This thesis reports a rock slope hazard investigation located in the Central Andes of Chile, where two significant rock mass wasting events were recognized. Dating using cosmogenic nuclide for ³⁶Cl showed that the deposits were post-glacial in age, corresponding to the Upper Pleistocene Portillo Rock Avalanche (PRA) and a Holocene rock slump and rockslide. The pre-historic landslide deposits underlie both a key transportation route between Chile and Argentina and an important ski resort. The purpose of this research was to investigate the likely failure mechanism and characterise the runout path and volume of the PRA. The insights gained on the back analysis of the slope were used in later stages to assess the hazard potential of a recurring major rockslide. The distinct element code UDEC was used to evaluate the failure mechanism. Elasto-plastic modelling results showed that sliding and shearing along the bedding planes together with brittle fracturing and shearing through the toe of the slope likely had occurred. Runout simulations were carried out using DAN3D. Combinations of rheologies were tested and ranked based on their ability to represent the current distribution of the debris by means of pre-failure topography reconstruction and volume estimates of the deposits. Results showed that the best basal rheological combination for the PRA was frictional during the rockslide and Voellmy when entrainment became important. In contrast, a constant frictional basal rheology best represented the Holocene rock slump. The performance of the present-day state of the slope was tested under different scenarios. Under static condition the slope proved to be stable indicating a stabilized geometrical profile with time. Also, the slope proved to be stable under increased pore water pressures at its toe. Finally the modelled slope was subjected to a seismic load (M=7.8) and its crest failed due to an outward rotation of blocks, probably aided by topographic amplification. The runout simulations showed that the leading edge of the flow could override part of the International Santiago-Mendoza Corridor with no direct impact to the Portillo Ski Resort. Overall, though, under this highly unlikely dynamic condition for the site, the hazard level is very low.

White Island and Ruapehu are currently the most active volcanoes in New Zealand. During non-eruptive periods, intense quiescent degassing through fumaroles can occur. The current project studies the quiescent degassing plumes, including aerosol sampling on White Island and dispersion modelling of SO₂ and PM₁₀ from White Island and Ruapehu volcanoes. Aerosol sampling from fumaroles at the crater floor on White Island volcano was carried out on 9 February and 6 April 2005. The exposed filters were analysed for various anions and cations and the particle mass concentration and molar concentration determined. Major elemental constituents were sodium and chlorine (Na⁺: 413 µg m⁻³, Cl⁻: 1520 µg m⁻³), which show best correlation at both sampling sessions. Other ions detected, with little correlation, are Ca²⁺, PO₄³⁻ and to a certain extent Mg²⁺. Other constituents found, which cannot correlate explicitly to other ions, are K⁺, NH₄⁺, NO₃⁻, and SO₄²⁻. SEM study of one exposed filter was performed and mainly NaCl particles could be distinguished due to their well-defined cubic shape. The Air Pollution Model (TAPM) was used for dispersion modelling of SO₂ (models 1-4) and PM₁₀ (models 5 and 6) from White Island and Ruapehu volcanoes. Annual modelling was performed using different parameters of emission rate, exit temperature and exit velocity. The resulting plume dispersions show relatively low concentrations at ground level ≤10 m), particularly for the models of PM₁₀ dispersion. TAPM calculated the highest SO₂ ground level concentrations with model 4, where the NES values of 350 and 570 µg m⁻³ were exceeded several times. The data was then used for detailed hazard assessment of urban population in the North Island. The meteorological data from annual modelling was used for model evaluation and compared with observation data from different weather stations by statistical calculations. Overall, TAPM performed well with most good and very good results. To evaluate SO₂ dispersion modelling, airborne plume measurements were carried out on 22 November 2006 by plume traverses at 3, 10 and 20 km. Although there is some variation, the calculated correlation coefficients indicate good model results for two plume traverses at 3 and 20 km and one plume traverse at 10 km. The meteorological data was also used for model evaluation, and the results indicate good model performance. TAPM is therefore suggested for future studies when more observation data are available to verify the calculated model data.

Debris-flows pose serious hazards to communities in mountainous regions of the world and are often responsible for loss of life and damages to infrastructure. Characterised by high flow velocity, large impact forces and long runout, debris-flows have potential discharges several times greater than clear water flood discharges and possess much greater erosive and destructive potential. In combination with poor temporal predictability, they present a significant hazard to settlements, transport routes and other infrastructure located at the drainage points (fan-heads) of watersheds. Thus, it is important that areas vulnerable to debris-flows are identified in order to aid decisions on appropriate land-uses for alluvial fans. This research has developed and tested a new GIS-based procedure for identifying areas prone to debris-flow hazards in the Coromandel/Kaimai region, North Island, New Zealand. The procedure was developed using ESRI Arc View software, utilising the NZ 25 x 25 m DEM as the primary input. When run, it enabled watersheds and their associated morphometric parameters to be derived for selected streams in the study area. Two specific parameters, Melton ratio (R) and watershed length were then correlated against field evidence for debris-flows, debris-floods and fluvial processes at stream watershed locations in the study area. Overall, strong relationships were observed to exist between the evidence observed for these phenomena and the parameters, thus confirming the utility of the GIS procedure for the preliminary identification of hydrogeomorphic hazards such as debris-flow in the Coromandel/Kaimai region study area. In consideration of the results, the procedure could prove a useful tool for regional councils and CDEM groups in regional debris-flow hazard assessment for the identification of existing developments at risk of debris-flow disaster. Furthermore, the procedure could be used to provide justification for subsequent, more intensive local investigations to fully quantify the risk to people and property at stream fan and watershed locations in such areas.

The Canterbury Region is susceptible to a variety of natural hazards, including earthquakes, landslides and climate hazards. Increasing population and tourism within the region is driving development pressures and as more and more development occurs, the risk from natural hazards increases. In order to avoid development occurring in unacceptably vulnerable locations, natural hazard assessments are required. This study is a reconnaissance natural hazard assessment of Lakes Lyndon, Coleridge and Tekapo. There is restricted potential for development at Lake Lyndon, because the land surrounding the lake is owned by the Crown and has a number of development restrictions. However, there is the potential for conservation or recreation-linked development to occur. There is more potential for development at Lake Coleridge. Most of the land surrounding the lake is privately owned and has less development restrictions. The majority of land surrounding Lake Tekapo is divided into Crown-owned pastoral leases, which are protected from development, such as subdivision. However, there are substantial areas around the lake, which are privately owned and, therefore, have potential for development. Earthquake, landslide and climate hazards are the main natural hazards threatening Lakes Lyndon, Coleridge and Tekapo. The lakes are situated in a zone of active earth deformation in which large and relatively frequent earthquakes are produced. A large number of active faults lie within 15 km of each lake, which are capable of producing M7 or larger earthquakes. Ground shaking, liquefaction, landslides, tsunami and seiches are among the consequences of earthquakes, all of which have the potential to cause severe damage to lives, lifelines and infrastructure. Landslides are also common in the landscape surrounding the lakes. The majority of slopes surrounding the lakes are at significant risk from earthquake-induced failure under moderate to strong earthquake shaking. This level of shaking is expected to occur in any 50 year period around Lakes Lyndon and Coleridge, and in any 150 year period around Lake Tekapo. Injuries, fatalities and property damage can occur directly from landslide impact or from indirect effects such as flooding from landslide-generated tsunami or from landslide dam outbreaks. Lakes Lyndon, Coleridge and Tekapo are also susceptible to climate hazards, such as high winds, drought, heavy snowfall and heavy rainfall, which can lead to landslides and flooding. Future climate change due to global warming is most likely going to affect patterns of frequency and magnitudes of extreme weather events, leading to an increase in climate hazards. Before development is permitted around the lakes, it is essential that each of these hazards is considered so that unacceptably vulnerable areas can be avoided.

The focus of this thesis is the regulatory aspects of environmental hazard and risk assessment of chemicals, with a particular emphasis on whether current regulatory requirements are sufficient for assessing the risks chemicals pose to the environment. Since the way that chemicals are currently regulated on a global, regional or national level is complex and challenging, it is not surprising that there are faults with the current system. Legislations and regulations, such as the European regulation on Registration, Evaluation, Authorisation and restrictions of Chemicals (REACH), specifically indicates that unnecessary testing should be avoided wherever possible. However, this has not been the case for all hazard evaluations and some substances may have been assessed unnecessarily, or incorrectly resulting in significant underestimation of the potential effects to the environment. The aim of this research was to identify the major pitfalls and flaws with how environmental risk assessments are being performed, and to find a more harmonious approach to properly ensure that chemicals are regulated more appropriately. Within this thesis, there are examples of ecotoxicity studies for substances that should have little or minimal environmental consequences but which have been required for regulatory reasons. Such an example highlighted in this thesis is the artificial sweetener sucralose or silica fume. Conversely, other substances which are likely to have severe adverse environmental impacts could have been authorised for use inappropriately without the additional research that was carried out. Examples of potentially harmful chemicals not being regulated sufficiently, detailed in this thesis, include benzoylurea pesticides, used in aquaculture, and novel antifoulant substances such as thiophenones used in industrial processes. The papers in this thesis indicate that there is a large disparity between how some substances are being regulated. In order to improve the current situation and to aid environmental risk assessors and regulatory authorities, integrated strategies have been proposed incorporating all available data to collectively inform on for example the bioaccumulative properties of a substance. In addition, recommendations for improving the risk assessment processes are discussed with the aim of better regulating chemicals and harmonizing future environmental risk assessments.

This thesis reports a rock slope hazard investigation located in the Central Andes of Chile, where two significant rock mass wasting events were recognized. Dating using cosmogenic nuclide for ³⁶Cl showed that the deposits were post-glacial in age, corresponding to the Upper Pleistocene Portillo Rock Avalanche (PRA) and a Holocene rock slump and rockslide. The pre-historic landslide deposits underlie both a key transportation route between Chile and Argentina and an important ski resort. The purpose of this research was to investigate the likely failure mechanism and characterise the runout path and volume of the PRA. The insights gained on the back analysis of the slope were used in later stages to assess the hazard potential of a recurring major rockslide. The distinct element code UDEC was used to evaluate the failure mechanism. Elasto-plastic modelling results showed that sliding and shearing along the bedding planes together with brittle fracturing and shearing through the toe of the slope likely had occurred. Runout simulations were carried out using DAN3D. Combinations of rheologies were tested and ranked based on their ability to represent the current distribution of the debris by means of pre-failure topography reconstruction and volume estimates of the deposits. Results showed that the best basal rheological combination for the PRA was frictional during the rockslide and Voellmy when entrainment became important. In contrast, a constant frictional basal rheology best represented the Holocene rock slump. The performance of the present-day state of the slope was tested under different scenarios. Under static condition the slope proved to be stable indicating a stabilized geometrical profile with time. Also, the slope proved to be stable under increased pore water pressures at its toe. Finally the modelled slope was subjected to a seismic load (M=7.8) and its crest failed due to an outward rotation of blocks, probably aided by topographic amplification. The runout simulations showed that the leading edge of the flow could override part of the International Santiago-Mendoza Corridor with no direct impact to the Portillo Ski Resort. Overall, though, under this highly unlikely dynamic condition for the site, the hazard level is very low. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

Reliable and robust methods of extreme value based hurricane surge prediction, such as the Joint Probability Method (JPM), are critical in the coastal engineering profession. The JPM has become the preferred surge hazard assessment method in the United States; however, it has a high computational cost: one location can require hundreds of simulated storms, and more than ten thousand computational hours to complete. Optimal sampling methods that use physics based surge response functions (SRFs), can reduce the required number of simulations. This study extends the development of SRFs to bay interior locations at Panama City, Florida. Mean SRF root-mean-square (RMS) errors for open coast and bay interior locations were 0.34 m and 0.37 m, respectively; comparable to expected ADCIRC model errors (~0.3 m—0.5 m). Average uncertainty increases from open coast and bay SRFs were 10% and 12%, respectively. Long-term climate trends, such as rising sea levels, introduce nonstationarity into the simulated and historical surge datasets. A common approach to estimating total flood elevations is to take the sum of projected sea-level rise (SLR) and present day surge (static approach); however, this does not account for dynamic SLR effects on surge generation. This study demonstrates that SLR has a significant dynamic effect on surge in the Panama City area, and that total flood elevations, with respect to changes in SLR, are poorly characterized as static increases. A simple adjustment relating total flood elevation to present day conditions is proposed. Uncertainty contributions from these SLR adjustments are shown to be reasonable for surge hazard assessments. / Master of Science

A probabilistic framework is developed to assess the structural reliability of offshore wind turbines. Probabilistic models are developed to predict the deformation, shear force and bending moment demands on the support structure of wind turbines. The proposed probabilistic models are developed starting from a commonly accepted deterministic model and by adding correction terms and model errors to capture respectively, the inherent bias and the uncertainty in developed models. A Bayesian approach is then used to assess the model parameters incorporating the information from virtual experiment data. The database of virtual experiments is generated using detailed three-dimensional finite element analyses of a suite of typical offshore wind turbines. The finite element analyses properly account for the nonlinear soil-structure interaction. Separate probabilistic demand models are developed for three operational/load conditions including: (1) operating under day-to-day wind and wave loading; (2) operating throughout earthquake in presence of day-to-day loads; and (3) parked under extreme wind speeds and earthquake ground motions. The proposed approach gives special attention to the treatment of both aleatory and epistemic uncertainties in predicting the demands on the support structure of wind turbines. The developed demand models are then used to assess the reliability of the support structure of wind turbines based on the proposed damage states for typical wind turbines and their corresponding performance levels. A multi-hazard fragility surface of a given wind turbine support structure as well as the seismic and wind hazards at a specific site location are incorporated into a probabilistic framework to estimate the annual probability of failure of the support structure. Finally, a framework is proposed to investigate the performance of offshore wind turbines operating under day-to-day loads based on their availability for power production. To this end, probabilistic models are proposed to predict the mean and standard deviation of drift response of the tower. The results are used in a random vibration based framework to assess the fragility as the probability of exceeding certain drift thresholds given specific levels of wind speed.

Past earthquakes have demonstrated that Indian sub-continent is highly vulnerable to earthquake hazards. It has been estimated that about 59 percent of the land area of the Indian subcontinent has potential risk from moderate to severe earthquakes (NDMA, 2010). Major earthquakes in the last 20 years such as Khillari (30th September 1993), Jabalpur (22nd May 1997), Chamoli (29th March 1999) and Bhuj (26th January 2001) earthquakes have resulted in more than 23,000 deaths and extensive damage to infrastructure (NDMA, 2010). Although it is well known that the major earthquake hazard prone areas in India are the Himalayan region (inter-plate zone) and the north-east region, (subduction zone) the seismicity of Peninsular India cannot be underestimated. Many studies (Seeber et al., 1999; Rao, 2000; Gangrade & Arora, 2000) have proved that the seismicity of Peninsular India is significantly high and may lead to earthquakes of sizeable magnitude. This necessitates a seismic zonation for the country, as well as various regions in it. Seismic zonation is the first step towards an effective earthquake risk mitigation study. Seismic zonation is a process in which a large region is demarcated into small zones based on the levels of earthquake hazard. Seismic zonation is generally carried out at three different levels based on the aerial extent of the region, importance of site and the population. They are micro-level, meso-level and macro-level. The macro-level zonation is generally carried out for large landmass such as a state or a country. The earthquake hazard parameters used for macro-level zoning are generally evaluated with less reliability. The typical example of a macro-level zonation is the seismic zonation map of India prepared by BIS-1893 (2002), where the entire India is demarcated into four seismic zones based on past seismicity and tectonic conditions. Generally the macro-level seismic zonation is carried out based on peak horizontal acceleration (PHA) estimated at bedrock level without giving emphasis on the local soil conditions. Seismic zonation at the meso-level is carried out for cities and urban centers with a population greater than 5,00,000. The earthquake hazard parameters, for the meso-level zonation are evaluated with greater degree of reliability, compared to the macro-level zoning. The micro-level zonation is carried out for sites which host critical installations such as nuclear power plants (NPPs). As the NPPs are considered as very sensitive structures, the earthquake parameters, for the micro-level zonation of the NPP sites are estimated with a highest degree of reliability. The local soil conditions and site effects are properly counted for carrying out the micro as well as the meso-level zonation. Several researchers have carried out meso-level zonation considering effects of all major earthquake hazards such as PHA, site amplification, liquefaction (Mohanty et al., 2007; Nath et al., 2008; Sitharam & Anbazhagan, 2008 etc.) Even though the above definitions and descriptions are available for various levels of zonation, the key issue lies in the adoption of the suitable one for a given region. There are only a few guidelines available regarding the use of a particular level of zonation for a given study area. Based on the recommendation of the disaster management authority, the government of India has initiated the seismic zonation of all major cities in India. As it is evident that large resources are required in order to carry out seismic site characterization and site effect estimation, both the micro and meso-level zonations cannot be carried out for all these cities. Hence there is a need to propose appropriate guidelines to define the suitability of each level zonation for various re-gions in the country. Moreover there are many methodologies available for site characterization and estimation of site effects such as site amplification and liquefaction. The appropriateness of these methodologies for various levels of seismic zonations also needs to be assessed in order to optimize use of resources for seismic zonation. Hence in the present study, appropriate techniques for site characterization and earthquake hazard estimation for regions at different scale levels were determined. Using the appropriate techniques, the seismic zonation was carried out both at the micro and macro-level, incorporating all major earthquake hazards. The state of Karnataka and the Kalpakkam NPP site were chosen for the macro and micro−level seismic zonation in this study. Kalpakkam NPP site is situated in Tamil Nadu, India, 70 kilometres south of Chennai city. The NPP site covers an area of 3000 acres. The site is situated along the Eastern coastal belt of India known as Coromandel coast with Bay of Bengal on the east side. The NPP site host major facilities such as Indira Gandhi Centre for Atomic Research (IGCAR), Madras Atomic Power Station (MAPS), Fast Reactor Fuel Reprocessing (FRFC) Plant, Fast Breeder Test Reactor (FBTR), Prototype Fast Breeder Reactor (PFBR) etc. The state Karnataka lies in the southern part of India, covering an area of 1,91,791 km2, thus approximately constituting 5.83% of the total geographical area of India. Both the study areas lie in the Indian Peninsular which is identified as one of the most prominent and largest Precambrian shield region of the world. The first and foremost step towards the seismic zonation is to prepare a homogenised earthquake catalogue. All the earthquake events within 300 km radius from the boundary of two study areas were collected from various national and international agencies. The earthquake events thus obtained were found to be in different magnitude scales and hence all these events were converted to the moment magnitude scale. A declustering procedure was applied to the earthquake catalogue of the two study area in order to remove aftershocks, foreshocks and dependent events. The completeness analysis was carried out and the seismicity parameters for the two study areas were evaluated based on the complete part of earthquake catalogues. The next major step toward the estimation of earthquake hazard and seismic zonation is the identification and mapping of the earthquake sources. Three source models, mainly; 1) linear source model, 2) point source model and 3) areal source model were used in the present study for characterizing earthquake sources in the two study areas. All the linear sources (faults and lineaments) within 300 km radius from the boundary of two study areas were identified and mapped from SEISAT (2000). In addition to SEISAT (2000), some lineaments were also mapped from the works of Ganesha Raj & Nijagunappa (2004). These lineaments and faults were mapped and georeferenced in a GIS platform on which earthquake events were then super-imposed to give seismotectonic atlas. Seismotectonic atlas was prepared for both the study areas. The point source model (Costa et al. 1993; Panza et al. 1999) and areal source model (Frankel, 1995) were also adopted in this work. Deterministic and probabilistic seismic hazard analysis was found to be appropriated for micro, meso and macro-level zonations. Hence in the present study, the seismic hazard at bedrock level, both at the micro and macro-level were evaluated using the deterministic as well as the probabilistic methodologies. In order to address the epistemic uncertainties in source models and attenuation relations, a logic tree methodology was incorporated with the deterministic and probabilistic approaches. As the deterministic seismic hazard analysis (DSHA) considers only the critical scenario, knowing the maximum magnitude that can occur at a source and the shortest distance between that source and the site and the peak horizontal acceleration (PHA) at that site is estimated using the frequency dependent attenuation relation. Both for the micro as well as the macro-level, the DSHA was carried out, considering grid sizes of 0.001◦ × 0.001◦ and 0.05◦ × 0.05◦respectively. A MATLAB program was developed to evaluate PHA at the center of each of these grid points. The epistemic uncertainties in source models and attenuation relations have been addressed using a logic tree approach (Bommer et al., 2005). A typical logic tree consists of a series of nodes to which several models with different weightages are assigned. Allotment of these weightages to different branch depends upon the degree of uncertainties in the model, and its accuracy. However the sum of all weightages of different branches at a particular node must be unity. Two types of seismic sources are employed in DSHA and they are linear and smoothed point sources. Since both the types of sources were of equal importance, equal weightages were assigned to each of them. The focal depth in the present study was taken as 15 km. The attenuation properties of the region were modelled using three attenuation relations, Viz. Campbell & Bozorgnia (2003), Atkinson & Boore (2006) and Raghu Kanth & Iyengar (2007). The attenuation relation proposed by Raghu Kanth & Iyengar (2007) was given higher weightage of 0.4 since it was devel-oped for the Indian peninsular region. The attenuation relations by Atkinson & Boore (2006) and Campbell & Bozorgnia (2003) which were developed for Eastern North American shield region, shared equal weightages of 0.3. Maps showing spatial variation of PHA value at bedrock level, for both micro and macro-level are presented. Response spectra at the rock level for important location in the two study areas were evaluated for 8 different periods of oscillations, and the results are presented in this thesis. Probabilistic seismic hazard analysis (PSHA) incorporating logic tree approach was per-formed for both micro as well as macro-level considering similar grid sizes as in DSHA. Two types of seismic sources considered in the PSHA are linear sources and smoothed gridded areal sources (Frankel, 1995) with equal weightage distribution in the logic tree structure. Smoothed gridded areal sources can also account the scattered earthquake events. The hypocentral distance was calculated by considering a focal depth of 15 km, as in the case of DSHA method. A MAT-LAB program was developed for PSHA. The same attenuation relations employed in DSHA were used in PSHA as well with the same weightage allotment in logic tree structure. Considering all major uncertainties, a uniform hazard response spectrum (UHRS), showing the variation of PHA values with the mean annual rate of exceedance (MARE), was evaluated for each grid point. From the uniform hazard response spectrum, the PHA corresponding to any return period can be evaluated. Maps showing the spatial variation of PHA value at bedrock level, corresponding to 475 year and 2500 year return periods for both micro and macro-level are presented. Response spectra at the rock level for important location in two study areas were evaluated for eight different periods of oscillations, and the results are presented in this thesis. In order to assess various earthquake hazards like ground motion amplification and soil liquefaction, a thorough understanding of geotechnical properties of the top overburden soil mass is essential. As these earthquake hazards strongly depend on the geotechnical properties of the soil, site characterization based on these properties will provide a better picture of these hazards. In the present study, seismic site characterization was carried both at the micro and macro-level using average shear wave velocity for top 30 m overburden (Vs30). At the micro-level, the shear wave velocity profile at major locations was evaluated using multichannel analysis of surface waves (MASW) tests. MASW is an indirect geophysical method used in geotechnical investigations and near surface soil characterization based on the dispersion characteristics of surface waves (Park et al., 1999). The MASW test setup consists of 24-channel geophones of 4.5 Hz capacity. A 40 kg propelled energy generator (PEG) was used for generating surface wave. Based on the recordings of geophones, the dispersion characteristics of surface waves were evaluated in terms of a dispersion curve. The shear wave velocity (Vs) profile at a particular location was determined by performing inversion analysis (Xia et al., 1999). After the evaluation of V s profile at all major locations, the site characterization at the micro-level was carried out as per NEHRP (BSSC, 2003) and IBC (2009) recommendations. Maps showing the spatial distribution of various site classes at the micro-level are presented in this thesis. Standard penetration tests were also carried out in the site as part of subsurface investigation and in this study a new correlation between V s and corrected SPT-N values was also developed. Apart from carrying out site characterization, low strain soil stiffness profile was evaluated based on SPT and MASW data. In this work, seismic site characterization at the macro-level was also carried out. As it is not physically and economically viable to carry out geotechnical and geophysical testing for such a large area, like the Karnataka state, the seismic site characterization was carried out based on topographic slope maps. Wald & Allen (2007) has reported that the topographic slope is a perfect indicator of site conditions. Based on the correlation studies carried out for different regions, Wald & Allen (2007) has proposed slope ranges corresponding to each site class. In this study, the topographic map for the entire state of Karnataka was derived from ASTER Global Digital Elevation Model GDEM. This thesis also presents a comparison study between the Vs30map generated from topographic slope data and Vs30map developed using geophysical field tests, for Bangalore and Chennai. Based on this study, it is concluded that topographic slopes can be used for developing Vs30maps for meso and macro-level with reasonable accuracy. The topographic map for macro-level was generated at a grid size of 0.05◦ × 0.05◦. Based on the value of slope at a particular grid point, the Vs30for that grid point was assigned as per Wald & Allen (2007). A similar procedure was repeated for all the grid points. Spatial variation of various seismic site classes for the macro-level has been presented in this work. The site amplification hazard was estimated for both micro and the macro-level. The assessment of site amplification is very important for shallow founded structures and other geotechnical structures like retaining walls and dams, floating piles and underground structures as the possible earthquake damages are mostly due to extensive shaking. The site amplification hazard at the micro-level was estimated using 1D equivalent linear ground response analyses. The earthquake motion required for carrying out ground response analysis was simulated from a target response spectrum. 1D equivalent linear analyses were performed using SHAKE 2000 software. Spatial variations of surface level PHA values, site amplification, predominant frequency throughout the study area are presented in this work. As it is not physically viable to assess site amplification hazard at the macro-level using the 1D ground response analysis, the surface level PHA value for the entire state of Karnataka was estimated using a non-linear site amplification technique pro-posed by Raghu Kanth & Iyengar (2007). Based on the site class in which particular grid belongs and bedrock level PHA value, the amplification for that grid point was evaluated using regression equations developed by Raghu Kanth & Iyengar (2007). The liquefaction hazard both at the micro and macro-level was evaluated and included in this thesis. The micro-level liquefaction hazard was estimated in terms of liquefaction potential index (LPI) based on SPTN values (Iwasaki et al., 1982). As the LPI was evaluated by integrating the factor of safety against liquefaction (FSL) at all depths, it can effectively represent the liquefaction susceptibility of the soil column. LPI at the micro-level was evaluated by both deterministic as well as the probabilistic approaches. In the deterministic approach, the FSLat a particular depth was evaluated as the ratio of the cyclic resistance of the soil layer to the cyclic stress induced by earth-quake motion. The cyclic stress was estimated as per Seed & Idriss (1971), while the cyclic soil resistance was characterised from the corrected SPT-N values as proposed by Idriss & Boulanger (2006). However in the probabilistic method, the mean annual rate of exceedance (MARE) of factor of safety against liquefaction at different depth was estimated using SPT field test data by considering all uncertainties. From the MARE curve, the FS L for 475 year and 2500 year return period were evaluated. Once FS L at different depth were evaluated, the LPI for the borehole is calculated by integrating FS L for all depths. The liquefaction hazard at the macro-level was estimated in terms of SPT and CPT values required to prevent liquefaction at 3 m depth, using a probabilistic approach. The probabilistic approach accounts the contribution of several magnitudes acceleration scenarios on the liquefaction potential at a given site. Based on the methodology proposed by Kramer & Mayfield (2007), SPT and CPT values required to resist liquefaction corresponding to return periods of 475 years and 2500 years were evaluated at the macro-level. It has been observed that the spatial distribution of intensity of each these hazard in a region is distinct from the other due to the predominant influence of local geological conditions rather than the source characteristics of the earthquake. Hence it’ll be difficult to assess risk and vulnerability of a region when these hazards are treated separately. Thus, all major earthquake hazards are to be integrated to an index number, which effectively represents the combined effect of all hazards. In the present study, all major earthquake hazards were integrated to a hazard index value, both at the micro as well as macro-level using the Analytical Hierarchy Process (AHP) proposed by Saaty (1980). Both micro and macro-level seismic zonation was performed based on the spatial distribution of hazard index value. This thesis also presents the assessment of earthquake induced landslides at the macro-level in the appendix. Landslide hazards are a major natural disaster that affects most of the hilly regions around the world. This is a first attempt of it kind to evaluate seismically induced landslide hazard at the macro-level in a quantitative manner. Landslide hazard was assessed based on Newmark’s method (Newmark, 1965). The Newmark’s model considers the slope at the verge of failure and is modelled as a rigid block sliding along an incline plane under the influence of a threshold acceleration. The value of threshold acceleration depends upon the static factor of safety and slope angle. At the macro-level, the slope map for the entire state of Karnataka was derived from ASTER GDEM, considering a grid size of 50 m × 50 m. The earthquake motion which induces driving force on the slope to destabilize it was evaluated for each grid point with slope value 10 degree and above using DSHA. Knowing the slope value and peak horizontal acceleration (PHA) at a grid point, the seismic landslide hazard in terms of static factor of safety required to resist landslide was evaluated using Newmark’s method. This procedure is repeated for all grid points, having slope value 10 degree and above.

Produced since the 1950’s, per- and polyfluoroalkyl (PFASs) substances are persistent, bioaccumulative and toxic compounds that are ubiquitous in the environment. Being proteinophilic with a tendency to partition to protein-rich tissues, PFASs have been found in human serum worldwide and in wildlife with a predominance of long-chain perfluoroalkyl carboxilic acids (C7-C14 PFCAs) and perfluoroalkyl sulfonic acids (C6-C9 PFSAs). Due to rising concern regarding their hazardous properties, several regulatory actions and voluntary industrial phase-outs have been conducted since early 2000s, shifting the production towards other fluorinated alternatives. This thesis explores the human exposure to long-chain PFASs and their alternatives using different modelling methods and aims to 1) link comprehensively the past and current industrial production with the human body burden and 2) assess the potential hazardous properties of legacy PFASs replacements, on which information is very limited. In Paper I, the historical daily intakes in Australia and USA were reconstructed from cross-sectional biomonitoring data of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA) andperfluorohexanesulfonic acid (PFHxS). The results indicate that humans experienced similar exposure levels and trends to PFOS and PFOA in both regions, suggesting a common historical exposure possibly dominated by consumer products. The model could not be fitted to PFHxS concentration in serum. In Paper II, the relative contribution of indirect (i.e. subsequent metabolism of precursors into legacy PFASs) versus direct exposure was evaluated on occupationally exposed ski wax technicians. The indirect exposure contributed by up to 45% to the total body burden of PFOA. In Paper III, the physicochemical properties, the persistence and the long-range transport of fluorinated alternatives were predicted using different in silico tools. Findings suggest that fluorinated alternatives are likely similar to their predecessors, in terms of physicochemical properties and environmental fate. Finally, Paper IV compares the toxic potency of PFOS, PFOA and their alternatives as a function of external and internal dose. While alternatives are less potent than their predecessors when considering the administered dose, they become similarly potent when the assessment is based on levels in the target tissue. This thesis demonstrates that pharmacokinetic models are effective tools to comprehensively reconnect the body burden to the exposure of phased-out chemicals. More importantly, the studies on fluorinated alternatives raise the necessity to provide more information and data on the potential hazard of these novel and emerging products. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 4: Manuscript.</p>