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This paper presents a methodology to identify the controlling parameters of rainfall-induced landslides. Two laboratory scale model of a typical slope has been created with the help of a tilting flume setup incorporated with rainfall simulators to understand the landslide fluidization process using various sensors and cameras. The results obtained with this study will help determine the most efficient monitoring parameters to be considered for developing a landslide early warning system (LEWS). The tilting flume setup was created with 45-degree and 60-degree slopes. The pore water pressure parameters were measured, and instantaneous photographs were taken continuously after simulating artificial rainfall using rainfall simulators. The landslide mechanics that cause the initiation of soil movement have been closely monitored. The summary of this study will help develop an early warning system for landslide-prone regions. The findings of this study emphasize that pore water pressure monitoring is not the best method to develop an early warning system as the pressure values are unpredictable in a massive heterogeneous soil body and sloping angle. However, there is a sudden release of pore pressure right after the failure of the mass, which is evident from the results obtained.

Recently developed region-specific GMPEs are used for a comprehensive seismic hazard analysis (SHA) of the North and Central Himalayas (NCH) using a probabilistic approach considering two source models. Vulnerable seismic sources in the areas are identified based on the Seismotectonic Atlas (Dasgupta et al. 2000), published by the Geological Survey of India. An up to date, homogenized and declustered earthquake catalogue is compiled from various sources, with earthquake data since 250 BC, to create a new digitized seismotectonic representation of the region. Regional seismic zones having similar seismicity are recognized based on the Gutenberg-Richter (GR) parameters and the region is delineated into 5 seismic zones. The study area is divided into grids of size 0.05° × 0.05° and the hazard in terms of Peak Ground Acceleration (PGA) at the centre of each grid point is estimated and presented as hazard maps for individual seismic sources, maximum of all sources, and average of both sources. From the current study, it could be concluded that the PGA estimated in the regions is comparatively higher than what is reported in the codal provisions for seismic zonation and estimation of design horizontal acceleration for the region.

This paper makes an attempt to review historical and recent seismicity in Delhi and presents updated seismic hazard map of Delhi integrated with ward-wise classified population data. Earthquakes are not destructive unless other factors that enhance the damage prevail. Population density and types or quality of buildings in an area are two such important factors that affect the risk during any hazards, particularly an earthquake. This paper presents the details of the seismic hazard analysis for Delhi with the latest available information on earthquakes and seismic sources within 300 km radius around the city, using state-of-the-art deterministic approach. Ten different attenuation relationships developed for the active tectonic region were considered in the present study. They were ranked using log-likelihood method. Ward-wise population maps along with classified population maps were developed based on the 2011 census data. Hazard contour map and population maps are presented in this paper to revisit the seismic risk prevailing in the region. An attempt was made to overlay the hazard map with population maps showing the distribution of various classes of the population that reflects the seismic risk exposure to different wards of Delhi.

This paper presents an overview of Thanneermukkom bund with its implications on water security in the region as a freshwater reservoir in the southwest coast of India. The bund was constructed in 1...

In the present study, the Probabilistic Seismic Hazard Analysis (PSHA) has been carried out for a powerplant site in Chittagong using the latest available information on seismicity in the region. The latest updated earthquake catalog homogenized in uniform moment magnitude scale was prepared. Seismicity analysis was carried out, and the seismicity parameters for the region were estimated from the frequency magnitude distribution plot. The peak ground acceleration (PGA) and the spectral acceleration at the bedrock for 10% and 2% probability of exceedance within 50 years were evaluated using different source models and attenuation relations in a logic tree framework. The site was characterized based on the soil investigation data from 31 boreholes and amplification factors considering the local geology (SPT-N values) were obtained through ground response analysis. Subsequently, the surface level peak ground acceleration was estimated and depicted in the form of hazard contour maps.

In the present study, coir is used to fabricate geocells and to construct model retaining walls for application in sloppy regions to retain the soil. The performance of coir geocells under dry and wet conditions during rainfall were evaluated by conducting laboratory model tests. The study presents horizontal and vertical deformation against surcharge load for different scenarios of reinforcement using geocells. A comparison was made between the performance of unreinforced slope, high-density polyethylene geocell retaining wall and coir geocell retaining wall to evaluate the potential of coir geocell over synthetic geocell as reinforcement. The roughness and absence of perforations in coir material resisted the movement and failure of the wall for a longer span. The horizontal displacement was more for coir geocell retaining wall compared to wall made of high density polyethylene (HDPE) geocells. This may be due to the interlocking effect in coir HDPE geocell as perforations provide contact between the sand particles. The inexpensive and easily disposable coir can be effectively used as reinforcement in the construction of a retaining wall.

This paper presents the stability analysis of a dike proposed to impound the river flood waters within an estuary near the west coast of south India. The proposed dike will be located within Ashtamudi Lake, the second largest lake in the state of Kerala, India, separating fresh water from brackish water. Constructing a dike at Munro Island portion of Ashtamudi, which is about 9.23 km from Arabian Sea coast, can meet the water demands of the region as well as prevent the sinking of Island during high tide. The river dike is designed to construct artificially as rock filled structures. The stratigraphy in the top 2 m consists of clayey mud underlined by fine to medium sand up to 6 m followed by alternate layers of clay and sand up the investigated depth of 15 m. In this paper, the stability of the dike located in an estuarine environment has been investigated and the factor of safety values have been determined with varying water level conditions and varying properties of the underlying soil. A detailed parametric study using RocScience software is presented, considering all the design conditions. The expected settlement of the dike is estimated considering the soil profile at the location both manually as well as using software Geo5. Both were in good agreement and the maximum possible settlement was found to be less than half a meter.

This study presents an evaluation of liquefaction potential for combined cycle power plant site located in the Chittagong district, Bangladesh, using standard penetration test blow counts (SPT-N values). The peak ground acceleration (PGA) values at a bedrock level were estimated deterministically using both linear and point source models as well as different ground motion prediction equations (GMPEs). The surface level hazard was estimated using amplification factors for the soil conditions present and the response spectrum at the center of the plant site was plotted. The liquefaction potential for the site was arrived at by using the SPT-N values of 33 boreholes in the site and at every 3-meter interval from the ground level to a depth of 30 meters. The results from the LPI contours at successive depths indicate that in the majority of the borehole locations, the soil up to 15 meters depth had a significant hazard of liquefaction. These findings from the present study can prove to be crucial from the structural point of view, for any future construction activities in the area.

The understanding of the systemic risk posed by multi-hazard is becoming a new area of research and adopted by the different global and national frameworks. This chapter summarizes the contents of the book titled geohazard mitigations, which contains thirty-eight chapters. These chapters are divided into three sections namely: multi-hazard assessment, landslide hazard assessment and mitigation, and geotechnical engineering. This chapter also includes basic definitions and introduction to geohazard investigation and management.

This chapter presents the definitions and concepts of disaster risk reduction and its relation to the discipline of civil engineering. It is important to have the infrastructure resilient to disaster. In addition, civil engineering has the potential to offer solutions that can reduce the risk during a disaster. The disaster risk can be reduced by reducing the exposure and vulnerability. The civil engineers can reduce the disaster risk in several ways such as proper land use planning, integrating efficient codal provisions, appropriate design reducing the vulnerability, quality improvement in construction, provision of sea walls, flood protection structures, drainage systems, and earth retention schemes. This book envisages knowledge dissemination on disaster risk reduction primarily focusing on civil engineering perspectives and cross-cutting issues. Research and innovations in civil engineering have the potential to offer solutions toward disaster resilient infrastructures. The vision of this book is in line with the priorities set by UN-SFDRR and UN-SDGs to promote a global culture of risk-awareness and disaster reduction.

A landslide is a life-threatening event causing large infrastructural damages. The major causes for landslides are rainfall, earthquakes, blasting, and other man-made activities. The landslides can happen even without human interference, and hence, it can be classified as a natural process. The population expansion in landslide-prone areas demands a better sustainable method for slope protection and landslide prediction. The main objective of this chapter is to review the previous research studies conducted in the soil slopes using manual instrumentations and the improved data acquisition systems (DAQ) that are used recently. A landslide early warning system (LEWS) is only as strong as the understanding of the phenomenon. The first objective of the development of an early warning system is to find the triggering mechanism of the impending disaster. The three landslide triggering mechanisms are excess rain, seismic activities, and man-made activities. For rainfall-induced landslides, finding the rainfall threshold parameter is one of the difficult tasks. The methods involved in finding this threshold and using it for the development of the LEWS will be discussed in this chapter.

Time–Frequency Analysis (TFA) techniques help to obtain the ideal time and frequency occurrence characteristics of earthquake motion confined in a seismic recorded signal. Time-histories from recording stations in Japan has been adopted in the present analysis, considering a large number of available data. The seismograms were transformed using Gabor transform, a Linear Joint TFA method, to assess their frequency content by generating their Gabor coefficients. Average Gabor coefficients were estimated for recorded seismograms within a magnitude range of 5.5–6.0 and hypocentral distances ranging from 0 to 50 km. The estimated average Gabor coefficients were used to synthesize a generalized acceleration-time history for the specific distance and magnitude ranges using Gabor Expansion, without compromising the frequency content of the waves. Additionally, it is demonstrated that the response spectra of the synthesized signal and the original signal match very well. These response spectra will be valuable for the nonlinear investigation of structures in this region.

This chapter presents basic concepts related to climate change and water security. Further, the chapter introduces the book volume on Climate Change and Water Security that includes various relevant topics for assessment of water quantity and quality in a changing environment, disaster risk, their possible future prognosis, as well as adaptation and protection measures. The focus is primarily on low-income countries such as India, Ethiopia, and Bangladesh, that may be particularly vulnerable to the adverse effects of climate change.

This chapter summarizes the contents of the book volume on resilient infrastructures which discusses various relevant topics such as disaster resilience and infrastructure, risk reduction and structural measures, evidence-based approach for DRR case studies, numerical modeling and constructions methods, prevention methods and safety engineering, and cross-cutting issue in DRR and infrastructure. Basic definitions and information on resilient infrastructure are also included in the chapter.

This chapter summarizes the contents of the book volume on Recent Advances in Earthquake Engineering which discusses various relevant topics such as Seismic ground motion studies, Structural and geotechnical vulnerability assessment, Retrofitting and rehabilitation, Review of building codes, as well as more recent technological introduction of geospatial tools and geographical information systems. Cascading disasters such as fire hazards following an earthquake are also discussed in this volume.

This paper presents the results of model footing tests on sand bed reinforced with HDPE and coir geocells. The infill material influences the performance of geocells. The potential of sand tire crumb (STC) mixture as infill material is evaluated in the study in comparison with pure sand as infill materials. To select the appropriate blend of sand and tire crumb, the shear properties and density properties were analyzed by performing direct shear and density tests. The mix which has shown the highest shear strength and density properties has been selected, and plate load tests were carried to analyze the mechanism and effectiveness of tire crumb as infill material in geocell pockets. From the results, it is clear that the sand tire crumb mix is effective as infill materials, especially for coir geocells. The surface heave was found to reduce significantly with sand tire crumb mix as infill material.

In this paper, the possibility of using naturally available low-cost areca leaf sheaths as an alternative to the commercially available HDPE geocell has been explored by conducting the laboratory m...

This paper presents the suitability of geogrids made from areca leaf sheaths, as soil reinforcement. The performance of areca geogrids was evaluated through the model footing tests and the same has...

It is essential to understand the soil characteristics of the subsurface layers for any engineering construction. In difficult terrains like hilly areas, conventional methods of investigation are expensive and difficult to conduct. It calls for nondestructive testing methods to get reliable estimates of subsurface properties. In the present study, seismic refraction tomography (SRT) technique and multichannel analysis of surface waves (MASW) methods were carried out along five selected profiles in Phuentsholing region of Bhutan Himalaya. The profile length ranges from 37 to 81.5 m, and depth of imaging down to 10 m. While the SRT data imaged the P-wave velocity (Vp) structures, the MASW imaged the shear wave velocity (Vs) structures. The P-wave images provide a fair knowledge of geological layers, while the MASW images provide S-wave velocity structures (Vs). These results are useful to estimate soil parameters, like the density, Poisson’s ratio, Young’s modulus, shear modulus, N-value and the ultimate bearing capacity. The seismic images reveal the presence of sand, sandy clay, gravels and shale layers below the selected sites. Bhutan Himalayas being seismically vulnerable, the obtained results in terms of shear wave velocity were accustomed to categorize the sites as per NEHRP site classes, and a ground response analysis was performed to determine the reliable amplification factors. From the study, it is suggested that the engineering construction is feasible at all the sites except in one site, where an indication of saturated soil is observed which is vulnerable for liquefaction, and ground needs to be improved before construction at that site.

This paper presents a detailed review of past research studies on trenching techniques for vibration isolation. With rapid urbanization and fast-growing infrastructures in developing countries like India, it is very likely for many structures subject to vibrations from earthquakes, traffic movements, or machine vibrations. Though the trench technique for vibration screening is an established technique, there has been a lot of advancements in vibration screening in recent years. This paper presents an overview of the developments in trenching techniques for vibration screening from its inception to the latest advancements. The studies have been categorized into laboratory element/model tests, field tests, and numerical analyses. The review of studies highlights that the open trenches perform better isolation for shallow depths whereas the infilled trenches perform better than open trenches when the normalized depth of trench is deeper.

Present study focuses on developing region-specific New Generation Ground Motion Prediction Models using Artificial intelligence technique for North India purely based on a measured ground motion data from specific region. Simple single hidden layered feed forward multilayer perceptron networks with back-propagation learning algorithm are used. A total of 280 data points of recorded strong motion data from the Kangra and Uttar Pradesh (UP) arrays, made available by the Program for Excellence in Strong Motion Studies (PESMOS), were used to train these networks. The first model predicts Moment Magnitude for a given Hypocentral Distance and Peak Ground Acceleration. The second model predicts Peak Ground Acceleration (PGA) for a given Hypocentral Distance (HPD) and Moment Magnitude (MM). Performance analysis, Uncertainty analysis and analysis of interactive effects have been done to test the reliability of the generated models. Optimization analysis was also performed to predict possible inputs of the models for a given set of outputs. Models have performed reasonably well for the given amount of non-linearity in the data.

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.

This paper presents the seismic hazard analysis of Jaitapur region on the west coast of India, where a nuclear power plant is being planned to locate. A homogenized earthquake catalog in unified moment magnitude scale for the region has been prepared compiling updated data from different agencies. The seismicity parameters were estimated for Jaitapur region, and the hazard evaluation has been performed using different methodologies with different source models and attenuation relations. The deterministic and probabilistic seismic hazard analyses were performed with currently available data and their best possible scientific interpretation by considering alternative models (source models, maximum magnitude, and attenuation relationships). The hazard maps have been produced for horizontal ground motion on the bedrock level using both deterministic and probabilistic methods. The value of Peak Horizontal Acceleration (PHA) for the study region estimated probabilistically for 475 year return period varies from 0.05 to 0.2 g, whereas with deterministic approach, PHA reaches value as high as 0.3 g.