Sreevalsa Kolathayar | National Institute of Technology Karnataka,Surathkal (original) (raw)

Papers by Sreevalsa Kolathayar

Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016), 2016

A decade ago, in September 2006, the European Commission sanctioned Amrita University, Kerala, to... more A decade ago, in September 2006, the European Commission sanctioned Amrita University, Kerala, to design, develop, and deploy a wireless sensor network-based landslide monitoring system. The deployment was completed in June 2009, at the Anthoniar Colony Landslide in Munnar, Kerala, and the system has been in successful operation since then. Recently, the Government of India commissioned Amrita University to deploy a similar landslide monitoring system in the Himalayas. We selected the Chandmari Landslide in Gangtok City, Sikkim, as our deployment site. The deployment has been phased in two stages. The first stage, completed in June 2015, was a pilot deployment in which a 33.5 m deep borehole was drilled into rock, piezometers and inclinometers were installed, and rock samples were extracted and analyzed. Soil samples were extracted from elsewhere on the hill and tested. In the second stage, we will instrument other areas of Chandmari Hill, so that the entire region can be adequately monitored. Chandmari lies in a seismically active zone and has experienced earthquake-induced landslides in the past. In this paper, we present a thorough analysis, considering linear and gridded seismicity models and three sets of ground motion prediction equations, and estimate seismic hazard at Chandmari. In addition, we report, in detail, the results of the Chandmari soil and rock tests. We then describe a method that uses these soil and rock test results and seismic hazard analyses to estimate seismic landslide hazard at the site.

International Journal of Geotechnical Earthquake Engineering, 2015

This paper presents the seismic hazard of the state of Uttarakhand in India, located at the footh... more This paper presents the seismic hazard of the state of Uttarakhand in India, located at the foothills of the seismically active Himalayan mountain ranges. In the present study, an updated catalog of earthquakes has been prepared for Uttarakhand which was homogenized into a unified moment magnitude scale after declustering of the catalog to remove aftershocks and foreshocks. Various source zones were identified in the study area to account for local variability in seismicity characteristics. The seismicity parameters were estimated for each of these source zones, which are necessary inputs into seismic hazard estimation of a region. The seismic hazard evaluation of the region based on a state-of-the art PSHA study was performed using the classical Cornell–McGuire approach with different source models and attenuation relations. The most recent knowledge of seismic activity in the region was used to evaluate the hazard, incorporating uncertainty associated with different modeling param...

Innovative Infrastructure Solutions

Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development ... more Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development of infrastructure over time, the safety of the residence and lifeline buildings becomes a matter of concern. Bhutan lies in the Himalayan mountain ranges, which is considered one of the most active regions for seismic events. The Indian seismic code, IS 1893-2016, has assigned Zone IV for the region, which signifies the large risk that exists for all the structures. Therefore, conducting a seismic hazard assessment for the site becomes extremely necessary before any major construction. The present study focuses to perform the deterministic seismic hazard analysis (DSHA) around certain points of interest in the town of Phuentsholing, in Bhutan. Furthermore, site-specific response spectra for Pipaldhara-1, Pipaldhara-2, Kabreytar-1, Kabreytar-2 and Phuentsholing town were plotted from the results of the DSHA. It is estimated that a peak ground acceleration ranging from 0.11 to 0.14 g can be anticipated at the level of bedrock in the study region. Response spectra were plotted for the ground level using appropriate soil-amplification coefficients, derived from the analyses in the DEEPSOIL program.

Geotechnical, geological and earthquake engineering, 2022

Innovative Infrastructure Solutions

Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development ... more Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development of infrastructure over time, the safety of the residence and lifeline buildings becomes a matter of concern. Bhutan lies in the Himalayan mountain ranges, which is considered one of the most active regions for seismic events. The Indian seismic code, IS 1893-2016, has assigned Zone IV for the region, which signifies the large risk that exists for all the structures. Therefore, conducting a seismic hazard assessment for the site becomes extremely necessary before any major construction. The present study focuses to perform the deterministic seismic hazard analysis (DSHA) around certain points of interest in the town of Phuentsholing, in Bhutan. Furthermore, site-specific response spectra for Pipaldhara-1, Pipaldhara-2, Kabreytar-1, Kabreytar-2 and Phuentsholing town were plotted from the results of the DSHA. It is estimated that a peak ground acceleration ranging from 0.11 to 0.14 g can be anticipated at the level of bedrock in the study region. Response spectra were plotted for the ground level using appropriate soil-amplification coefficients, derived from the analyses in the DEEPSOIL program.

Geotechnical Characteristics of Soils and Rocks of India, 2021

Lecture Notes in Civil Engineering, 2021

This paper presents the seismic site characterization carried out for Karnataka (state level) as ... more This paper presents the seismic site characterization carried out for Karnataka (state level) as well as for India (country level) using topographic slope map derived from Digital Elevation Model (DEM) data. Two DEM data, SRTM, and ASTER were used to derive the slope maps. For Karnataka (state level), the slope map was generated from ASTER DEM considering a grid size of 5 × 5 km and for India (country level), the slope map was generated from SRTM DEM considering the grid size of 10 × 10 km. Based on the slope value, every grid point was characterized into various NEHRP site classes, and spatial variation of average shear wave velocity for top 30 m (Vs30) value throughout the study areas is presented in this paper. Peak horizontal acceleration (PHA) at bedrock level was evaluated for the same grid points using deterministic as well as probabilistic methodologies. The amplification factor for every grid point was obtained from the site coefficients corresponding to NEHRP site class. The surface level peak horizontal acceleration (PHA) was then evaluated for every grid point by multiplying bedrock level PHA with the corresponding amplification factor. Spatial variation of seismic hazard at the surface for the state of Karnataka as well as for entire India is presented in this paper.

Energy consumption takes place at each stage of pavement construction, right from extraction of r... more Energy consumption takes place at each stage of pavement construction, right from extraction of raw materials to finished products like roads. Carbon emission is an undesirable product that materializes simultaneously with energy consumption that is indispensable right through the construction activities. Reusability is another important feature that we should consider when we speak about sustainability. Though pavements made of bitumen have a higher embodied energy, it readily yields to recycling, when compared to concrete pavements, thereby reducing the energy consumed. Reducing consumed energy helps to save the resource for the future. Many situations warrant compromised sustainability when a particular type of pavement is preferred to serve a special function. In such cases, alternative materials with low embodied energy and low carbon emission may be used for the pavement design. Designs using waste materials and recycled materials would help to make energy-efficient pavements ...

Resilient Infrastructure, 2021

International Journal of Ocean and Coastal Engineering, 2019

In general, people like to live near the coast because of a better aesthetical pleasing living en... more In general, people like to live near the coast because of a better aesthetical pleasing living environment, access to a variety of recreational activities and more job opportunities. Consequently, more than 50% of the world’s population live within 200[Formula: see text]km of the coast, and ¾ of the world’s megacities are situated by the shore. Significant pressure on land, water supply, waste management and other infrastructures appear in these coastal cities. India, which hosts one-sixth of the world’s population is looking for strategies to manage India’s coastal cities, water, land and human resources. This paper reviews China’s experience in water resources development for coastal cities. China’s coastal economic corridor (CEC) contributes 60% of the national GDP, which needs plentiful water supply to sustain its coastal cities. The present investigation shows that India has better natural conditions to develop its CEC. Among the coastal infrastructures, coastal reservoirs (i.e...

International Journal of Geotechnical Earthquake Engineering, 2018

This article describes how the design of shallow foundation needs complete knowledge about bearin... more This article describes how the design of shallow foundation needs complete knowledge about bearing capacity. During earthquakes additional lateral force acts at the foundation bed which reduces the bearing capacity. Most of the literature present either the pseudo static analysis or assume a planar failure surface to estimate seismic bearing capacity factors. Here, a pseudo dynamic approach that considers the time dependent effect of earthquake loading is employed. A composite failure surface has been considered for a more realistic estimation of seismic bearing capacity. New expressions were formulated to arrive at the seismic bearing capacity factor, considering the forces acting on the failure wedge based on the limit equilibrium approach. The effect of soil friction angles and the seismic peak of horizontal ground accelerations on the seismic bearing capacity were studied using the proposed method. It was observed that present pseudo-dynamic analysis with a composite failure mec...

Comprehensive Seismic Zonation Schemes for Regions at Different Scales, 2018

This chapter describes different methodologies available for site characterization. The details o... more This chapter describes different methodologies available for site characterization. The details of different low strain and high strain tests are also listed in this chapter. It also provides procedures for the evaluation of dynamic properties from the laboratory as well as in-situ tests. Further, this chapter also presents site characterization studies carried out at micro as well as macro-level.

Lecture Notes in Civil Engineering, 2021

Indian cities are expanding not only in terms of built environment but also in population. Multi-... more Indian cities are expanding not only in terms of built environment but also in population. Multi-story buildings are rising rapidly to accommodate the growing population, undesirably even in hazard prone areas. Such a scenario calls for a proper disaster risk reduction program and plan to control the inevitable damage to lives and properties. Earthquakes are destructive only if the factors that increase the damages prevail. Attention should be given to crowded cities with people and infrastructure vulnerable to hazard. This study presents the details of deterministic seismic hazard analysis (DSHA) done for Coimbatore city of the state of Tamil Nadu, India using the latest available information on seismicity of the region. The earthquake data was compiled from different agencies and homogenized in a unified moment magnitude scale to create an updated earthquake catalog. Seismotectonic map for the study area was prepared by superimposing the earthquake events on the seismogenic source...

Proceedings of GeoShanghai 2018 International Conference: Geoenvironment and Geohazard, 2018

Indian cities are expanding not only in terms of built environment but also in population. Multi-... more Indian cities are expanding not only in terms of built environment but also in population. Multi-story buildings are rising rapidly to accommodate the growing population, undesirably even in hazard prone areas. Such a scenario calls for a proper disaster risk reduction program and plan to control the inevitable damage to lives and properties. Earthquakes are destructive only if the factors that increase the damages prevail. Attention should be given to crowded cities with people and infrastructure vulnerable to hazard. This study presents the details of deterministic seismic hazard analysis (DSHA) done for Coimbatore city of the state of Tamil Nadu, India using the latest available information on seismicity of the region. The earthquake data was compiled from different agencies and homogenized in a unified moment magnitude scale to create an updated earthquake catalog. Seismotectonic map for the study area was prepared by superimposing the earthquake events on the seismogenic sources. DSHA was then performed by dividing the study area into grids of size 0.02o × 0.02o (approximately 2 km × 2 km) using a MATLAB code, considering three different attenuation relationships for the stable continental region. Land use (LU) map for the region was developed from LANDSAT 8 data using various GIS platforms. Hazard contour map prepared using ArcGIS, was then overlaid on the LU map to comprehend the seismic risk of the region. It was observed that, though the wards south-west of the city shows higher Peak Ground Acceleration (PGA) values, the wards north-east of the city have larger and denser built-up areas, increasing its vulnerability, in the event of an earthquake.

Water Supply, 2018

This paper revisits the water resource scenario in India and presents the adequacy of the coastal... more This paper revisits the water resource scenario in India and presents the adequacy of the coastal reservoir concept to address water scarcity by impounding excess river flood waters. Although there has been no significant change in India's rainfall pattern in the last 100 years, there is a spatial non-uniformity in the rainfall events that occur which makes it difficult to pre-plan large-scale water storage at different locations. This study highlights the fact that there is enough water available but the deficiency is in storage. A large portion of freshwater from river systems, groundwater and wetlands drains into the sea due to insufficient storage facilities. Coastal reservoirs enable the storage of excess river flood waters near the coast for future use. This paper discusses current water supply solutions available in the country, and the efficacy of coastal reservoirs along with feasibility implications. The associated rewards and challenges are also discussed. The paper p...

Earthquake Hazard Assessment, 2018

Seismological Research Letters, 2012

... We created separate catalogs for each zone, and based on the threshold magnitude, estimated t... more ... We created separate catalogs for each zone, and based on the threshold magnitude, estimated the ... rate studies (Wiemer and Wyss 1997, 1997) as well as hazard-related studies (Frankel ... Another crucial development in this method is that the space-time distance is based on ...

Natural Hazards, 2013

A probabilistic seismic hazard analysis for the states of Tripura and Mizoram in North East India... more A probabilistic seismic hazard analysis for the states of Tripura and Mizoram in North East India is presented in this paper to evaluate the ground motion at bedrock level. Analyses were performed considering the available earthquake catalogs collected from different sources since 1731-2010 within a distance of 500 km from the political boundaries of the states. Earthquake data were declustered to remove the foreshocks and aftershocks in time and space window and then statistical analysis was carried out for data completeness. Based on seismicity, tectonic features and fault rupture mechanism, this region was divided into six major seismogenic zones and subsequently seismicity parameters (a and b) were calculated using Gutenberg-Richter (G-R) relationship. Faults data were extracted from SEISAT (Seismotectonic atlas of India, Geological Survey of India, New Delhi, 2000) published by Geological Survey of India and also from satellite images. The study area was divided into small grids of size 0.05°9 0.05°(approximately 5 km 9 5 km), and the hazard parameters (rock level peak horizontal acceleration and spectral accelerations) were calculated at the center of each of these grid cells considering all the seismic sources within a radius of 500 km. Probabilistic seismic hazard analyses were carried out for Tripura and Mizoram states using the predictive ground motion equations given by Atkinson and Boore (Bull Seismol Soc Am 93:1703-1729, 2003) and Gupta (Soil Dyn Earthq Eng 30:368-377, 2010) for subduction belt. Attenuation relations were validated with the observed PGA values. Results are presented in the form of hazard curve, peak ground acceleration (PGA) and uniform hazard spectra for Agartala and Aizawl city (respective capital cities of Tripura and Mizoram states). Spatial variation of PGA at bedrock level with 2 and 10 % probability of exceedance in 50 years has been presented in the paper.

Proceedings of the conference on Recent Advances in Rock Engineering (RARE 2016), 2016

A decade ago, in September 2006, the European Commission sanctioned Amrita University, Kerala, to... more A decade ago, in September 2006, the European Commission sanctioned Amrita University, Kerala, to design, develop, and deploy a wireless sensor network-based landslide monitoring system. The deployment was completed in June 2009, at the Anthoniar Colony Landslide in Munnar, Kerala, and the system has been in successful operation since then. Recently, the Government of India commissioned Amrita University to deploy a similar landslide monitoring system in the Himalayas. We selected the Chandmari Landslide in Gangtok City, Sikkim, as our deployment site. The deployment has been phased in two stages. The first stage, completed in June 2015, was a pilot deployment in which a 33.5 m deep borehole was drilled into rock, piezometers and inclinometers were installed, and rock samples were extracted and analyzed. Soil samples were extracted from elsewhere on the hill and tested. In the second stage, we will instrument other areas of Chandmari Hill, so that the entire region can be adequately monitored. Chandmari lies in a seismically active zone and has experienced earthquake-induced landslides in the past. In this paper, we present a thorough analysis, considering linear and gridded seismicity models and three sets of ground motion prediction equations, and estimate seismic hazard at Chandmari. In addition, we report, in detail, the results of the Chandmari soil and rock tests. We then describe a method that uses these soil and rock test results and seismic hazard analyses to estimate seismic landslide hazard at the site.

International Journal of Geotechnical Earthquake Engineering, 2015

This paper presents the seismic hazard of the state of Uttarakhand in India, located at the footh... more This paper presents the seismic hazard of the state of Uttarakhand in India, located at the foothills of the seismically active Himalayan mountain ranges. In the present study, an updated catalog of earthquakes has been prepared for Uttarakhand which was homogenized into a unified moment magnitude scale after declustering of the catalog to remove aftershocks and foreshocks. Various source zones were identified in the study area to account for local variability in seismicity characteristics. The seismicity parameters were estimated for each of these source zones, which are necessary inputs into seismic hazard estimation of a region. The seismic hazard evaluation of the region based on a state-of-the art PSHA study was performed using the classical Cornell–McGuire approach with different source models and attenuation relations. The most recent knowledge of seismic activity in the region was used to evaluate the hazard, incorporating uncertainty associated with different modeling param...

Innovative Infrastructure Solutions

Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development ... more Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development of infrastructure over time, the safety of the residence and lifeline buildings becomes a matter of concern. Bhutan lies in the Himalayan mountain ranges, which is considered one of the most active regions for seismic events. The Indian seismic code, IS 1893-2016, has assigned Zone IV for the region, which signifies the large risk that exists for all the structures. Therefore, conducting a seismic hazard assessment for the site becomes extremely necessary before any major construction. The present study focuses to perform the deterministic seismic hazard analysis (DSHA) around certain points of interest in the town of Phuentsholing, in Bhutan. Furthermore, site-specific response spectra for Pipaldhara-1, Pipaldhara-2, Kabreytar-1, Kabreytar-2 and Phuentsholing town were plotted from the results of the DSHA. It is estimated that a peak ground acceleration ranging from 0.11 to 0.14 g can be anticipated at the level of bedrock in the study region. Response spectra were plotted for the ground level using appropriate soil-amplification coefficients, derived from the analyses in the DEEPSOIL program.

Geotechnical, geological and earthquake engineering, 2022

Innovative Infrastructure Solutions

Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development ... more Phuentsholing is a thriving border town in the southwestern part of Bhutan. With the development of infrastructure over time, the safety of the residence and lifeline buildings becomes a matter of concern. Bhutan lies in the Himalayan mountain ranges, which is considered one of the most active regions for seismic events. The Indian seismic code, IS 1893-2016, has assigned Zone IV for the region, which signifies the large risk that exists for all the structures. Therefore, conducting a seismic hazard assessment for the site becomes extremely necessary before any major construction. The present study focuses to perform the deterministic seismic hazard analysis (DSHA) around certain points of interest in the town of Phuentsholing, in Bhutan. Furthermore, site-specific response spectra for Pipaldhara-1, Pipaldhara-2, Kabreytar-1, Kabreytar-2 and Phuentsholing town were plotted from the results of the DSHA. It is estimated that a peak ground acceleration ranging from 0.11 to 0.14 g can be anticipated at the level of bedrock in the study region. Response spectra were plotted for the ground level using appropriate soil-amplification coefficients, derived from the analyses in the DEEPSOIL program.

Geotechnical Characteristics of Soils and Rocks of India, 2021

Lecture Notes in Civil Engineering, 2021

This paper presents the seismic site characterization carried out for Karnataka (state level) as ... more This paper presents the seismic site characterization carried out for Karnataka (state level) as well as for India (country level) using topographic slope map derived from Digital Elevation Model (DEM) data. Two DEM data, SRTM, and ASTER were used to derive the slope maps. For Karnataka (state level), the slope map was generated from ASTER DEM considering a grid size of 5 × 5 km and for India (country level), the slope map was generated from SRTM DEM considering the grid size of 10 × 10 km. Based on the slope value, every grid point was characterized into various NEHRP site classes, and spatial variation of average shear wave velocity for top 30 m (Vs30) value throughout the study areas is presented in this paper. Peak horizontal acceleration (PHA) at bedrock level was evaluated for the same grid points using deterministic as well as probabilistic methodologies. The amplification factor for every grid point was obtained from the site coefficients corresponding to NEHRP site class. The surface level peak horizontal acceleration (PHA) was then evaluated for every grid point by multiplying bedrock level PHA with the corresponding amplification factor. Spatial variation of seismic hazard at the surface for the state of Karnataka as well as for entire India is presented in this paper.

Energy consumption takes place at each stage of pavement construction, right from extraction of r... more Energy consumption takes place at each stage of pavement construction, right from extraction of raw materials to finished products like roads. Carbon emission is an undesirable product that materializes simultaneously with energy consumption that is indispensable right through the construction activities. Reusability is another important feature that we should consider when we speak about sustainability. Though pavements made of bitumen have a higher embodied energy, it readily yields to recycling, when compared to concrete pavements, thereby reducing the energy consumed. Reducing consumed energy helps to save the resource for the future. Many situations warrant compromised sustainability when a particular type of pavement is preferred to serve a special function. In such cases, alternative materials with low embodied energy and low carbon emission may be used for the pavement design. Designs using waste materials and recycled materials would help to make energy-efficient pavements ...

Resilient Infrastructure, 2021

International Journal of Ocean and Coastal Engineering, 2019

In general, people like to live near the coast because of a better aesthetical pleasing living en... more In general, people like to live near the coast because of a better aesthetical pleasing living environment, access to a variety of recreational activities and more job opportunities. Consequently, more than 50% of the world’s population live within 200[Formula: see text]km of the coast, and ¾ of the world’s megacities are situated by the shore. Significant pressure on land, water supply, waste management and other infrastructures appear in these coastal cities. India, which hosts one-sixth of the world’s population is looking for strategies to manage India’s coastal cities, water, land and human resources. This paper reviews China’s experience in water resources development for coastal cities. China’s coastal economic corridor (CEC) contributes 60% of the national GDP, which needs plentiful water supply to sustain its coastal cities. The present investigation shows that India has better natural conditions to develop its CEC. Among the coastal infrastructures, coastal reservoirs (i.e...

International Journal of Geotechnical Earthquake Engineering, 2018

This article describes how the design of shallow foundation needs complete knowledge about bearin... more This article describes how the design of shallow foundation needs complete knowledge about bearing capacity. During earthquakes additional lateral force acts at the foundation bed which reduces the bearing capacity. Most of the literature present either the pseudo static analysis or assume a planar failure surface to estimate seismic bearing capacity factors. Here, a pseudo dynamic approach that considers the time dependent effect of earthquake loading is employed. A composite failure surface has been considered for a more realistic estimation of seismic bearing capacity. New expressions were formulated to arrive at the seismic bearing capacity factor, considering the forces acting on the failure wedge based on the limit equilibrium approach. The effect of soil friction angles and the seismic peak of horizontal ground accelerations on the seismic bearing capacity were studied using the proposed method. It was observed that present pseudo-dynamic analysis with a composite failure mec...

Comprehensive Seismic Zonation Schemes for Regions at Different Scales, 2018

This chapter describes different methodologies available for site characterization. The details o... more This chapter describes different methodologies available for site characterization. The details of different low strain and high strain tests are also listed in this chapter. It also provides procedures for the evaluation of dynamic properties from the laboratory as well as in-situ tests. Further, this chapter also presents site characterization studies carried out at micro as well as macro-level.

Lecture Notes in Civil Engineering, 2021

Indian cities are expanding not only in terms of built environment but also in population. Multi-... more Indian cities are expanding not only in terms of built environment but also in population. Multi-story buildings are rising rapidly to accommodate the growing population, undesirably even in hazard prone areas. Such a scenario calls for a proper disaster risk reduction program and plan to control the inevitable damage to lives and properties. Earthquakes are destructive only if the factors that increase the damages prevail. Attention should be given to crowded cities with people and infrastructure vulnerable to hazard. This study presents the details of deterministic seismic hazard analysis (DSHA) done for Coimbatore city of the state of Tamil Nadu, India using the latest available information on seismicity of the region. The earthquake data was compiled from different agencies and homogenized in a unified moment magnitude scale to create an updated earthquake catalog. Seismotectonic map for the study area was prepared by superimposing the earthquake events on the seismogenic source...

Proceedings of GeoShanghai 2018 International Conference: Geoenvironment and Geohazard, 2018

Indian cities are expanding not only in terms of built environment but also in population. Multi-... more Indian cities are expanding not only in terms of built environment but also in population. Multi-story buildings are rising rapidly to accommodate the growing population, undesirably even in hazard prone areas. Such a scenario calls for a proper disaster risk reduction program and plan to control the inevitable damage to lives and properties. Earthquakes are destructive only if the factors that increase the damages prevail. Attention should be given to crowded cities with people and infrastructure vulnerable to hazard. This study presents the details of deterministic seismic hazard analysis (DSHA) done for Coimbatore city of the state of Tamil Nadu, India using the latest available information on seismicity of the region. The earthquake data was compiled from different agencies and homogenized in a unified moment magnitude scale to create an updated earthquake catalog. Seismotectonic map for the study area was prepared by superimposing the earthquake events on the seismogenic sources. DSHA was then performed by dividing the study area into grids of size 0.02o × 0.02o (approximately 2 km × 2 km) using a MATLAB code, considering three different attenuation relationships for the stable continental region. Land use (LU) map for the region was developed from LANDSAT 8 data using various GIS platforms. Hazard contour map prepared using ArcGIS, was then overlaid on the LU map to comprehend the seismic risk of the region. It was observed that, though the wards south-west of the city shows higher Peak Ground Acceleration (PGA) values, the wards north-east of the city have larger and denser built-up areas, increasing its vulnerability, in the event of an earthquake.

Water Supply, 2018

This paper revisits the water resource scenario in India and presents the adequacy of the coastal... more This paper revisits the water resource scenario in India and presents the adequacy of the coastal reservoir concept to address water scarcity by impounding excess river flood waters. Although there has been no significant change in India's rainfall pattern in the last 100 years, there is a spatial non-uniformity in the rainfall events that occur which makes it difficult to pre-plan large-scale water storage at different locations. This study highlights the fact that there is enough water available but the deficiency is in storage. A large portion of freshwater from river systems, groundwater and wetlands drains into the sea due to insufficient storage facilities. Coastal reservoirs enable the storage of excess river flood waters near the coast for future use. This paper discusses current water supply solutions available in the country, and the efficacy of coastal reservoirs along with feasibility implications. The associated rewards and challenges are also discussed. The paper p...

Earthquake Hazard Assessment, 2018

Seismological Research Letters, 2012

... We created separate catalogs for each zone, and based on the threshold magnitude, estimated t... more ... We created separate catalogs for each zone, and based on the threshold magnitude, estimated the ... rate studies (Wiemer and Wyss 1997, 1997) as well as hazard-related studies (Frankel ... Another crucial development in this method is that the space-time distance is based on ...

Natural Hazards, 2013

A probabilistic seismic hazard analysis for the states of Tripura and Mizoram in North East India... more A probabilistic seismic hazard analysis for the states of Tripura and Mizoram in North East India is presented in this paper to evaluate the ground motion at bedrock level. Analyses were performed considering the available earthquake catalogs collected from different sources since 1731-2010 within a distance of 500 km from the political boundaries of the states. Earthquake data were declustered to remove the foreshocks and aftershocks in time and space window and then statistical analysis was carried out for data completeness. Based on seismicity, tectonic features and fault rupture mechanism, this region was divided into six major seismogenic zones and subsequently seismicity parameters (a and b) were calculated using Gutenberg-Richter (G-R) relationship. Faults data were extracted from SEISAT (Seismotectonic atlas of India, Geological Survey of India, New Delhi, 2000) published by Geological Survey of India and also from satellite images. The study area was divided into small grids of size 0.05°9 0.05°(approximately 5 km 9 5 km), and the hazard parameters (rock level peak horizontal acceleration and spectral accelerations) were calculated at the center of each of these grid cells considering all the seismic sources within a radius of 500 km. Probabilistic seismic hazard analyses were carried out for Tripura and Mizoram states using the predictive ground motion equations given by Atkinson and Boore (Bull Seismol Soc Am 93:1703-1729, 2003) and Gupta (Soil Dyn Earthq Eng 30:368-377, 2010) for subduction belt. Attenuation relations were validated with the observed PGA values. Results are presented in the form of hazard curve, peak ground acceleration (PGA) and uniform hazard spectra for Agartala and Aizawl city (respective capital cities of Tripura and Mizoram states). Spatial variation of PGA at bedrock level with 2 and 10 % probability of exceedance in 50 years has been presented in the paper.