Seismic Hazard Assessment and Numerical Modeling for Seismic Microzonation purpose of Dushanbe, Tajikistan

2020 ◽  
Author(s):  
Farkhod Hakimov ◽  
Hans-Balder Havenith ◽  
Anatoly Ischuk ◽  
Marco Pilz ◽  
Klaus Reicherter
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Urban Areas ◽  
Seismic Hazard Assessment ◽  
Seismic Microzonation ◽  
Soil Conditions ◽  
Seismic Action ◽  
City Area ◽  
Local Soil ◽  
Local Soil Conditions

<p>Seismic hazard assessment of urban areas is an important and extremely challenging task. It is so important because without the knowledge of the influence of local soil conditions and properties, of the changing layer thickness in urban areas, and without considering multiple possible scenario earthquakes for this territory, engineers do not have enough information on how to design and construct seismically safe buildings. The particular challenge of this task is due to the great uncertainty affecting the prediction of the spatially (and sometimes even temporally) changing seismic properties of soils with respect to urban development.<br>Dushanbe is the capital of Tajikistan, a mountainous country marked by high to very high seismic hazard. The reason for the high seismic hazard specifically near Dushanbe is related to its location between two fault systems: South Gissar fault and Ilek-Vaksh fault.  Estimation of the seismic hazard of the urban areas in Tajikistan is very important because they had developed in a very short time and many high buildings are being constructed now Existing seismic action estimations are based on the old approaches when the main factors of the local soil conditions only consider general engineering-geological features of the territory as well as macro-seismic observations data. An additional problem is the building code in Tajikistan; it uses the estimation of the ground motions in terms of the MSK-64 scale, but does not enough take into account the variety of the soil conditions in the Dushanbe city area. Existing seismic hazard estimation of the area of Tajikistan is based on the so-called “The map of general seismic zoning of the territory of Tajikistan”, that was produced in 1978 in terms of MSK-64 scale. The seismic microzonation map of the Dushanbe city area was made in 1975 in terms of MSK-64 scale as well and was based on the engineering-geological approach mostly. This map does not represent the highly variable soil conditions of the Dushanbe city area which are partly due to the anthropogenic influence of the large city. Therefore, earlier seismic zonation maps assigned an intensity of IX to most districts of the city. However, those previous studies did not sufficiently quantify the local effects of soils on the seismic hazard, mainly the macro-seismic conditions (the relative distance of districts to fault lines) were considered for the zonation. <br>This study describes and implements a number of new approaches to the evaluation of maximum seismic impact and site effect values. </p>

scholarly journals ON THE POSSIBILITY OF ASSESSING SEISMIC HAZARD FOR OFFSHORE CONSTRUCTIONS ON THE CASPIAN SHELF BY CALCULATION METHODS

2020 ◽  
Vol 4(48) ◽  
pp. 21-35
Author(s):  
B.A. Trifonov ◽  
◽  
S.Yu. Milanovsky ◽  
I.A. Mindel ◽  
V.V. Nesinov ◽  
...  
Keyword(s):  
Seismic Hazard ◽  
Computational Methods ◽  
Caspian Sea ◽  
Oil And Gas ◽  
Spectral Composition ◽  
Seismic Hazard Assessment ◽  
Offshore Structures ◽  
Soil Conditions ◽  
Seismic Microzoning ◽  
Local Soil

In recent years the world has been actively developing oil and gas fields on the shelf, including in seismically active areas. On the seabed it is very difficult to carry out qualitative geological and geophysical studies and seismological observations in full, which are a part of seismic microzoning works. Programs for computational methods during seismic microzoning allow taking into account nonlinear soil properties. In the article the experience of studies on seismic microzoning (2012–2015) for the installation area of offshore structures on the shelf of the Middle Caspian Sea is considered. In conditions of absence of observations by bottom seismic stations the possibility of seismic hazard assessment by computational methods taking into account local soil conditions is shown. Thus the obtained values of seismic intensity are lower in comparison with the results of estimations by method of engineering and geological analogies and method of seismic rigidity. Maximal impacts from zones of possible earthquake sources most dangerous for Middle Caspian Sea have been taken into account by peculiarities of spectral composition of vibrations of ground bases in the form of reaction spectra.

Up-to-Date of Seismic Design Spectrum for Offshore Platforms at the Bay of Campeche

2003 ◽  
Author(s):  
Joel A. Garci´a Vargas ◽  
Roberto Pe´rez Marti´nez
Keyword(s):  
Seismic Hazard ◽  
Seismic Design ◽  
Soil Conditions ◽  
Reserve Capacity ◽  
Seismic Action ◽  
Offshore Platforms ◽  
Local Conditions ◽  
Design Spectrum ◽  
Earthquake Sources ◽  
Local Soil

This paper presents the procedure proposed by the ISO code adapted to the local conditions in the Bay of Campeche, Mexico in order to obtain design spectrum for different seismic reserve capacity factors. A probabilistic seismic hazard analyses is used in order to determine the uniform hazard spectrum where the seismic environment, according to previous researches, is influenced by three primary types of earthquake sources: the subduction zone on the western pacific coast of Mexico, the lithospheric slab within the central portion of Mexico and the trans-mexican volcanic belt. This earthquake spatial distribution can be shown trough the historic catalog of earthquake occurrences during the period 1900–2001 used. On the one hand, in the evaluation of the characteristics and the uncertainties associated with the earthquake sources and their effects on the interest sites, are taken into account the characterization of the earthquake sources, the effect of the seismic wave propagation, the local conditions and the soil-structure interaction developed during earthquake ground motions. On the other hand, the uncertainties on the seismic hazard curve and those associated with the platform behavior (mass, stiffness, damping) in which their values are assigned to be consistent with the ISO 19901-2 and ISO 19902 seismic code suggestions. The final result consists in a seismic design spectrum for offshore platforms at the Bay of Campeche, which are consistent with the recommended ISO 19902 seismic reserve capacity factors, modified for local soil conditions, following a detailed seismic-action procedure.

scholarly journals A Low-Cost Instrumentation System for Seismic Hazard Assessment in Urban Areas

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3618
Author(s):  
Vassilis K. Papanikolaou ◽  
Christos Z. Karakostas ◽  
Nikolaos P. Theodoulidis
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Urban Areas ◽  
Low Cost ◽  
Strong Motion ◽  
Seismic Hazard Assessment ◽  
Real Field ◽  
Dense Network ◽  
Area Of Interest ◽  
Ultra Dense Network

The development and application of a low-cost instrumentation system for seismic hazard assessment in urban areas are described in the present study. The system comprises a number of autonomous triaxial accelerographs, designed and manufactured in house and together with dedicated software for device configuration, data collection and further postprocessing. The main objective is to produce a detailed view of strong motion variability in urban areas, for at least light intensity strong motion events. The overall cost of the developed devices is at least ten times lower than the respective commercial units, hence their deployment as an ultra-dense network over the area of interest can be significantly cost-effective. This approach is considered an efficient complement to traditional microzonation procedures, which are typically based on relatively few actual recordings and the application of theoretical methodologies to assess the strong motion distribution. The manufactured devices adopt micro-electro-mechanical (MEMS) digital sensor technology for recording acceleration, whereas the accompanying software suite provides various configuration options, quick browsing, analyzing and exporting of the recorded events, as well as GIS type functionality for seamlessly producing explicit seismic hazard maps of the considered area. The evaluation of system performance was based on shaking table and real field comparisons against high accuracy commercial accelerographs. The study concludes with a real application of the proposed system in the form of an ultra-dense network installed at the city of Lefkada, an earthquake prone urban area in Greece, and the following compilation of explicit shakemaps.

scholarly journals Монгол орны нутал дэвсгэрт бүртгэгдсэн газар хөдлөлтийн төвүүдийн нягтаршил

2017 ◽  
pp. 3-13
Author(s):  
Баяраа Г ◽  
А В Ключевский ◽  
Дэмбэрэл С
Keyword(s):  
Spatial Distribution ◽  
Seismic Hazard ◽  
Hazard Assessment ◽  
Urban Areas ◽  
Seismic Activity ◽  
Seismic Hazard Assessment ◽  
Earthquake Epicenter ◽  
Assessment Study ◽  
Active Zones ◽  
Instrumental Period

Map of earthquake epicenter density of Mongolia for the instrumental period (1964 - 2000) is presented. Seismic active zones are studied using information provided by the location of earthquake epicenters density. The results suggest that Mongolian territory could be divided into five seismic active and homogeneous sub- zones originated by the distribution of seismic active Cenozoic faults and epicenter density. Earthquake epicenter density and its spatial distribution are given a possibility to define and localize seismic active zones, current seismic pattern and its future dynamics of seismic activity in these zones. Most of earthquakes with the larger magnitude in the seismic active zones occurred in proximity to the statistically identified potential faults. Results of this study would be input parameters of seismic hazard assessment study of urban areas.

scholarly journals Seismic hazard assessment for the underwater gas pipeline route in the water area of the Nevelskoy Strait

Vestnik MGTU ◽  
2021 ◽  
Vol 24 (1) ◽  
pp. 14-34
Author(s):  
S. A. Kovachev ◽  
A. A. Krylov
Keyword(s):  
Seismic Hazard ◽  
Hazard Assessment ◽  
Oil And Gas ◽  
Seismic Hazard Assessment ◽  
Gas Pipeline ◽  
Soil Conditions ◽  
Seismic Zoning ◽  
Seismic Effects ◽  
Seismic Microzoning ◽  
Pipeline Route

The presence of seismic threat multiplies the environmental hazard, especially for oil and gas production and transport facilities in water areas. Currently, there are no normative maps of general seismic zoning of the water areas of the inland and marginal seas of Russia, especially since there are practically no maps of detailed seismic zoning and seismic microzoning of even individual parts of the water areas. Taking into account the fact that intensive development of offshore oil and gas fields and the Northern Sea Route has begun, the development of such maps becomes a very urgent scientific and practical task. The seismic hazard assessment for the submerged crossing was carried out in 2008. The initial seismic effects were calculated using a probabilistic seismic hazard analysis based on five models of seismic zones and three types of models of attenuation of peak and spectral accelerations. The results of the performed calculations, including deaggregation, have shown that the initial seismicity of the area of the gas pipeline crossing route through the Nevelskoy Strait for a return period of 1,000 years is lower than indicated on the OSR-2016-B map, where the eastern end of the crossing route through the strait is characterized by the initial seismicity equal to 9 points. The soil conditions (seismic microzoning) have been taken into account by three different methods: the seismic rigidity method, the calculation method, and the method considering the thickness of Quaternary deposits. The present studies show that seismic effects vary along the pipeline route from the mainland to Sakhalin Island from 8.4 to 8.9 on the MSK-64 scale for the recurrence period of seismic shaking T = 1,000 years and from 9.3 to 9.7 points for T = 5,000 years.

scholarly journals USAGE OF PROGRAM ALGORYTHMIC TOOL OF OSR-97 METHODIC IN DETAILED SEISMIC ZONING PROBLEMS

2015 ◽  
Author(s):  
С.А. Перетокин
Keyword(s):  
Seismic Hazard ◽  
Russian Federation ◽  
Hazard Assessment ◽  
Seismic Hazard Assessment ◽  
Soil Conditions ◽  
Seismic Zoning ◽  
The Russian Federation ◽  
Detailed Seismic Zoning

В Российской Федерации исторически сложилась двухступенчатая схема оценки сейсмической опас- ности - оценка исходной сейсмичности для средних грунтов и последующая корректировка оценок с уче- том реальных грунтовых условий площадки Historically in the Russian Federation formed two-staged assessment scheme of seismic hazard assessment of the initial seismicity for average soils and the following correction of assessments with accounting of site real soil conditions

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