scholarly journals Relation between seismicity and pre-earthquake electromagnetic emissions in terms of energy, information and entropy content

2012 ◽  
Vol 12 (4) ◽  
pp. 1179-1183 ◽  
Author(s):  
S. M. Potirakis ◽  
G. Minadakis ◽  
K. Eftaxias
Keyword(s):  
Fisher Information ◽  
Approximate Entropy ◽  
Radar Interferometry ◽  
Fault Segment ◽  
Athens Earthquake ◽  
Electromagnetic Emissions ◽  
Main Fault ◽  
First Time ◽  
Energy Information ◽  
Secondary Fault

Abstract. In this paper we show, in terms of Fisher information and approximate entropy, that the two strong impulsive kHz electromagnetic (EM) bursts recorded prior to the Athens earthquake (EQ) (7 September 1999, magnitude 5.9) present compatibility with the radar interferometry data and the seismic data analysis, which indicates that two fault segments were activated during Athens EQ. The calculated Fisher information and approximate entropy content ratios closely follow the radar interferometry result that the main fault segment was responsible for 80 % of the total energy released, while the secondary fault segment for the remaining 20 %. This experimental finding, which appears for the first time in the literature, further enhances the hypothesis for the seismogenic origin of the analyzed kHz EM bursts.

scholarly journals COMPLEXITY-BASED ANALYSIS OF THE ALTERATIONS IN THE STRUCTURE OF CORONAVIRUSES

Fractals ◽  
2021 ◽  
Vol 29 (02) ◽  
pp. 2150123
Author(s):  
HAMIDREZA NAMAZI ◽  
ALI SELAMAT ◽  
ONDREJ KREJCAR
Keyword(s):  
Hurst Exponent ◽  
Complex Structure ◽  
Approximate Entropy ◽  
Sample Entropy ◽  
Long Term Memory ◽  
Complex Structures ◽  
Term Memory ◽  
The World ◽  
First Time

The coronavirus has influenced the lives of many people since its identification in 1960. In general, there are seven types of coronavirus. Although some types of this virus, including 229E, NL63, OC43, and HKU1, cause mild to moderate illness, SARS-CoV, MERS-CoV, and SARS-CoV-2 have shown to have severer effects on the human body. Specifically, the recent known type of coronavirus, SARS-CoV-2, has affected the lives of many people around the world since late 2019 with the disease named COVID-19. In this paper, for the first time, we investigated the variations among the complex structures of coronaviruses. We employed the fractal dimension, approximate entropy, and sample entropy as the measures of complexity. Based on the obtained results, SARS-CoV-2 has a significantly different complex structure than SARS-CoV and MERS-CoV. To study the high mutation rate of SARS-CoV-2, we also analyzed the long-term memory of genome walks for different coronaviruses using the Hurst exponent. The results demonstrated that the SARS-CoV-2 shows the lowest memory in its genome walk, explaining the errors in copying the sequences along the genome that results in the virus mutation.

scholarly journals Tectonic structure of Central-Western Attica (Greece) based on geophysical in vestigations-Preliminary results

2018 ◽  
Vol 40 (3) ◽  
pp. 1207 ◽  
Author(s):  
T. D. Papadopoulos ◽  
N. Goulty ◽  
N. S. Voulgaris ◽  
J. D. Alexopoulos ◽  
I. Fountoulis ◽  
...  
Keyword(s):  
Geophysical Methods ◽  
Geological Structure ◽  
Fault Zones ◽  
Geophysical Investigation ◽  
Preliminary Results ◽  
Athens Earthquake ◽  
Gravity Measurements ◽  
Geological Sciences ◽  
First Time ◽  
Seismic Lines

In an effort to investigate the deep geological structure in the broader area of central-western Attica, that suffered severe damage during the destructive Athens earthquake of September 7th, 1999, the Department of Geophysics-Geothermics of the Faculty of Geology and Geoenvironment of Athens University, in collaboration with the Geodynamic Institute of National Observatory of Athens and the Department of Geological Sciences of Durham University, carried out a combined geophysical survey. For the first time in Attica, seismic and gravity geophysical methods were applied along profiles, in such an extensive scale. Within the framework of this investigation the following tasL· were accomplished: a) Three (3) seismic lines of about 30 kilometres of total length, two (2) in the area of Thriassion plain and one (1) along the Parnitha-Krioneri-Drosia-Ekali-Dionysos axis (Attica plain) and b) 338 gravity measurements distributed along eight (8) gravity profiles, four (4) of which in Thriassion plain, three (3) in Petroupoli-Aharnes-Thrakomakedones region (Attica plain) and one (1) along Parnitha-Krioneri-Drosia-Ekali-Dionysos axis (Attica plain). Preliminary results of the geophysical investigation combined with existing geological and tectonic data are presented in this paper. Significant variation in the elevation of the alpine basement has been detected, expressed by manifestation of low and high subsurface areas which are well correlated with existing fault zones. In the area of Thriassion plain the thickness of post-alpine sediments is estimated of a few hundred meters (<500 meters) and huge thickness of several hundred meters (-800 meters) of post-alpine sediments were detected in Thrakemakedones and Krioneri areas. The relief of alpine basement is more intense in fault zones areas, such as Thriassion plain (WNW-ESE), Pathitha and Kifissos (NE-SW) as well as along the fault zone outline the Fili and Aharnes graben and is covered by postalpine formations

Fisher information and Shannon entropy calculations for two-electron systems

2020 ◽  
Vol 98 (8) ◽  
pp. 784-789 ◽  
Author(s):  
Ibraheem Nasser ◽  
Afaf Abdel-Hady
Keyword(s):  
Fisher Information ◽  
Yukawa Potential ◽  
Shannon Information ◽  
Electron Systems ◽  
Charge Densities ◽  
Screening Parameter ◽  
Information Products ◽  
Physical Features ◽  
First Time

Fisher information is calculated for the ground state of He-isoelectronic series, in position ([Formula: see text]) space. The results are given and discussed as a function of the nuclear charge (Z) and the screening parameter (λ) in the case study of Yukawa potential. Simple and explicit one-, two-, and three-correlated terms of Hylleraas wave function are used to focus on extracting the most characteristic physical features of the results. The numerical values of Fisher information are given in 1- and 2-electron charge densities, and their ratio of 2- to 1-electron densities results are defined and analyzed. To enable a comparison with others, the Fisher–Shannon information products, which measure the electron–electron correlation strength, are calculated in 1-electron density. The calculations of Fisher information, the ratio, and the Shannon-information products for two-electron systems in the presence of Yukawa potential are carried out for the first time in this study.

Hydrocarbon Accumulation Dominant Factors and Modes of Minghuazhen Formation in Chengdao Area

2014 ◽  
Vol 628 ◽  
pp. 372-375
Author(s):  
Yang Hu ◽  
Zhi Ping Wu ◽  
Guang Zeng Wang
Keyword(s):  
Structural Characteristics ◽  
Tectonic Setting ◽  
Geochemical Data ◽  
Hydrocarbon Accumulation ◽  
Fault Activity ◽  
Sand Body ◽  
Main Target ◽  
Main Fault ◽  
Recognition Level ◽  
Secondary Fault

Chengdao area is a multiple hydrocarbon accumulation belt with the typical tectonic background, and its main target stratum is Neogene. However, the exploration and recognition level of Minghuazhen Formation is still at the primary stage. Based on the comprehensive analysis of seismic, well-logging, logging and geochemical data, and combined with its structural characteristics, intensity of fault activity and reservoir-caprock assemblage, this paper systematically analyzed the dominant factors of hydrocarbon accumulation in Minghuazhen Formation, and clarified that the tectonic setting controlled where the hydrocarbon enriched, intensity of fault activity influenced how much of hydrocarbon enriched and the reservoir-seal assemblage dominated hydrocarbon accumulation strata. Then two types of hydrocarbon accumulation models, that is, main fault-sand body and main fault-secondary fault–sand body were established.

scholarly journals AUTOMATIC DETECTION OF EPILEPSY EEG USING NEURAL NETWORKS

2012 ◽  
pp. 241-245
Author(s):  
SATYANARAYANA VOLLALA ◽  
KARNAKAR GULLA
Keyword(s):  
Neural Networks ◽  
Detection System ◽  
Statistical Parameter ◽  
Approximate Entropy ◽  
Epileptic Activity ◽  
Diagnostic Systems ◽  
Physiological Signal ◽  
Eeg Data ◽  
Eeg Recordings ◽  
First Time

The electroencephalogram (EEG) signal plays an important role in the diagnosis of epilepsy. The EEG recordings of the ambulatory recording systems generate very lengthy data and the detection of the epileptic activity requires a timeconsuming analysis of the entire length of the EEG data by an expert. The traditional methods of analysis being tedious, many automated diagnostic systems for epilepsy has emerged in recent years.This paper proposes a neural-network-based automated epileptic EEG detection system that uses approximate entropy (ApEn) as the input feature. ApEn is a statistical parameter that measures the predictability of the current amplitude values of a physiological signal based on its previous amplitude values. It is known that the value of the ApEn drops sharply during an epileptic seizure and this fact is used in the proposed system.Two different types of neural networks, namely, Elman and probabilistic neural networks are considered. ApEn is used for the first time in the proposed system for the detection of epilepsy using neural networks. It is shown that the overall accuracy values as high as 100% can be achieved by using the proposed system.

scholarly journals Inversion of the Slip Distribution of the 2017 Ms7.0 Jiuzhaigou Earthquake From InSAR

2020 ◽  
Author(s):  
Xiongwei Tang ◽  
Rumeng Guo ◽  
Jianqiao Xu ◽  
Heping Sun ◽  
Xiaodong Chen ◽  
...  
Keyword(s):  
Tectonic Stress ◽  
Fault Model ◽  
Slip Distribution ◽  
Obtuse Angle ◽  
Coseismic Deformation ◽  
Jiuzhaigou Earthquake ◽  
The North ◽  
Finite Fault ◽  
Main Fault ◽  
Secondary Fault

Abstract On 8 August 2017, an Ms 7.0 earthquake occurred on a buried fault extending to the north of the Huya fault. Based on the coseismic deformation field obtained from Interferometric Synthetic Aperture Radar (InSAR) data and a series of finite fault model tests, we proposed a brand new two-fault model composed of a main fault and a secondary fault as the optimal model for the Jiuzhaigou earthquake, in which the secondary fault is at a large obtuse angle to the northern end of the main fault plane. Results show that the slip distribution is dominated by sinistral slip, with a significant shallow slip deficit. The main fault consists of two asperities, which is bounded by an aftershock gap may representing a barrier. In addition, we find that most of the aftershocks were located down-dip of the high-slip areas and laid in stress shadows. We deduce that the aftershocks may be controlled by the background tectonic stress field, and may be related to the velocity-strengthening zones.

scholarly journals On the Connection between the 2008–2009 Activation of the Koryakskii Volcano and Deep Magmatic Processes

2021 ◽  
Vol 57 (6) ◽  
pp. 819-824
Author(s):  
V. O. Mikhailov ◽  
M. S. Volkova ◽  
E. P. Timoshkina ◽  
N. M. Shapiro ◽  
V. B. Smirnov
Keyword(s):  
Continuous Monitoring ◽  
Volcanic Ash ◽  
Volcanic Edifice ◽  
Radar Interferometry ◽  
Temperature Zone ◽  
Volcanic Processes ◽  
Satellite Radar ◽  
Dip Angle ◽  
Analysis Of The Images ◽  
First Time

Abstract—The last activation of the Koryakskii volcano in 2008–2009 was accompanied by intense fumarolic and seismic activity. Volcanic activity peaked in March–April 2009 when ash plume rose to a height of 5.5 km and extended laterally over more than 600 km. To understand the dynamics of the volcanic processes and to forecast the further course of the events, it is relevant to establish whether the eruption was associated with a rise of magma to beneath the volcanic edifice or caused by fracturing of the volcano’s basement and penetration of groundwater into a high temperature zone. Based on the analysis of the images from the Japanese satellite ALOS-1 using satellite radar interferometry methods, the slope displacements of the Koryakskii volcano during its last activation have been estimated for the first time. The displacements reach 25 cm and cannot be explained by the formation of a layer of volcanic ash deposits or by the slope processes. The most likely cause of the displacements should be recognized to be the intrusion of magmatic material into the volcano edifice with the formation of a fracture with its lower edge at a depth of 0.5 km above sea level, with a size of 1.0 and 2.4 km along the strike and dip, respectively, and with a dip angle from 45° to 60°. Therefore, the processes taking place beneath the volcano can be threatening to the nearby localities and infrastructure and require continuous monitoring.

scholarly journals Displacement field and fault model for the September 7, 1999 Athens Earthquake inferred from ERS2 Satellite radar interferometry

2000 ◽  
Vol 27 (24) ◽  
pp. 3989-3992 ◽  
Author(s):  
C. Kontoes ◽  
P. Elias ◽  
O. Sykioti ◽  
P. Briole ◽  
D. Remy ◽  
...  
Keyword(s):  
Displacement Field ◽  
Fault Model ◽  
Radar Interferometry ◽  
Athens Earthquake ◽  
Satellite Radar

scholarly journals Probing the Fault Complexity of the 2017 Ms 7.0 Jiuzhaigou Earthquake Based on the InSAR Data

2021 ◽  
Vol 13 (8) ◽  
pp. 1573
Author(s):  
Xiongwei Tang ◽  
Rumeng Guo ◽  
Jianqiao Xu ◽  
Heping Sun ◽  
Xiaodong Chen ◽  
...  
Keyword(s):  
Tectonic Stress ◽  
Fault Model ◽  
Obtuse Angle ◽  
Coseismic Deformation ◽  
Jiuzhaigou Earthquake ◽  
The North ◽  
Finite Fault ◽  
Main Fault ◽  
Finite Fault Model ◽  
Secondary Fault

On 8 August 2017, a surface wave magnitude (Ms) 7.0 earthquake occurred at the buried faults extending to the north of the Huya fault. Based on the coseismic deformation field obtained from interferometric synthetic aperture radar (InSAR) data and a series of finite fault model tests, we propose a brand-new two-fault model composed of a main fault and a secondary fault as the optimal model for the Jiuzhaigou earthquake, in which the secondary fault is at a wide obtuse angle to the northern end of the main fault plane. Results show that the dislocation distribution is dominated by sinistral slip, with a significant shallow slip deficit. The main fault consists of two asperities bounded by an aftershock gap, which may represent a barrier. In addition, most aftershocks are located in stress shadows and appear a complementary pattern with the coseismic high-slip regions. We propose that the aftershocks are attributable to the background tectonic stress, which may be related to the velocity-strengthening zones.

Northridge earthquake rupture models based on the global positioning system measurements

1996 ◽  
Vol 86 (1B) ◽  
pp. S37-S48 ◽  
Author(s):  
Zheng-Kang Shen ◽  
Bob X. Ge ◽  
David D. Jackson ◽  
David Potter ◽  
Michael Cline ◽  
...  
Keyword(s):  
Global Positioning System ◽  
Fault Plane ◽  
Hanging Wall ◽  
Positioning System ◽  
Northridge Earthquake ◽  
Fault Surface ◽  
Global Positioning ◽  
Main Fault ◽  
The Moment ◽  
Secondary Fault

Abstract We use global positioning system (GPS) data to study the rupture mechanism of the 1994 Northridge earthquake in southern California. We include data from 62 observation sites, of which two (Palos Verdes and Jet Propulsion Lab) are permanent GPS geodetic array (PGGA) sites. We use a grid-search scheme to study the range of single- and dual-plane, uniform and varied slip models consistent with the data. We find that in order to fit the geodetic data with a fault model whose primary fault patch is confined to a plane through the aftershocks, a secondary fault plane is required above the primary fault plane. The moment release of the secondary fault can be as large as 1.9 × 1018 N-m, 14% of the moment release of the primary fault. This result implies significant deformation in the shallow crust associated with the mainshock. Our preferred model has a 14 × 14 array of dislocation patches on a plane through the main aftershock cluster and a 5 × 6 array of patches in the hanging wall west of the epicenter. We estimate the displacements on the patches by linear inversion with a first-order smoothness constraint. The estimated displacements on the main fault for this model are confined to a simple region between depths of 5 and 18 km, in the interior of the modeled fault surface. The mainshock lies at the bottom of the aftershock zone, near which about 1-m slip is shown on our modeled fault surface. The maximum slip on the fault surface is about 2.2 m, located at 34.28° N, 118.55° W, and 12.4 km at depth. The seismic moment release estimate of 1.34 ± 0.15 × 1019 N-m on the main fault at the 95% confidence is consistent with the estimate from strong-motion studies.

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