Using terrain-derived indices and environmental components to examine the spatial context of undocumented immigrant mortality along the USA–MEX border

Environmental exposure is the leading identifiable cause of mortality for undocumented immigrants the Tucson Sector of the USA–Mexico border. This paper investigates the role of environmental components in predicting immigrant mortality sites between 1981 and 2023 (n = 3427). Using a high-resolution terrain surface and geospatial techniques to derive a suite of environmental metrics for a panel linear modeling framework, we found that potential evapotranspiration was the strongest predictor of mortality location. Since 2011, for every 1 mm/day increase in potential evapotranspiration, the probability of predicting a mortality site was 14.85 % higher than a random location. A 1-hr increase in direct solar radiation decreased the chance of predicting a mortality site by 2 % and slope followed the same trend at 1.094 % decrease per degree. Overall, mortality sites were situated in areas that were drier (p < 0.001), received direct solar radiation for less time (p < 0.001), were flatter (p < 0.001), and were nearer the USA–MEX border (p < 0.001) than random. These findings suggest that exposure to severe aridity for prolonged periods, rather than time spent in direct solar radiation, most influences where mortality is likely to occur.