Goal of this study is to find the most vulnerable areas to tsunami impacts on groundwater resources on a global scale. To achieve this a global database is build and vulnerability to tsunami effects is assessed on various levels (topographical,tsunami risk and socio-economical). After finding the most vulnerable areas worldwide, statistics of precipitation rate and soil types are extracted in form of histograms. These values are then used in computer modeling to evaluate the severity of salt water intrusion in coastal aquifers due to tsunami inundation.
Vulnerability assessement of coastal aquifers to tsunami induced salt water intrusion on a global scale
Major tsunami events struck the coasts around the world in last decade with fatal consequences in terms of human casualties and material damage. While effects of a tsunami are clearly visible and well documented on the surface, little is known about the impacts on groundwater resources in the inundated areas. This study focuses on finding the most vulnerable areas to groundwater salinization caused by tsunami inundation. First, a topographical vulnerability index is calculated using information from the SRTM90m dataset (DEM of the world). Thereafter, a global tsunami hazard study by (Løvholt et al.) helps to choose only areas with potential high risk of tsunami. At last, regions with income below poverty line (1$/day per capita) are picked as the most vulnerable, due to no availability of alternative freshwater resources. Once these areas are selected, a search for parameter statistics such as soil type and precipitation is performed using a method of raster masking (overlay). Parameter statistics help to create ranges of values which are then used during a modeling process of salinization of fresh groundwater aquifers due to tsunami inundation. A conceptual 2D model is created with total length of 5km and depth of 50m, each model simulation has a unique combination of parameter values. The severity of salinization is quantified as time necessary for a specific area to restore a freshwater concentration in more than 95% of its extent. The method proposed in this study gives a lot of opportunities for vulnerability assessment to different hazards on a global scale. Selection of areas can be repeated with altered criteria to find areas with different characteristics.