Spatial Analysis of Coastal Vulnerability Indicators Along the Kerala Coast, India

Coastal regions are globally threatened by increasing inundation risks due to climate-induced sea-level rise, intensifying storm surges, and anthropogenic pressures. Understanding the spatial interplay of the physical and socioeconomic drivers of vulnerability is critical for effective risk reduction. This study conducts a high-resolution spatial analysis of three vulnerability components along the Kerala coast, India; coastal characteristics, coastal forces, and socioeconomic components. Coastal characteristics include geomorphology, elevation, landward and seaward slopes, shoreline change rates, and continental shelf width. The coastal forces component comprises tide, significant wave height, sea-level anomalies, and extreme events. The socioeconomic component evaluates land use/land cover, population density, road networks, tourist hotspots, and coastal protection structures.

The spatial distribution of coastal characteristics indicates that coastal plains and floodplains, covering nearly 20 percent of the study area, are dominated by low elevation and gentle slopes that favour prolonged water retention and increased exposure to coastal flooding. Areas below 10 m elevation exhibit limited natural buffering against tidal inundation and storm surge impacts. Gentle landward slopes and flatter nearshore bathymetry promote inland penetration of wave energy. Persistent shoreline erosion and a narrow continental shelf, which enhances nearshore wave energy concentration. Coastal forcing components further modulate flood vulnerability, contributing to elevated coastal water levels and these conditions spatially coincide with zones historically impacted by catastrophic events like the 2004 Indian Ocean tsunami. Socioeconomic vulnerability is concentrated in urbanized coastal stretches, where built-up areas constitute ~65% of high-vulnerability zones, supporting population densities exceeding 5000 persons/km². Critical infrastructure and tourist hubs are predominantly located within this high-exposure corridor, increasing potential impacts. Existing hard-engineered defenses are spatially limited and insufficient to mitigate the compound risk.

The spatial characterization of vulnerability-driving components provides a robust foundation for integrated coastal vulnerability assessments related to coastal flooding driven by sea-level rise, storm surges, and wave action, and supports evidence-based coastal planning and climate adaptation strategies along the Kerala coast.