher du soleil, nous pouvons montrer la preuve évidente de la signature ionosphérique de l'éclipse (Eisenbeis & Occhipinti in prep.a). Le deuxième grand sujet de ce travail est le débat sur la possibilité de précurseurs de séismes. Heki (2011) a suscité ce débat en publiant les résultats du séisme de Tohoku montrant une amélioration de la TEC avant le séisme. L'amélioration revendiquée par Heki (2011) a été interprétée comme une diminution de la TEC après l'événement, le soi-disant trou ionosphérique dans la littérature. L'existence de l'amélioration a été promue par plusieurs articles (e.g. He & Heki, 2017) étendant l'observation à plusieurs événements de magnitude modérée (M> 7.5) et propose une nouvelle vision de la dynamique de rupture. En essayant de reproduire leurs résultats, nous montrons que la courbe de référence utilisée par Heki (2011) est affectée par l'ordre d'ajustement polynomial ainsi que par les fenêtres temporelles sélectionnées. Ceci montre que l'amélioration du TEC pourrait en fait n'être qu'un artefact, subjectivement sélectionné pour créer le précurseur présumé (Eisenbeis & Occhipinti in prep.b)
This thesis focuses mainly on two topics: one is the ionospheric signature of solar eclipses, the second is the Hole vs Enhancement debate about earthquake precursors. On the 21st August 2017 the shadow of a total eclipse drastically changed the state of the ionosphere over the USA. This effect is visible in the total electron content (TEC) measured by ~3000 GNSS stations seeing multiple GPS and GLONASS satellites. This tremendous dataset allows high-resolution characterization of the frequency content and wavelengths -using an omega-k analysis based on 3D Fast-Fourier-Transform (FFT)- of the eclipse signature in the ionosphere in order to fully identify traveling ionospheric disturbances (TIDs). We confirm the generation of TIDs associated with the eclipse including TIDs interpreted as bow waves in previous studies. Additionally we reveal, for the first time, short (50-100 km) and long (500-600 km) wavelength TIDs with periods between 30 and 65 min (Eisenbeis et al., 2019). On 2nd July 2019 another total solar eclipse happened across the South American continent at magnetic conjugate latitudes as the Great American Eclipse, and consequently useful to visualize the difference response. Although for the South American eclipse we have only data from more than hundred GNSS stations and located in a zone close to the sunset, we can show the clear evidence of the ionospheric signature of the eclipse (Eisenbeis & Occhipinti in prep.a).The second major topic in this work is the still ongoing debate about the possibility of earthquake precursors. Heki (2011) sparked this debate when he published results of the Tohoku earthquake showing a TEC enhancement before the earthquake. The enhancement claimed by Heki (2011) has been interpreted as a decrease in the background TEC after the seismic event, the so called ionospheric hole in literature. The existence of the enhancement has been promoted by several papers (e.g. He & Heki, 2017) extending the observation to several events with moderate magnitude (M> 7.5) and proposes a new vision of the rupture dynamics. By trying to reproduce their results we show that the reference curve used by Heki (2011) to define the TEC background is strongly affected by the order of polynomial fit as well as the selected time windows. This shows that the TEC enhancement could be, in fact, just an artifact, subjectively selected to create the presumed precursor (Eisenbeis & Occhipinti in prep.b)
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Lam, Huu Quang. "DEVELOPMENT OF HAZARD ASSESSMENT TECHNOLOGY OF THE PRECURSOR STAGE OF LANDSLIDES." Kyoto University, 2018. http://hdl.handle.net/2433/232065.

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Adamaki, Angeliki. "Seismicity Analyses Using Dense Network Data : Catalogue Statistics and Possible Foreshocks Investigated Using Empirical and Synthetic Data." Doctoral thesis, Uppsala universitet, Geofysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-328057.

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Precursors related to seismicity patterns are probably the most promising phenomena for short-term earthquake forecasting, although it remains unclear if such forecasting is possible. Foreshock activity has often been recorded but its possible use as indicator of coming larger events is still debated due to the limited number of unambiguously observed foreshocks. Seismicity data which is inadequate in volume or character might be one of the reasons foreshocks cannot easily be identified. One method used to investigate the possible presence of generic seismicity behavior preceding larger events is the aggregation of seismicity series. Sequences preceding mainshocks chosen from empirical data are superimposed, revealing an increasing average seismicity rate prior to the mainshocks. Such an increase could result from the tendency of seismicity to cluster in space and time, thus the observed patterns could be of limited predictive value. Randomized tests using the empirical catalogues imply that the observed increasing rate is statistically significant compared to an increase due to simple clustering, indicating the existence of genuine foreshocks, somehow mechanically related to their mainshocks. If network sensitivity increases, the identification of foreshocks as such may improve. The possibility of improved identification of foreshock sequences is tested using synthetic data, produced with specific assumptions about the earthquake process. Complications related to background activity and aftershock production are investigated numerically, in generalized cases and in data-based scenarios. Catalogues including smaller, and thereby more, earthquakes can probably contribute to better understanding the earthquake processes and to the future of earthquake forecasting. An important aspect in such seismicity studies is the correct estimation of the empirical catalogue properties, including the magnitude of completeness (Mc) and the b-value. The potential influence of errors in the reported magnitudes in an earthquake catalogue on the estimation of Mc and b-value is investigated using synthetic magnitude catalogues, contaminated with Gaussian error. The effectiveness of different algorithms for Mc and b-value estimation are discussed. The sample size and the error level seem to affect the estimation of b-value, with implications for the reliability of the assessment of the future rate of large events and thus of seismic hazard.
Οι προσεισμοί αποτελούν τα πλέον υποσχόμενα πρόδρομα φαινόμενα για τη βραχυπρόθεσμη πρόγνωση των σεισμών, παρόλο που παραμένει άγνωστο το αν μια τέτοια πρόγνωση είναι εφικτή. Η χρήση της προσεισμικής δραστηριότητας ως ένδειξη ενός επερχόμενου μεγάλου σεισμού είναι αμφιλεγόμενη, κυρίως λόγω του περιορισμένου πλήθους των προσεισμών, γεγονός που πιθανά οφείλεται στην ανεπαρκή καταγραφή σεισμικών δεδομένων. Η άθροιση σεισμικών σειρών είναι μια μέθοδος που εφαρμόζεται προκειμένου να μελετηθεί η πιθανή παρουσία ενός γενικευμένου μοτίβου σεισμικότητας πριν από ισχυρούς σεισμούς. Η υπέρθεση σεισμικών ακολουθιών που προηγήθηκαν των κυρίων σεισμών αναδεικνύει μια αυξανόμενη μέση δραστηριότητα πριν από τους κύριους σεισμούς. Μια τέτοια συμπεριφορά θα μπορούσε να προκύψει και από την εγγενή τάση των σεισμών να ομαδοποιούνται χωρικά και χρονικά, με αποτέλεσμα τα παρατηρούμενα μοτίβα να έχουν περιορισμένη προγνωστική αξία. Τυχαιοποιημένοι έλεγχοι των πραγματικών δεδομένων υποδηλώνουν ότι ο παρατηρούμενος αυξανόμενος ρυθμός είναι στατιστικά σημαντικός σε σύγκριση με τη μεταβολή που οφείλεται στη γένεση απλών συστάδων σεισμών, αναδεικνύοντας την ύπαρξη προσεισμών αιτιολογικά συσχετιζόμενων με τους κύριους σεισμούς. Μια ενδεχόμενη αύξηση της ευαισθησίας των σεισμικών δικτύων πιθανά να συμβάλει στην αποτελεσματικότερη αναγνώριση των προσεισμών. Η πιθανότητα μιας τέτοιας βελτίωσης ελέγχεται με τη χρήση συνθετικών δεδομένων τα οποία προκύπτουν υπό προϋποθέσεις ως προς τη σεισμική διαδικασία. Οι επιπλοκές που μπορεί να προκύψουν από την παρουσία σεισμικότητας υποβάθρου και των μετασεισμικών ακολουθιών διερευνώνται αριθμητικά, με γενικευμένες περιπτώσεις και σενάρια που βασίζονται σε πραγματικά δεδομένα. Οι κατάλογοι που περιλαμβάνουν μικρότερους και επομένως περισσότερους σεισμούς μπορούν πιθανώς να συμβάλουν στην καλύτερη κατανόηση των σεισμικών διεργασιών και στη μελλοντική πρόγνωση των σεισμών. Σημαντική πτυχή σε τέτοιες μελέτες αποτελεί η σωστή εκτίμηση των ιδιοτήτων των σεισμικών καταλόγων, όπως είναι το μέγεθος πληρότητας και η παράμετρος b. Η επίδραση των σφαλμάτων των μεγεθών που υπάρχουν στους σεισμικούς καταλόγους στην εκτίμηση των προαναφερθέντων ιδιοτήτων ερευνάται χρησιμοποιώντας συνθετικά μεγέθη στα οποία ενυπάρχουν κανονικώς κατανεμημένα σφάλματα. Κατά τη διερεύνηση της αποτελεσματικότητας των διαφόρων μεθόδων που χρησιμοποιούνται για την εκτίμηση του μεγέθους πληρότητας προκύπτει ότι το μέγεθος του δείγματος και του σφάλματος των μεγεθών μπορούν να επηρεάσουν την εκτίμηση της παραμέτρου b, με επιπτώσεις στην εκτίμηση του ρυθμού των μελλοντικών ισχυρών σεισμών και την αξιολόγηση του σεισμικού κινδύνου.
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Charlie and 陳仕恩. "Using the seismicity,to research into the precursors of great earthquakes." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/22571046485519695349.

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Chun-YuLin and 林純玉. "Application of groundwater radon precursors for recurrent dominant earthquakes near Antung, Taiwan." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/82740027208792384494.

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Yu-HsuanTu and 杜宇軒. "Analyzing Earthquake Precursors with High-rate GPS Signal." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/71477515572067134500.

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Abstract:
碩士
國立成功大學
資源工程學系碩博士班
98
There is evidence shows large earthquakes will release ultra-low frequency electromagnetic wave to the surface and thus disturb the concentration of ion within atmosphere recently. With the development of global navigation satellite system (GNSS) technology, applications of using high-rate GPS signal in atmospheric perturbation detecting and coseismic displacement measuring are also increased. In this study, 20 Hz GPS data was used to observe the signal variations of ionosphere concentration prior to 14 days of Kaohsiung Jiaxian earthquake (ML 6.4), March 4th, 2010, to analyze the possible abnormal signs. GPS displacement data with kinematic filter technique is used to compare with seismograph data. Results showed that three days before the earthquake ruptured a lower value of total electron content (TEC) in low-data-resolution carrier phase variations have found. After the data resolution is enhanced, there is no significant change under such circumstances due to the increasing of signal to noise ratio. After extracting the high-frequency signals, we found that there is no significant change prior to the earthquake. On the other hand, the GPS filtered displacement signal and signal of seismograph are highly similar except the GPS has more noise in very low frequency part (＜ 0.002 Hz). The measurements of data from main frequency of earthquake are very similar to each other within this study, which proved the feasibility of using high-rate GPS for strong motion displacement measurement, and provides the true ground motion without interference from the instrument response of seismograph.
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Sulçe, Ardit. "Is land surface temperature an earthquake precursor?" Master's thesis, 2013. http://hdl.handle.net/10362/9188.

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Dissertation submitted in partial fulfillment of the requirements for the Degree of Master of Science in Geospatial Technologies
This study aims to investigate and explain the land surface temperature variations before and after the earthquake of August 11, 2012 that struck Iran, by making critical considerations of weather factors. This goal underlies two main objectives. The first objective was to detect land surface temperature anomalies over time in respect to the day of the earthquake, and over space relative to the location of the earthquake epicentre. The other main objective was to determine whether the detected anomalies originated from the weather, or the earthquake. To meet these objectives, observations of remote sensing land surface temperature, near-ground air temperature and air temperature of multiple atmospheric levels were used. All the datasets were daily night-time observations extending to a period of five years, repeatedly from July 11, to August 31. All the observations of the three datasets were visualized in space and time to seek anomalous temperature patterns. The results showed several prominent land surface temperature increases over the 5-year period, but none of them fell out a few days before the earthquake. The most enduring land surface temperature increase occurred two days after the earthquake. In contrast to the land surface temperature, air temperature exhibited the sharpest anomalies of the entire period a few days before the earthquake. Both the air and the land surface temperature increased periodically few times within the 5-year period. The high temperature patterns that were detected in the near-ground air also matched in time with the patterns found in the temperature of multiple atmospheric levels. All three approaches undertaken in this study were consistent with each-other in terms of results. Based on those results, it was concluded that there were no land surface temperature anomalies in the expected few days before the earthquake. All the detected temperature increases were indeed seasonal patterns repeating roughly in the same period of the year, and in the same spatial extent and intensity. These warm patterns were due to normal weather cycles. The sharp air temperature anomalies detected in the few days preceding the earthquake may suggest that the focus, if thermal precursors exist at all, should indeed be set on the air temperature instead of land surface temperature.
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Yi-HueiHsu and 許逸惠. "Monitoring Groundwater Radon for Earthquake Precursors near Antung, Taiwan." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/64645503435054869167.

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Abstract:
碩士
國立成功大學
資源工程學系碩博士班
101
We monitored groundwater-dissolved radon at both well D1 and well A in the Antung hot spring to catch earthquake precursors. Prior to the 2011 MW 5.0 Chimei earthquake, the groundwater’s radon concentration at well D1 decreased from a background level of 752 ± 24 pCi/L to a minimum of 447 ± 18 pCi/L. No precursory changes in the groundwater’s radon concentration were observed at well A precursory to the 2011 MW 5.0 Chimei earthquake. Recurrent anomalous declines in groundwater radon were observed at the Antung D1 monitoring well prior to the four major earthquakes – (1) 2003 MW = 6.8 Chengkung, (2) 2006 MW = 6.1 Taitung, (3) 2008 MW = 5.4 Antung, and (4) 2011 MW = 5.4 Chimei. Post the 2011 Chimei earthquake, additional recurrent anomalous declines in groundwater radon were observed at well D1 prior to four local earthquakes with ML ≥ 4.7. For earthquakes occurring on the Longitudinal Valley Fault in eastern Taiwan, the observed radon minima decrease as the earthquake magnitude increases.
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Books on the topic "Earthquakes precursors"

1

Pulinets, S. Ionospheric precursors of earthquakes. Berlin: Springer, 2004.

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Kirill, Boyarchuk, ed. Ionospheric precursors of earthquakes. Berlin: Springer, 2004.

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F, Biagi P., Kingsley Simon 1949-, Vallianatos F, and European Geophysical Society. General Assembly, eds. Earthquake precursors. Oxford, England: Pergamon, 2000.

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Takeshi, Mikumo, ed. Earthquake source physics and earthquake precursors. Amsterdam: Elsevier, 1992.

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Wyss, Max, ed. Evaluation of Proposed Earthquake Precursors. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032.

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Pulinets, Sergey, Dimitar Ouzounov, Alexander Karelin, and Kyrill Boyarchuk. Earthquake Precursors in the Atmosphere and Ionosphere. Dordrecht: Springer Netherlands, 2022. http://dx.doi.org/10.1007/978-94-024-2172-9.

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Caputo, Michele. Sismologia e segnali precursori dei terremoti. Bologna: Calderini, 1987.

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Michael, A. J. The evaluation of VLF guided waves as possible earthquake precursors. [Reston, Va.?]: Dept. of the Interior, U.S. Geological Survey, 1996.

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J, Budnitz R., U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Systems Technology., and Future Resources Associates Inc, eds. A Methodology for analyzing precursors to earthquake-initiated and fire-initiated accident sequenes. Washington, DC: Division of Systems Technology, Office of Nuclear Regulatory Commission, 1998.

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J, Budnitz R., U.S. Nuclear Regulatory Commission. Office of Nuclear Regulatory Research. Division of Systems Technology., and Future Resources Associates Inc, eds. A Methodology for analyzing precursors to earthquake-initiated and fire-initiated accident sequenes. Washington, DC: Division of Systems Technology, Office of Nuclear Regulatory Commission, 1998.

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Book chapters on the topic "Earthquakes precursors"

1

Wang, Chi-Yuen, and Michael Manga. "Hydrologic Precursors." In Lecture Notes in Earth System Sciences, 343–68. Cham: Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-64308-9_13.

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AbstractPredicting earthquakes is a long-desired goal. The main challenge is to identify precursory signals that reliably predict the impending earthquake. Since hydrological and hydrogeochemical properties and processes can be very sensitive to minute strains, the hope is that measurements from hydrological systems might record precursory rock deformation that would otherwise be undetectable. Of the many hundreds of studies, we review a subset to illustrate how signals can be challenging to interpret and highlight questions raised by observations—examples come from China, Japan, Taiwan, India, the USA, Russia, France, Italy and Iceland. All are retrospective studies. Some signals seem to have no other explanation than being precursory, however, rarely is enough data available to undertake a thorough analysis. Some hydrological precursors might be recording deformation events that are slower than traditional earthquakes (and hence usually harder to detect). Long times series of data are critical for both identifying putative precursors and assessing their origin and reliability.
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Wang, Chi-Yuen, and Michael Manga. "Hydrologic Precursors." In Earthquakes and Water, 141–59. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-642-00810-8_9.

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Wyss, Max. "Precursors to Large Earthquakes." In Practical Approaches to Earthquake Prediction and Warning, 519–43. Dordrecht: Springer Netherlands, 1985. http://dx.doi.org/10.1007/978-94-017-2738-9_18.

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Qingguo, Geng. "Case 20: Drought-earthquake relation and medium-range prediction of great earthquakes." In Evaluation of Proposed Earthquake Precursors, 93–94. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0093.

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Gupta, H. K., and H. N. Singh. "Case 10: Medium term earthquake prediction and earthquake swarms precursory to moderate magnitude to great earthquakes." In Evaluation of Proposed Earthquake Precursors, 64–67. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0064.

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Martinelli, Giovanni, and Andrea Dadomo. "Geochemical and Fluid-Related Precursors of Earthquakes." In Pre-Earthquake Processes, 219–28. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2018. http://dx.doi.org/10.1002/9781119156949.ch12.

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Oike, K., and T. Ogawa. "Case 14: Electromagnetic radiations from shallow earthquakes observed in the LF range." In Evaluation of Proposed Earthquake Precursors, 77. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0077.

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Duan, H. C. "Case 19: Deformation precursors in the mid-term stage at the area near the epicenter of strong earthquakes." In Evaluation of Proposed Earthquake Precursors, 91–92. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0091.

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Sato, H. "Case 16: Precursory changes before the Nankai earthquake of 1946, In some precursors prior to recent great earthquakes along the Nankai trough." In Evaluation of Proposed Earthquake Precursors, 84–85. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0084.

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Zhang, C., J. Y. Guo, X. S. Xie, and L. W. Chen. "Case 18: Theoretical modeling on characteristics of fault creep and its propagation along the Xianshuine fault in the interval between two strong earthquakes." In Evaluation of Proposed Earthquake Precursors, 88–90. Washington, D. C.: American Geophysical Union, 1991. http://dx.doi.org/10.1029/sp032p0088.

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Conference papers on the topic "Earthquakes precursors"

1

Kashkin, Valentine B., Roman V. Odintsov, Konstantin V. Simonov, Tatyana V. Rubleva, and Aleksey A. Kabanov. "Atmospheric precursors to Baikal earthquakes." In 27th International Symposium on Atmospheric and Ocean Optics, Atmospheric Physics, edited by Oleg A. Romanovskii and Gennadii G. Matvienko. SPIE, 2021. http://dx.doi.org/10.1117/12.2603444.

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Pyankov, V. A., and A. L. Rublev. "The new paradigm of earthquakes radon precursors." In 18th International Conference on Geoinformatics - Theoretical and Applied Aspects. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201902144.

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Biagi, Pier Francesco, Cataldo Guaragnella, Andrea Guerriero, Ciriaco Ciro Pasquale, and Francesco Ragni. "A Data Warehouse for earthquakes signal precursors analysis." In 2009 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS). IEEE, 2009. http://dx.doi.org/10.1109/eesms.2009.5341316.

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Zoran, Maria A., Roxana S. Savastru, Dan M. Savastru, and Doru N. Mateciuc. "Geospatial and field survey data for earthquakes multi-precursors detection." In Earth Resources and Environmental Remote Sensing/GIS Applications X, edited by Karsten Schulz, Konstantinos G. Nikolakopoulos, and Ulrich Michel. SPIE, 2019. http://dx.doi.org/10.1117/12.2532886.

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Zoran, Maria A., Roxana S. Savastru, and Dan M. Savastru. "Multi-precursors assessment of earthquakes by geospatial and ground data." In Sixth International Conference on Remote Sensing and Geoinformation of the Environment (RSCy2018), edited by Kyriacos Themistocleous, Diofantos G. Hadjimitsis, Silas Michaelides, Vincent Ambrosia, and Giorgos Papadavid. SPIE, 2018. http://dx.doi.org/10.1117/12.2324958.

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Herepanova, E. "SATELLITE MONITORING OF SEISMIC ZONES BASED ON EARTHQUAKES PRECURSORS ANALYSIS: CENTRAL ITALY EARTHQUAKE AUGUST 2016 CASE STUDY." In 18th International Multidisciplinary Scientific GeoConference SGEM2018. Stef92 Technology, 2018. http://dx.doi.org/10.5593/sgem2018/2.2/s08.049.

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Tramutoli, V., S. Inan, N. Jakowski, S. Pulinets, Alexey Romanov, C. Filizzola, I. Shagimuratov, et al. "PRE-EARTHQUAKES, an FP7 project for integrating observations and knowledges on earthquake precursors: Preliminary results and strategy." In IGARSS 2012 - 2012 IEEE International Geoscience and Remote Sensing Symposium. IEEE, 2012. http://dx.doi.org/10.1109/igarss.2012.6350656.

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Kozyrev, Anatolii. "PRECURSORS OF MINING-INDUCED EARTHQUAKES: ANALYSIS OF CHANGES IN ROCK MASS SEISMICITY." In 15th International Multidisciplinary Scientific GeoConference SGEM2015. Stef92 Technology, 2011. http://dx.doi.org/10.5593/sgem2015/b12/s2.076.

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Sasmal, Sudipta, Sandip K. Chakrabarti, and Suman Ray. "Studies of precursors of earthquakes using anomalies in very low frequency signal." In 2014 XXXIth URSI General Assembly and Scientific Symposium (URSI GASS). IEEE, 2014. http://dx.doi.org/10.1109/ursigass.2014.6929820.

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Carducci, Leonardo M., Ramiro Alonso, and Walter G. Fano. "Data acquisition system for the study of earthquakes precursors by measuring magnetic field emissions." In 2017 XVII Workshop on Information Processing and Control (RPIC). IEEE, 2017. http://dx.doi.org/10.23919/rpic.2017.8214332.

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Reports on the topic "Earthquakes precursors"

1

Korneev, Valeri A. Seismicity Precursors of the M6.0 2004 Parkfield and M7.0 1989Loma Prieta Earthquakes. Office of Scientific and Technical Information (OSTI), March 2006. http://dx.doi.org/10.2172/901226.

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Korneev, Valeri. Acoustic Emission Precursors of M6.0 2004 Parkfield and M7.0 1989Loma Prieta Earthquakes. Office of Scientific and Technical Information (OSTI), February 2005. http://dx.doi.org/10.2172/929749.

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Farahbod, A. M., and J. F. Cassidy. Temporal variations in coda Q before and after the 2017 Barrow Strait earthquake (Mw 5.9) in Nunavut and the 2012 Haida Gwaii earthquake (Mw 7.8) in British Columbia. Natural Resources Canada/CMSS/Information Management, 2022. http://dx.doi.org/10.4095/331095.

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In this study, we examine potential temporal changes in coda Q values for two significant Canadian earthquakes in different tectonic environments: the 2017 (Mw 5.9) Barrow Strait earthquake along Canada's northern margin and the 2012 (Mw 7.8) Haida Gwaii subduction earthquake on Canada's west coast. Waveforms from 124 earthquakes (2.0 &amp;lt;/= M &amp;lt;/= 4.6) for ~30 years prior to the January 8, 2017 Barrow Strait earthquake and 66 events (mainly aftershocks of M 2.0-5.3) in about 4 years after the mainshock recorded by the closest seismic station (RES) of the Canadian National Seismograph Network (CNSN) were utilized in this study. Based on our analysis, overall average of Q0 (Q at 1 Hz) decreased from 92 (before the mainshock) to 81. The most significant decrease in the frequency range between 2 and 16 Hz is observed for areas corresponding to ellipse parameter a2 of 50, 70 and 80 mainly related to aftershock activity. Precursory Q changes could not be evaluated before the mainshock due to the lack of reported seismicity within 100 km of the recording seismic station for almost 2 years from April 2015 to January 2017. Coda Q values before and after the October 28, 2012 Haida Gwaii earthquake in British Columbia show a similar pattern. Waveforms from 249 earthquakes (2.0 &amp;lt;/= M &amp;lt;/= 4.9) in 2 years before the mainshock and 498 events (2.5 &amp;lt;/= M &amp;lt;/= 6.3) in 2 years after the mainshock recorded by the three closest seismic stations of the CNSN were utilized. Overall average of Q0 decreased from 89 (before the mainshock) to 69 (station BNB), from 90 to 79 (station DIB) and from 86 to 78 (station VIB). In general, these results are in agreement with other global studies that show a decrease in Q0 following a major earthquake, likely the result of increased fracturing and fluids in the epicentral region.
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Adams, J. A precursory sub-event to the Mont-Laurier earthquake. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 1995. http://dx.doi.org/10.4095/315315.

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Budnitz, R. J., H. E. Lambert, and G. Apostolakis. A methodology for analyzing precursors to earthquake-initiated and fire-initiated accident sequences. Office of Scientific and Technical Information (OSTI), April 1998. http://dx.doi.org/10.2172/595605.

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