scholarly journals Average error determination in the calculation of earthquake epicenter coordinates

2021 ◽  
Vol 48 (2) ◽  
pp. 20-28
Author(s):  
G. K. Aslanov ◽  
T. G. Aslanov
Keyword(s):  
Seismic Waves ◽  
Seismic Event ◽  
Distribution Density ◽  
Specific Area ◽  
Comparison Method ◽  
Error Distribution ◽  
Average Error ◽  
Earthquake Epicenter ◽  
Seismic Sensors ◽  
Earthquake Hypocenter

Objective. The study is aimed at determining the dependence of the average error in calculating the epicenter coordinates of an earthquake on errors in measuring the velocities of seismic waves for various methods of seismic event localization. Error distribution investigation for the method for determining the earthquake hypocenter coordinates using the Cassinian oval. Methods. The problem was solved using statistical methods: methods of frequency and regression analyzes, means comparison method, and uniform search method. Results. A relationship between the accuracy of measuring the velocities of seismic waves when determining the coordinates of an earthquake epicenter were established for four different earthquake hypocenter coordinates calculation methods. A method for determining the earthquake hypocenter coordinates using the fourth-order figure of the Cassinian oval was proposed. The error distribution density of the Cassinian oval method was compared with the ones of other methods. Conclusion. The results obtained make it possible to choose one or another method for calculating the hypocenter coordinates depending on the specific area in which a seismic event occurred and the locations of seismic sensors.

scholarly journals ANOMALOUS ERRORS IN DETERMINING FOCUS COORDINATES EARTHQUAKES AND SUGGESTIONS FOR THEIR ELIMINATION

2019 ◽  
Vol 45 (4) ◽  
pp. 78-88
Author(s):  
G. K. Aslanov ◽  
T. G. Aslanov ◽  
U. A. Musaeva
Keyword(s):  
Seismic Wave ◽  
Seismic Waves ◽  
Earthquake Source ◽  
Wave Velocities ◽  
Seismic Sensors ◽  
Earthquake Hypocenter ◽  
Seismic Wave Velocities ◽  
The Times ◽  
Anomalous Errors

Objectives The aim of the study is to develop a method for estimating the speed of seismic waves in different directions of propagation and by taking into account the dimensions of the focus, reducing the error in determining the coordinates of the hypocenter. Method To find the hypocenter of the earthquake, the data of the seismic wave velocities, the differences in the times of arrival of seismic waves on seismic sensors and the error in determining the time difference are used. The data with an error determine the coordinates of the hypocenter using information from various combinations of seismic sensors. Processing the resulting array of coordinates, estimates the seismic wave velocities / or determines the spatial shape of the earthquake source and the coordinates of the hypocenter. According to the coordinates of the cinema center, the differences in the travel time of seismic waves are corrected and the distances to the seismic sensors are refined. Results After preliminary determination of the coordinates and shape of the earthquake source, if there are a large number of seismic sensors, it is possible to clarify the coordinates of the earthquake hypocenter taking into account the recommendations given in the works. Conclusion Using the proposed method implies the presence of a large number of sensors to determine the complex shape, the earthquake source. 

scholarly journals ANALYSIS OF ERROR DISTRIBUTION DENSITY IN DETERMINING THE COORDINATES OF EARTHING EARTH IN THE METHODS OF SPHERES AND ELLIPSOIDS

2019 ◽  
Vol 46 (2) ◽  
pp. 61-70
Author(s):  
T. G. Aslanov ◽  
U. A. Musaeva
Keyword(s):  
Seismic Waves ◽  
Cauchy Distribution ◽  
Error Distribution ◽  
Combined Method ◽  
Earthquake Focus ◽  
Ellipsoid Method ◽  
Earthquake Hypocenter ◽  
Error Probabilities ◽  
Method Of Ellipsoids

Objectives The purpose of the study is to obtain an expression for determining the coordinates of the earthquake focus using the ellipsoid method, as well as testing the possibility of using the method using the figures of the second order of the ellipsoid during the initial determination of the coordinates of the earthquake hypocenter.Method A comparative analysis of the probability density of errors in the hypocentral zone of the earth's surface, in combination with various spheres, ellipsoid and hyperboloid and ellipsoids, is carried out.Result Obtained an expression for determining the coordinates of the earthquake focus by the method of ellipsoids, as well as the density of the distribution of error probabilities in the determination of the earthquake hypocenter the in calculations by the method of spheres, by the combined method of spheres, hyperboloid and ellipsoid, and also by the method of ellipsoids.Conclusion Methods used to determine the coordinates of the hypocenter ellipsoid, have large errors in comparison with the method of areas. This can explained by the fact that in determining the coordinates of the hypocenter in the sphere method, three errors are used in determining the difference in the travel times of seismic waves, while in the ellipsoid method and the combined method of the sphere of the ellipsoid and hyperboloid have four errors, which introduces final errors in the distribution. All the obtained dependences of the error distribution have the form close to the Cauchy distribution. 

scholarly journals Analysis of the error distribution density convergence with its orthogonal decomposition in navigation measurements

2021 ◽  
Vol 2090 (1) ◽  
pp. 012126
Author(s):  
Igor Vorokhobin ◽  
Iryna Zhuravska ◽  
Igor Burmaka ◽  
Inessa Kulakovska
Keyword(s):  
Distribution Density ◽  
Hermite Polynomials ◽  
Gaussian Function ◽  
Cauchy Distribution ◽  
Error Distribution ◽  
Orthogonal Decomposition ◽  
Moving Object ◽  
Random Errors ◽  
Density Values ◽  
Distribution Type

Abstract Modern trends towards the expansion of online services lead to the need to determine the location of customers, who may also be on a moving object (vessel or aircraft, others vehicle – hereinafter the “Vehicle”). This task is of particular relevance in the fields of medicine – when organizing video conferencing for diagnosis and/or remote rehabilitation, e.g., for post-infarction and post-stroke patients using wireless devices, in education – when organizing distance learning and when taking exams online, etc. For the analysis of statistical materials of the accuracy of determining the location of a moving object, the Gaussian normal distribution is usually used. However, if the histogram of the sample has “heavier tails”, the determination of latitude and longitude’s error according to Gaussian function is not correct and requires an alternative approach. To describe the random errors of navigation measurements, mixed laws of a probability distribution of two types can be used: the first type is the generalized Cauchy distribution, the second type is the Pearson distribution, type VII. This paper has shown that it’s possible obtaining the decomposition of the error distribution density using orthogonal Hermite polynomials, without having its analytical expression. Our numerical results show that the approximation of the distribution function using the Gram-Charlier series of type A makes it possible to apply the orthogonal decomposition to describe the density of errors in navigation measurements. To compare the curves of density and its orthogonal decomposition, the density values were calculated. The research results showed that the normalized density and its orthogonal decomposition practically coincide.

scholarly journals Seismic Ground Response Analysis Based on Multilayer Perceptron and Convolution Neural Networks

2021 ◽  
Vol 21 (1) ◽  
pp. 231-238
Author(s):  
Seokgyeong Hong ◽  
Jaehun Ahn
Keyword(s):  
Neural Networks ◽  
Seismic Response ◽  
Multilayer Perceptron ◽  
Seismic Waves ◽  
Ground Surface ◽  
Average Error ◽  
Response Analysis ◽  
Ground Response Analysis ◽  
Analysis Process ◽  
Specific Frequency

The importance of establishing a disaster prevention plan considering seismic performance is being highlighted to reduce damage to structures caused by earthquakes. Earthquake waves propagate from the bedrock to the ground surface through the soil. During the transmission process, they are amplified in a specific frequency range, and the degree of amplification depends mainly on the characteristics of the ground. Therefore, a seismic response analysis process is essential for enhancing the reliability of the seismic design. We propose a model for predicting seismic waves on the surface from seismic waves measured on the bedrock based on Multilayer Perceptron (MLP) and Convolutional Neural Networks (CNN) and validate the applicability of the proposed model with Spectral Acceleration (SA). Both the proposed models based on MLP and CNN successfully predicted the seismic response of the surface. The CNN-based model performed better than the MLP-based model, with a 10% smaller average error. We plan to implement the physical properties of the ground, such as shear wave velocity, to create a more versatile model in the future.

scholarly journals DETERMINATION OF EARTHQUAKE FOCUS COORDINATES USING THE CASSINI OVAL METHOD WITH SECOND- AND FOURTH-ORDER HYPERBOLA FIGURES

2020 ◽  
Vol 46 (4) ◽  
pp. 134-142
Author(s):  
B. I. Shakhtarin ◽  
T. G. Aslanov ◽  
U. R. Tetakaev
Keyword(s):  
Comparative Analysis ◽  
Fourth Order ◽  
Relative Position ◽  
Seismic Waves ◽  
Arrival Times ◽  
Earthquake Focus ◽  
Seismic Sensors ◽  
Calculation Results ◽  
The Difference

Objectives. To study the dependencies obtained when determining the coordinates of an earthquake hypocentre using the figures of fourth and second orders.Method. A comparative analysis of determining the coordinates of the earthquake focus using the Cassini oval method, both taking errors in the readings of seismic sensors into account the and ignoring them, is presented.Result. A new method is proposed for determining the coordinates of the earthquake hypocentre, which uses the fourth-order figure, the Cassini oval, in the calculations. A graph is obtained for the distribution of errors in determining the coordinates of the earthquake focus (using the Cassini oval) depending on the relative position of two seismic sensors with different values of their errors in determining the difference in travel times of seismic waves.Conclusion. Since the calculation results are independent of the error sign in determining the difference in the arrival times of seismic waves, the method is suitable for the initial determination of the coordinates of the earthquake hypocentre as well as for comparison with the results of other methods for identifying the error sign. 

scholarly journals Application of Spatio-Temporal Spectral Analysis for Detection of Seismic Waves in Gravitational-Wave Interferometer

Galaxies ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 50
Author(s):  
Robert Szymko ◽  
Mateusz Denys ◽  
Tomasz Bulik ◽  
Bartosz Idźkowski ◽  
Adam Kutynia ◽  
...  
Keyword(s):  
Spectral Analysis ◽  
Seismic Waves ◽  
Noise Suppression ◽  
Frequency Range ◽  
Noise Sources ◽  
Seismic Sensors ◽  
Gravitational Wave Interferometer ◽  
Length Direction ◽  
Spatio Temporal ◽  
Measurement Period

Mixed spatio–temporal spectral analysis was applied for the detection of seismic waves passing through the west–end building of the Virgo interferometer. The method enables detection of a passing wave, including its frequency, length, direction, and amplitude. A thorough analysis aimed at improving sensitivity of the Virgo detector was made for the data gathered by 38 seismic sensors, in the two–week measurement period, from 24 January to 6 February 2018, and for frequency range 5–20 Hz. Two dominant seismic–wave frequencies were found: 5.5 Hz and 17.1 Hz. The presented method can be applied for a better understanding of the interferometer seismic environment, and by identifying noise sources, help the noise–hunting and mitigation work that eventually leads to interferometer noise suppression.

scholarly journals Estimation of the Buildings Seismic Vulnerability: A Methodological Proposal for Planning Ante-Earthquake Scenarios in Urban Areas

2018 ◽  
Vol 8 (7) ◽  
pp. 1208 ◽  
Author(s):  
José Ródenas ◽  
Salvador García-Ayllón ◽  
Antonio Tomás
Keyword(s):  
Urban Area ◽  
Urban Areas ◽  
Seismic Event ◽  
Seismic Vulnerability ◽  
Specific Area ◽  
Se Spain ◽  
Earthquake Scenarios ◽  
Emergency Situations ◽  
Emergency Scenarios ◽  
The City

In spite of the enhancements related to building construction, many regions still present a major level of seismic risk as a consequence of the high vulnerability of the urban configuration of their cities. An improved method to assess the seismic vulnerability of buildings in urban areas is proposed in this contribution in order to advance the management of seismic emergency scenarios. The methodology, mainly based on the cadastral database, allows for a more standardized implementation as a function on the typological, structural, and urban parameters of the buildings, reducing the level of uncertainties linked to these methodologies and giving continuity to the different RISK-UE published works. The generalization of the method to any urban area has also been improved by means of removing the parameters whose calibration is associated with a specific area. The methodology has been put into practice in the urban area of the city of Lorca (SE Spain), in the aftermath of the earthquake of 11 May 2011, due to the availability of well-documented data reported from this seismic event. The proposal, when it is combined with Geographic Information System (GIS) techniques, provides valuable information for the planning and management of post-earthquake emergency situations.

scholarly journals A Novel Error Compensation Method of Five-axis Flank Milling of Ruled Surface by Modifying Tool Path

2021 ◽  
Author(s):  
Gaiyun He ◽  
Chenglin Yao ◽  
Yicun Sang ◽  
Yichen Yan
Keyword(s):  
Error Compensation ◽  
Tool Path ◽  
Error Distribution ◽  
Ruled Surface ◽  
Compensation Method ◽  
Distribution Model ◽  
Flank Milling ◽  
Average Error ◽  
Machining Accuracy ◽  
Five Axis

Abstract Five-axis flank milling is widely used in the aerospace and automotive industry. However, diverse sources of errors prevent the improvement of machining accuracy. This paper proposes a novel error compensation method for five-axis flank milling of ruled surface by modifying the original tool path according to the error distribution model. The method contains three steps: First, the errors at the middle of the straight generatrix on the machined surface are calculated according to error distribution, and the corresponding normal vectors are obtained by geometric calculation. Second, multi-peaks Gaussian fitting method is utilized to make connections between parameters in the original tool path and error distribution. Finally, the new tool path is generated by adjusting original tool path. Machining experiments are performed to test the effectiveness of the proposed error compensation method. The error distribution after compensation shows that the average error decreases 74%, and the maximum error (contains overcutting and undercutting) decreases 26%. Results show that the proposed error compensation method is effective to improve the accuracy for five-axis flank milling.

scholarly journals On the footprints of a major Brazilian Amazon earthquake

2014 ◽  
Vol 86 (3) ◽  
pp. 1115-1129 ◽  
Author(s):  
ALBERTO V. VELOSO
Keyword(s):  
Seismic Waves ◽  
Seismic Event ◽  
Brazilian Amazon ◽  
Maximum Intensity ◽  
Left Bank ◽  
Seismic Parameters ◽  
Recurrence Period ◽  
Historical Accounts ◽  
Felt Area ◽  
Epicenter Location

Combining historical accounts and seismological studies, three hundred years of dormant information emerged as a source of the largest known seismic event that rocked Brazil since the beginning of our colonization. The probable epicenter location of the 1690 tremor lies on the left bank of the Amazon River, about 45 km downstream from the modern day Manaus. A year later, while passing this area, a missionary met witnesses of the tremor and observed remarkable changes in the topography and vegetation along the margin of the river. By 1692 another priest confirmed this event and the occurrence of large waves in the river, which led to the flooding of the Native Indians' terrains. The tremor spread seismic waves throughout the forest and shook indigenous constructions as far as one thousand kilometers away. A calculation of the seismic parameters shows an estimated magnitude of 7, a maximum intensity of IX MM and a felt area of about 2 million km2. Due to the long recurrence period for this type of tremor, the discovery of one of these events is valuable for seismic global intraplate studies. As for Brazil, it unravels the myth that the country was never hit by severe earthquakes.

scholarly journals Determination of coordinates of the earthquake hypocenter by the method of circles

2021 ◽  
Vol 48 (3) ◽  
pp. 52-58
Author(s):  
G. K. Aslanov ◽  
T. G. Aslanov
Keyword(s):  
Fourth Order ◽  
Intersection Point ◽  
Earthquake Source ◽  
Seismic Sensors ◽  
Earthquake Hypocenter ◽  
Source Data ◽  
Different Shapes ◽  
Intersection Line ◽  
Using Data

Objective. The aim of the study is to develop a method for determining the coordinates of the earthquake hypocenter using various combinations of second and fourth order figures as a geo-locus of the hypocenter position points.Method. It is known that the line of intersection of figures of the second and fourth orders, in the case of coincidence of focuses, is a circle. To determine the coordinates of the earthquake source, data from seismographs are used, which are used to construct figures of the second and fourth order, the intersection point of which is the hypocenter. When using data from two seismic sensors, there are two figures, the intersection line of which is a circle. A sphere with a radius equal to the radius of the circle is constructed through the center of this circle. For the other two pairs of seismic sensors, two more spheres are also formed, The intersection point of the three spheres obtained is the sought-for hypocenter of the earthquake.Result. A method has been developed for determining the coordinates of an earthquake source using different shapes of the second and fourth orders for different pairs of seismic sensors.Conclusion. The method allows one to select one of the second or fourth order figures for different pairs of seismic sensors, which makes it possible to reduce the error in determining the source coordinates.

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