scholarly journals First level seismic microzonation map of Chennai city – a GIS approach

2011 ◽  
Vol 11 (2) ◽  
pp. 549-559 ◽  
Author(s):  
G. P. Ganapathy
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Tamil Nadu ◽  
Cultural Development ◽  
Seismic Microzonation ◽  
Seismic Sources ◽  
Ground Acceleration ◽  
Hazard Zone ◽  
Chennai City ◽  
The City

Abstract. Chennai city is the fourth largest metropolis in India, is the focus of economic, social and cultural development and it is the capital of the State of Tamil Nadu. The city has a multi-dimensional growth in development of its infrastructures and population. The area of Chennai has experienced moderate earthquakes in the historical past. Also the Bureau of Indian Standard upgraded the seismic status of Chennai from Low Seismic Hazard (Zone II) to Moderate Seismic Hazard (Zone III)–(BIS: 1893 (2001)). In this connection, a first level seismic microzonation map of Chennai city has been produced with a GIS platform using the themes, viz, Peak Ground Acceleration (PGA), Shear wave velocity at 3 m, Geology, Ground water fluctuation and bed rock depth. The near potential seismic sources were identified from the remote-sensing study and seismo-tectonic details from published literatures. The peak ground acceleration for these seismic sources were estimated based on the attenuation relationship and the maximum PGA for Chennai is 0.176 g. The groundwater fluctuation of the city varies from 0–4 m below ground level. The depth to bedrock configuration shows trough and ridges in the bedrock topography all over the city. The seismic microzonation analysis involved grid datasets (the discrete datasets from different themes were converted to grids) to compute the final seismic hazard grid through integration and weightage analysis of the source themes. The Chennai city has been classified into three broad zones, viz, High, Moderate and Low Seismic Hazard. The High seismic Hazard concentrated in a few places in the western central part of the city. The moderate hazard areas are oriented in NW-SE direction in the Western part. The southern and eastern part will have low seismic hazard. The result of the study may be used as first-hand information in selecting the appropriate earthquake resistant features in designing the forthcoming new buildings against seismic ground motion of the city.

scholarly journals GIS APPROACH GEOSPATIAL APPLICATION FOR SEISMIC MICROZONATION STUDY

2018 ◽  
Author(s):  
Г.П. Ганапатхи ◽  
В.Б. Заалишвили ◽  
Д.А. Мельков ◽  
В.Б. Свалова ◽  
А.В. Николаев
Keyword(s):  
Seismic Hazard ◽  
Shear Wave ◽  
Peak Ground Acceleration ◽  
Seismic Microzonation ◽  
Exceedance Probability ◽  
Ground Acceleration ◽  
Shear Wave Velocities ◽  
Gis Technique ◽  
Rock Depth ◽  
Chennai City

В работе представлен инструментарий в виде ГИС-технологий для составления карты сейсмического микрорайонирования. Рассмотрены методы и способы индийской и российской практики сейсмического микрорайонирования Реализована компиляция исходных данных в оперативную экспресс ГИС-методику. Построена карта сейсмического микрорайонирования первого уровня для города Ченнаи (Индия) с использованием ГИС-платформы на основе использования специфических информационных слоев в виде пикового ускорения грунта (PGA), скорости поперечной волны, геологического строения территории, уровня грунтовых вод и глубины кровли подстилающих коренных пород. Пиковое ускорение для сейсмических источников оценивалось на основе отношения затухания. При этом максимальное ускорение PGA для Ченнаи составило 0,176 g, а для Владикавказа – 0,2 g (для вероятности превышения 5%). Анализ сейсмической опасности включал матрицы данных (дискретные наборы данных из разных тем были преобразованы в сетки) для расчета окончательной матрицы сейсмической опасности путем интеграции и анализа веса исходных тематических слоев. Город Ченнай в процессе исследования был разделен на три обширные зоны: высокой, умеренной и низкой сейсмической опасности. Карта сейсмического микрорайонирования города Владикавказа была представлена в единицах шкалы MSK-64 и единицах ускорения. В обоих рассмотренных подходах скорости поперечных волн были одной из основных инструментальных основ для соответствующих расчетов. Используя в качестве исходных данных сценариев синтезированные расчетные записи с учетом характеристик неисправностей, учитывается трансформация исходных акселерограмм, обусловленных свойствами почвы на территории. In the paper GIS approach for seismic microzonation map compilation is presented. Approaches of Indian and Russian seismic microzonation practice are considered and compilated in express GIS technique. A first level seismic microzonation map of Chennai city has been produced with a GIS platform using the themes, viz, Peak Ground Acceleration (PGA), Shear wave velocity at 3 m, Geology, Ground water fluctuation and bed rock depth. The peak ground acceleration for these seismic sources were estimated based on the attenuation relationship and the maximum PGA for Chennai is 0.176 g and for Vladikavkaz 0.2 g (for 5% exceedance probability). The seismic microzonation analysis involved grid datasets (the discrete datasets from different themes were converted to grids) to compute the final seismic hazard grid through integration and weightage analysis of the source themes. The Chennai city has been classified into three broad zones, viz, High, Moderate and Low Seismic Hazard. Vladikavkaz city microzonation map was presented in MSK-64 scale. In both approaches shear wave velocities was one of the basic instrumental data. Using as initial data of the scenario synthesized records, taking into account the characteristics of faults, takes into account the transformation of the original accelerograms stipulated by soil properties of the territory.

scholarly journals Scenario-based earthquake hazard and risk assessment for Baku (Azerbaijan)

2010 ◽  
Vol 10 (12) ◽  
pp. 2697-2712 ◽  
Author(s):  
G. Babayev ◽  
A. Ismail-Zadeh ◽  
J.-L. Le Mouël
Keyword(s):  
Risk Assessment ◽  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Water Level Fluctuations ◽  
Industrial Building ◽  
Earthquake Risk ◽  
Population Exposure ◽  
Ground Acceleration ◽  
Earthquake Scenarios ◽  
The City

Abstract. A rapid growth of population, intensive civil and industrial building, land and water instabilities (e.g. landslides, significant underground water level fluctuations), and the lack of public awareness regarding seismic hazard contribute to the increase of vulnerability of Baku (the capital city of the Republic of Azerbaijan) to earthquakes. In this study, we assess an earthquake risk in the city determined as a convolution of seismic hazard (in terms of the surface peak ground acceleration, PGA), vulnerability (due to building construction fragility, population features, the gross domestic product per capita, and landslide's occurrence), and exposure of infrastructure and critical facilities. The earthquake risk assessment provides useful information to identify the factors influencing the risk. A deterministic seismic hazard for Baku is analysed for four earthquake scenarios: near, far, local, and extreme events. The seismic hazard models demonstrate the level of ground shaking in the city: PGA high values are predicted in the southern coastal and north-eastern parts of the city and in some parts of the downtown. The PGA attains its maximal values for the local and extreme earthquake scenarios. We show that the quality of buildings and the probability of their damage, the distribution of urban population, exposure, and the pattern of peak ground acceleration contribute to the seismic risk, meanwhile the vulnerability factors play a more prominent role for all earthquake scenarios. Our results can allow elaborating strategic countermeasure plans for the earthquake risk mitigation in the Baku city.

scholarly journals An extended stochastic method for seismic hazard estimation

2015 ◽  
Vol 3 (12) ◽  
pp. 7555-7586
Author(s):  
A. K. Abd el-aal ◽  
M. A. El-Eraki ◽  
S. I. Mostafa
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Peak Ground Acceleration ◽  
Risk Mitigation ◽  
Stochastic Method ◽  
Soil Conditions ◽  
Seismic Sources ◽  
Ground Acceleration ◽  
Median Response

Abstract. In this contribution, we developed an extended stochastic technique for seismic hazard assessment purposes. This technique depends on the hypothesis of stochastic technique of Boore (2003) "Simulation of ground motion using the stochastic method. Appl. Geophy. 160:635–676". The essential characteristics of extended stochastic technique are to obtain and simulate ground motion in order to minimize future earthquake consequences. The first step of this technique is defining the seismic sources which mostly affect the study area. Then, the maximum expected magnitude is defined for each of these seismic sources. It is followed by estimating the ground motion using an empirical attenuation relationship. Finally, the site amplification is implemented in calculating the peak ground acceleration (PGA) at each site of interest. We tested and applied this developed technique at Cairo, Suez, Port Said, Ismailia, Zagazig and Damietta cities to predict the ground motion. Also, it is applied at Cairo, Zagazig and Damietta cities to estimate the maximum peak ground acceleration at actual soil conditions. In addition, 0.5, 1, 5, 10 and 20 % damping median response spectra are estimated using the extended stochastic simulation technique. The calculated highest acceleration values at bedrock conditions are found at Suez city with a value of 44 cm s−2. However, these acceleration values decrease towards the north of the study area to reach 14.1 cm s−2 at Damietta city. This comes in agreement with the results of previous studies of seismic hazards in northern Egypt and is found to be comparable. This work can be used for seismic risk mitigation and earthquake engineering purposes.

scholarly journals Seismic hazard assessment of Iran

1999 ◽  
Vol 42 (6) ◽  
Author(s):  
B. Tavakoli ◽  
M. Ghafory-Ashtiany
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Grid Point ◽  
Seismic Hazard Assessment ◽  
Earthquake Hazard ◽  
Seismic Source ◽  
Historical Earthquakes ◽  
Earthquake Insurance ◽  
Ground Acceleration ◽  
Seismic Source Models

The development of the new seismic hazard map of Iran is based on probabilistic seismic hazard computation using the historical earthquakes data, geology, tectonics, fault activity and seismic source models in Iran. These maps have been prepared to indicate the earthquake hazard of Iran in the form of iso-acceleration contour lines, and seismic hazard zoning, by using current probabilistic procedures. They display the probabilistic estimates of Peak Ground Acceleration (PGA) for the return periods of 75 and 475 years. The maps have been divided into intervals of 0.25 degrees in both latitudinal and longitudinal directions to calculate the peak ground acceleration values at each grid point and draw the seismic hazard curves. The results presented in this study will provide the basis for the preparation of seismic risk maps, the estimation of earthquake insurance premiums, and the preliminary site evaluation of critical facilities.

scholarly journals A STUDY ON SOCIO-ECONOMIC CONDITIONS OF SLUM HOUSEHOLDS WITH SPECIAL REFERENCE TO PORUR SLUM AREA, CHENNAI CITY

YMER Digital ◽  
2021 ◽  
Vol 20 (12) ◽  
pp. 439-445
Author(s):  
V Thandapani ◽  
◽  
M Arulmurugan ◽  
Keyword(s):  
Special Reference ◽  
Urban Areas ◽  
Tamil Nadu ◽  
Social Deprivation ◽  
Economic Conditions ◽  
Slum Area ◽  
State Expansion ◽  
Chennai City ◽  
The City ◽  
Push Factor

The dimension of the slums is presumed as something that is deteriorating urban areas that is densely populated and contains dilapidated housing, often in multiple occupations, poverty, social disadvantage and other forms of physical and social deprivation. Sprawl is a universal occurrence knowledgeable by inexpensively highly developed fine mounting nations. Hurried sprawl appropriate to “pull factor” or the livelihood occasion fashioned in the city and “push factor” owed to the be deficient in of the equivalent in rustic regions and together with ecological dilapidation, has fascinated settlers not barely as of the rustic state but in addition commencing supplementary fractions of the state. Expansion of mechanization roughly in capital of Tamil Nadu, in deprivation condition in the rustic locale, too little drizzle in the rustic part, castism, hastily and enormous edifice creation doings and approximately the city and in sequence expertise commons, has specified surety for accomplished, inexperienced, semi-skilled employments are existing to the justified citizens. In the present study main aims are income and expenditure activities of the Porur slum areas in Chennai city

Evaluation of Peak Ground Acceleration and Response Spectra Considering the Local Site Effects

2010 ◽  
Vol 1 (1) ◽  
pp. 25-41 ◽  
Author(s):  
T. G. Sitharam ◽  
K. S. Vipin
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Site Effects ◽  
Response Spectra ◽  
Probabilistic Logic ◽  
Site Classification ◽  
Ground Acceleration ◽  
Entire Study ◽  
Local Site Effects ◽  
Local Site

The local site effects play an important role in the evaluation of seismic hazard. The proper evaluation of the local site effects will help in evaluating the amplification factors for different locations. This article deals with the evaluation of peak ground acceleration and response spectra based on the local site effects for the study area. The seismic hazard analysis was done based on a probabilistic logic tree approach and the peak horizontal acceleration (PHA) values at the bed rock level were evaluated. Different methods of site classification have been reviewed in the present work. The surface level peak ground acceleration (PGA) values were evaluated for the entire study area for four different site classes based on NEHRP site classification. The uniform hazard response spectrum (UHRS) has been developed for the city of Bangalore and the details are presented in this work.

Estimation of Peak Ground Acceleration and Its Uncertainty for Northern Indian Region

2011 ◽  
Vol 2 (1) ◽  
pp. 1-19 ◽  
Author(s):  
Girish Chandra Joshi ◽  
Mukat Lal Sharma
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Indian Region ◽  
Branch Points ◽  
Logic Tree ◽  
Ground Acceleration ◽  
Source Models ◽  
Hazard Parameters

In the present study the authors evaluate uncertainties in the seismic hazard assessment for the Northern Indian region, based on the probabilistic seismic hazard analysis (PSHA). The newly compiled earthquake data has been treated for the quality, consistency, and homogeneity in a systematic manner to find out the uncertainties in every step of calculations. Based on the geological and tectonic setup, seismicity and other geophysical anomalies, a seismotectonic model of the region has been developed. The seismic hazard parameters are calculated based on giving proper weight to specific region. The peak ground acceleration (PGA) is estimated for various return periods for the Northern Indian region using a logic tree approach. The variation at the input level in terms of the source models and different Ground Motion Prediction Equations (GMPEs) is used. To examine into the effect of source modelling and GMPEs, the Coefficient of Variation (COV) maps have been generated. To encompass the region and for better resolution, the peak ground acceleration (PGA) is estimated at 15 minute intervals. The COV values due to all branch points in the logic tree decrease with distance from the source and conspicuous increase toward fault boundaries are observed.

scholarly journals Peak ground acceleration at surface for Mataram city with a return period of 2500 years using probabilistic method

2018 ◽  
Vol 195 ◽  
pp. 03019
Author(s):  
Rian Mahendra Taruna ◽  
Vrieslend Haris Banyunegoro ◽  
Gatut Daniarsyad
Keyword(s):  
Seismic Hazard ◽  
Return Period ◽  
Peak Ground Acceleration ◽  
Subduction Zones ◽  
Amplification Factor ◽  
Hazard Analysis ◽  
Probabilistic Method ◽  
Seismic Zone ◽  
Ground Acceleration ◽  
Back Arc

The Lombok region especially Mataram city, is situated in a very active seismic zone because of the existence of subduction zones and the Flores back arc thrust. Hence, the peak ground acceleration (PGA) at the surface is necessary for seismic design regulation referring to SNI 1726:2012. In this research we conduct a probabilistic seismic hazard analysis to estimate the PGA at the bedrock with a 2% probability of exceedance in 50 years corresponding to the return period of 2500 years. These results are then multiplied by the amplification factor referred from shear wave velocity at 30 m depth (Vs30) and the microtremor method. The result of the analysis may describe the seismic hazard in Mataram city which is important for building codes.

scholarly journals Estimation of peak ground acceleration and spectral acceleration for South India with local site effects: probabilistic approach

2009 ◽  
Vol 9 (3) ◽  
pp. 865-878 ◽  
Author(s):  
K. S. Vipin ◽  
P. Anbazhagan ◽  
T. G. Sitharam
Keyword(s):  
Seismic Hazard ◽  
Peak Ground Acceleration ◽  
South India ◽  
Hazard Analysis ◽  
Shear Zones ◽  
Spectral Acceleration ◽  
Ground Acceleration ◽  
Site Class ◽  
Probability Of Exceedance ◽  
Grid Points

Abstract. In this work an attempt has been made to evaluate the seismic hazard of South India (8.0° N–20° N; 72° E–88° E) based on the probabilistic seismic hazard analysis (PSHA). The earthquake data obtained from different sources were declustered to remove the dependent events. A total of 598 earthquakes of moment magnitude 4 and above were obtained from the study area after declustering, and were considered for further hazard analysis. The seismotectonic map of the study area was prepared by considering the faults, lineaments and the shear zones in the study area which are associated with earthquakes of magnitude 4 and above. For assessing the seismic hazard, the study area was divided into small grids of size 0.1°×0.1°, and the hazard parameters were calculated at the centre of each of these grid cells by considering all the seismic sources with in a radius of 300 km. Rock level peak horizontal acceleration (PHA) and spectral acceleration (SA) values at 1 s corresponding to 10% and 2% probability of exceedance in 50 years have been calculated for all the grid points. The contour maps showing the spatial variation of these values are presented here. Uniform hazard response spectrum (UHRS) at rock level for 5% damping and 10% and 2% probability of exceedance in 50 years were also developed for all the grid points. The peak ground acceleration (PGA) at surface level was calculated for the entire South India for four different site classes. These values can be used to find the PGA values at any site in South India based on site class at that location. Thus, this method can be viewed as a simplified method to evaluate the PGA values at any site in the study area.

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