scholarly journals Estimation of parameters (date and magnitude) of two strong earthquakes in Iran by integrating different earthquake precursors

2021 ◽  
Vol 9 (2) ◽  
pp. 67-81
Author(s):  
Mohammad Mahdi Khoshgoftar ◽  
Mohammad Reza Saradjian ◽  
◽  
Keyword(s):  
Earthquake Precursors ◽  
Estimation Of Parameters ◽  
Strong Earthquakes

scholarly journals PHASE REARRANGEMENT IN LOCAL BALANCED HYDROGEOCHEMICAL SYSTEMS AS A OF FLUID EARTHQUAKE PRECURSORS MECHANISM OCCURRENCE

2019 ◽  
Vol 16 (33) ◽  
pp. 248-258
Author(s):  
A. U. ABDULLAEV
Keyword(s):  
Earthquake Prediction ◽  
Structural Relaxation ◽  
Earthquake Precursors ◽  
Strong Earthquakes ◽  
Major Earthquake ◽  
Time Period ◽  
Internal Phase ◽  
The World ◽  
Precursors Of Earthquakes ◽  
Hydrogeochemical System

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.

scholarly journals Prediction of the date, magnitude and affected area of impending strong earthquakes using integration of multi precursors earthquake parameters

2011 ◽  
Vol 11 (4) ◽  
pp. 1109-1119 ◽  
Author(s):  
M. R. Saradjian ◽  
M. Akhoondzadeh
Keyword(s):  
Land Surface ◽  
Earthquake Precursors ◽  
Electron Content ◽  
Total Electron ◽  
Earthquake Parameters ◽  
Strong Earthquakes ◽  
Affected Area ◽  
Inter Quartile Range ◽  
Quartile Range

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.

scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2007 ◽  
Vol 1(6)2007 (1(6)) ◽  
pp. 5-10
Author(s):  
T.V. Guseva ◽  
◽  
L. Latynina ◽  
Keyword(s):  
Earthquake Precursors ◽  
Gps Measurements ◽  
Strong Earthquakes ◽  
The Earth ◽  
Gps Measurement ◽  
Large Frequency ◽  
Crust Surface ◽  
Horizontal Displacements

The important problems of the GPS measurements are the searches of the earthquake precursors and study of irreversible and varying displacement of the Earth crust, due to the strongest earthquakes. With development of GPS systems and improvement of satellite technologies of measurements and methods of processing there was possible to in detail register the processes occurring during activization of seismicity. GPS measurement with the large frequency of registration of satellite signals are the powerful tool of study longperiodical waves at the strongest earthquakes. There are considered the examples of registration of the irreversible and coseismical horizontal displacements and deformations of the Earth crust surface arising during the tectonical processes, accompanied the strong earthquakes (Izmit by 1999, Alaska 2002, Sumatra 2004 etc.).

scholarly journals Identification of ionospheric earthquake precursors in Kamchatka region based on correlation analysis

2021 ◽  
pp. 150-158
Author(s):  
В.В. Богданов ◽  
А.В. Павлов
Keyword(s):  
Statistical Analysis ◽  
Correlation Coefficient ◽  
Critical Frequency ◽  
Earthquake Precursors ◽  
The Other ◽  
Concentration Change ◽  
Strong Earthquakes ◽  
Ionospheric Variability ◽  
Kamchatka Region ◽  
Critical Frequency Fof2

Сейсмическая активность является одним из источников изменчивости ионосферы. В данной работе на основе методики [1] исследовано изменение концентрации электронов в ионосфере, предшествующее наступлению сильных землетрясений с M ≥ 6.0 в Камчатском регионе. Данная методика основана на вычислении коэффициента корреляции между значениями критической частоты foF2 двух ионосферных станций, одна из которых расположена внутри зоны подготовки землетрясения, а другая – за ее пределами. Рассмотрены данные, полученные на двух станциях PETROPAVLOVSK (PK553) и EARECKSON (EA653) за период 01.09.2018–30.04.2021 гг. Статистический анализ критических частот foF2 показал, что для 6 из 8 землетрясений с M ≥ 6.0, произошедших на глубинах до 100 км и эпицентральных расстояниях до 500 км от расположения PK553, за 1–12 суток до их наступления предшествовало заметное уменьшение коэффициента корреляции. Seismic activity is one of the sources of ionospheric variability. In this work, we investigate electron concentration change in the ionosphere, preceding the onset of strong earthquakes with M ≥ 6.0 in Kamchatka region. The research technique is based on calculating the correlation coefficient between the critical frequency foF2 values at two ionospheric stations. One of them is located inside the earthquake preparation zone, and the other is outside it. The data obtained at two stations PETROPAVLOVSK (PK553) and EARECKSON (EA653) for the period 01.09.2018–30.04.2021 are considered. Statistical analysis of the critical frequencies foF2 showed that a noticeable decrease in the correlation coefficient was observed 1–7 days before the earthquakes for 6 out of 8 events with M ≥ 6.0 that occurred at depths of up to 100 km and epicentral distances of up to 500 km from the PK553 location.

Integrated Search for Taiwan Earthquake Precursors (iSTEP)

2016 ◽  
Vol 136 (5) ◽  
pp. 214-220 ◽  
Author(s):  
Jann-Yenq Liu ◽  
Yi-Ben Tsai ◽  
Chieh-Hung Chen ◽  
Yuh-Ing Chen ◽  
Horng-Yuan Yen
Keyword(s):  
Earthquake Precursors ◽  
Taiwan Earthquake
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