scholarly journals ABOUT SOIL SEISMIC VIBRATIONS SPECTRA IN EARTHQUAKE NEAR ZONE

2015 ◽  
Author(s):  
Э.Г. Геодакян ◽  
С.М. Оганесян ◽  
С.Н. Саргсян ◽  
Дж.К. Карапетян
Keyword(s):  
Earthquake Source ◽  
Dynamic Parameters ◽  
Seismic Zoning ◽  
Strong Earthquakes ◽  
Earthquake Sources ◽  
Instrumental Observations ◽  
Near Zone ◽  
Seismic Vibrations ◽  
Source Physics ◽  
Seismic Impacts

Изучение спектральных и динамических параметров очагов землетрясений по данным инженерных макросейсмических и инструментальных наблюдений необходимо для решения многих задач фундамен- тальной и прикладной сейсмологии. Это задачи физики очага, процессов подготовки сильных землетря- сений, задачи сейсмического районирования, микрорайонирования, расчета сейсмических воздействий, геофизической защиты территории и т. д. Study of spectral and dynamic parameters of earthquake sources with the help of the data of engineering macroseismic and instrumental observations is necessary for many fundamental and applied seismology problems solving. These are the problems of earthquake source physics, processes of strong earthquakes origination, problems of seismic zoning, microzonation, seismic impacts calculation, geophysical protection of territory etc.

scholarly journals A project of creating atlas aftershocks of strong earthquakes

2019 ◽  
pp. 79-84
Author(s):  
A. V. Guglielmi ◽  
A. D. Zavyalov ◽  
O. D. Zotov
Keyword(s):  
Inverse Problem ◽  
Strong Earthquake ◽  
Main Shock ◽  
Earthquake Source ◽  
Problem Solution ◽  
Strong Earthquakes ◽  
Omori Law ◽  
The Earth ◽  
Interesting Possibility ◽  
Source Physics

The Omori Law, which describes the repeated underground shocks after a strong earthquake, is written in the form of a nonlinear differential equation. An idea of the focal deactivation coefficient after the main shock is introduced. Two advantages of the new wording of the Omori Law are given. Firstly, there is an interesting possibility to naturally take into account exogenous and endogenous triggers affecting the earthquake source. Endogenous triggers in the form of round-the-world seismic echo and free oscillations of the Earth, excited by the main shock, are especially noted. The second advantage is that the differential aftershock equation makes it possible to put the reverse problem of the earthquake source physics. The essence of the inverse problem is to determine the deactivation coefficient from the data on the observed aftershock frequency. Examples of inverse problem solution are given. The project of creation of the Atlas of aftershocks on the basis of the solution of the inverse problem of the source, cooling down after a strong earthquake is offered.

scholarly journals The influence of para-seismic vibrations, induced by blasting works, on structures: a Case Study

2018 ◽  
Vol 36 ◽  
pp. 02001 ◽  
Author(s):  
Wacław Andrusikiewicz
Keyword(s):  
Land Surface ◽  
Underground Mining ◽  
Control Point ◽  
Control Room ◽  
Mining Operations ◽  
Blasting Operation ◽  
Seismic Vibrations ◽  
Harmful Effects ◽  
Seismic Impacts

Underground mining operations are often associated with the necessity to use explosives. Several hundreds of kilograms of explosives, subdivided into small charges suitable for a specific mining job, are used each time in a blasting operation. In many cases, mining engineers carry out remote central blasting works, which means that all the charges placed at faces are initiated from one control point (usually, a control room in the mine) at the same time. Such coordinated explosions generate para-seismic movements whose consequences can be felt on land surface, with subsequent effects identified in buildings and structures. This paper discusses briefly selected standards applicable to the harmful para-seismic impacts. The author presents the results of the research conducted with the intention to identify harmful effects of the basting works carried out in the “Kłodawa” Salt Mine.

Joint seismic and geodetic transdimensional earthquake source optimization guided by multi-array teleseismic backprojection

2020 ◽  
Author(s):  
Andreas Steinberg ◽  
Henriette Sudhaus ◽  
Frank Krüger ◽  
Hannes Vasyura-Bathke ◽  
Simon Daout ◽  
...  
Keyword(s):  
Image Segmentation ◽  
Earthquake Source ◽  
Source Analysis ◽  
Back Projection ◽  
Source Modeling ◽  
Earthquake Sources ◽  
Good Imaging ◽  
Teleseismic Data ◽  
Segmentation Methods ◽  
Displacement Maps

<p>Earthquakes have been observed to initiate and terminate near geometrical irregularities (bends, step-overs, branching of secondary faults). Rupture segmentationinfluences the seismic radiation and therefore, the related seismic hazard. Good imaging of rupture segmentation helps to characterize fault geometries at depth for follow-up tectonic, stress-field or other analyses. From reported earthquake source models it appears that large earthquakes with magnitudes above 7 are most often segmented, while earthquakes with magnitudes below 6.5 most often are not. If this observationreflects nature or if it is rather an artifact of our abilities to well observe and infer earthquake sources can not be answered without an objective strategy to constrain rupture complexity. However, data-driven analyses of rupture segmentation are not often conducted in source modeling as it is mostly pre-defined through a given and fixed number of sources. </p><p>We, here, propose a segmentation-sensitive source analysis by combining a model-independent teleseismic back-projection and image segmentation methods with a kinematic fault inversion. Our approach is twofold. We first develop a time-domain multi-array back-projection of teleseismic data with robust estimations of uncertainties based on bootstrapping of the travel-time models and array weights (Palantiri software, https://braunfuss.github.io/Palantiri/). Backprojection has proven to be a powerful tool to infer rupture propagation from teleseismic data and identify irregularities of the rupture process over time.</p><p>We then model the earthquake sources with the results obtained from the backprojection and additional information obtained from the application of image segmentation methods to the InSAR displacement maps. For this second step, we use a combination of different observations (teleseismic waveforms and surface displacement maps based on InSAR) to increase the resolution on the spatio-temporal evolution of fault slip. We develop a novel Informational criterion based transdimensional optimization scheme to model an adequate representation of the source complexity. We present our method on two cases study: the 2016 Muji Mw 6.7 earthquake (Pamir) and the 2008-2009 Qaidam (Tibet) sequence of earthquakes. We find that the 2008 Qaidam earthquake ruptures one segment, the 2016 Muji earthquake on two segments and the Qaidam 2009 earthquake on two or three segments.</p><p>This work is based on the open-source, python-based Pyrocko toolbox and is conducted within the project “Bridging Geodesy and Seismology” (www.bridges.uni-kiel.de<http://www.bridges.uni-kiel.de>) funded by the DFG through an Emmy-Noether grant.</p><p> </p>

scholarly journals Methods and Tools of Seismic Risk Assessment and Reduction. Overview

2016 ◽  
Vol 5 (5) ◽  
pp. 75-86 ◽  
Author(s):  
Метелкин ◽  
E. Metelkin ◽  
Акатьев ◽  
Vladimir Akatev ◽  
Нигметов ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Seismic Risk ◽  
Quantitative Assessment ◽  
Seismic Events ◽  
Seismic Zoning ◽  
Chronological Order ◽  
Strong Earthquakes ◽  
Time Prediction ◽  
Proof Construction ◽  
Near Future

The article considers approaches to the analysis and management of seismic risk. In chronological order a summary of the seismographs, methods of assessing the risk of seismic events, the scale of earthquakes and seismic zoning area is presented. An expression for the quantitative assessment of seismic risk is presented. It is shown that in the management of seismic risk in Russia the researches in the field of methods for real-time prediction of strong earthquakes and earthquake-proof construction are especially relevant in the near future. The analysis of the factors that best determine the seismic risk is carried out.

scholarly journals Earthquake source arrays: optimal configuration and applications in crustal structure studies

2020 ◽  
Vol 221 (1) ◽  
pp. 352-370
Author(s):  
N Karamzadeh ◽  
S Heimann ◽  
T Dahm ◽  
F Krüger
Keyword(s):  
Search Algorithm ◽  
Synthetic Data ◽  
Velocity Model ◽  
High Energy ◽  
Earthquake Source ◽  
Origin Time ◽  
Earthquake Sources ◽  
Slowness Vector ◽  
Single Station ◽  
Source Array

SUMMARY A collection of earthquake sources recorded at a single station, under specific conditions, are considered as a source array (SA), that is interpreted as if earthquake sources originate at the station location and are recorded at the source location. Then, array processing methods, that is array beamforming, are applicable to analyse the recorded signals. A possible application is to use source array multiple event techniques to locate and characterize near-source scatterers and structural interfaces. In this work the aim is to facilitate the use of earthquake source arrays by presenting an automatic search algorithm to configure the source array elements. We developed a procedure to search for an optimal source array element distribution given an earthquake catalogue including accurate origin time and hypocentre locations. The objective function of the optimization process can be flexibly defined for each application to ensure the prerequisites (criteria) of making a source array. We formulated four quantitative criteria as subfunctions and used the weighted sum technique to combine them in one single scalar function. The criteria are: (1) to control the accuracy of the slowness vector estimation using the time domain beamforming method, (2) to measure the waveform coherency of the array elements, (3) to select events with lower location error and (4) to select traces with high energy of specific phases, that is, sp- or ps-phases. The proposed procedure is verified using synthetic data as well as real examples for the Vogtland region in Northwest Bohemia. We discussed the possible application of the optimized source arrays to identify the location of scatterers in the velocity model by presenting a synthetic test and an example using real waveforms.

scholarly journals Geomagnetic effect of earthquakes

2019 ◽  
Vol 488 (2) ◽  
pp. 197-201
Author(s):  
A. A. Spivak ◽  
S. A. Riabova
Keyword(s):  
Maximum Amplitude ◽  
Geomagnetic Disturbances ◽  
Geomagnetic Variations ◽  
Strong Earthquakes ◽  
Long Period ◽  
Geomagnetic Effect ◽  
Instrumental Observations ◽  
Short Period ◽  
Geosphere Dynamics ◽  
Academy Of Sciences

Based on the results of instrumental observations carried out at a number of mid-latitude observatories of the INTERMAGNET network and at the Mikhnevo Geophysical Observatory of Institute of Geosphere Dynamics of Russian Academy of Sciences, it is shown that strong earthquakes are accompanied by increased variations of Earth’s magnetic field. In this case, the short-period stage (period ~ 0.5-0.8 min) and long-period stage (period ~ 5-20 min) of increased geomagnetic variations are clearly distinguished. The maximum amplitude of induced geomagnetic variations is 1.5-2 nT and 2- 4 nT, respectively, for short-period and long-period variations. A similar in morphology and almost synchronous nature of the induced geomagnetic disturbances at the observatories located at significantly different distances from the earthquake source is noted.

scholarly journals SOURCE PARAMETERS of STRONG EARTHQUAKES of the EARTH

2019 ◽  
pp. 292-298 ◽  
Author(s):  
L. Chepkunas ◽  
L. Malyanova
Keyword(s):  
Seismic Moment ◽  
Source Parameters ◽  
Dynamic Parameters ◽  
Strong Earthquakes ◽  
The Earth ◽  
The World ◽  
Stress Drops ◽  
Digital Equipment

For the 19 strongest earthquakes of Russia and the world the dynamic parameters: seismic moments, lengths of ruptures, stress drops, the values of motion in the source are brought. The spectra of Р-wave were calculated on records of IRIS-IDA digital equipment at stations Obninsk-OBN, Talay-TLY, Kislovodsk-KIV in the range of epitsentralny distances of =25–82°. On the basis of the values of seismic moment Мo received on digital records at stations Obninsk-OBN, Talay-TLY, Kislovodsk-KIV, the momentny magnitude Mw (Kana-mori) are presented.

scholarly journals Active faults of the Kerch’s Peninsula: new results

2019 ◽  
Vol 488 (4) ◽  
pp. 408-412
Author(s):  
А. N. Ovsyuchenko ◽  
R. N. Vakarchuk ◽  
A. M. Korzhenkov ◽  
A. S. Larkov ◽  
А. I. Sysolin ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Strong Earthquake ◽  
Late Holocene ◽  
Active Fault ◽  
Active Faults ◽  
Fault Zones ◽  
Strong Earthquakes ◽  
Earthquake Sources ◽  
Kerch Peninsula ◽  
Seismotectonic Model

In the paper there are results of a recent study of the active faults in the Kerch Peninsula. There was compiled a Map of Active Faults - sources of the strong earthquakes occurred in Late Holocene. The map is a regional seismotectonic model of strong earthquake sources - detailed basis for a spatial prognosis of the seismic hazard. Results of the study show that the Kerch Peninsula demonstrates signs of the classical morphostructures, and a morphology of the modern peninsula contours is caused by the large active fault zones.

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