Mapping and evaluating spatiotemporal patterns of urban expansion in global earthquake-affected areas: a nighttime light remote sensing perspective

Amidst the backdrop of frequent global earthquakes, assessing the spatiotemporal dynamics of urban expansion in earthquake-affected areas is imperative for sustainable development insights. The current analyses, however, are primarily focused on administrative units or some specific natural units. Here, we quantified spatiotemporal patterns of urban expansion from 2000 to 2020 in global earthquake-affected areas globally. Specifically, we delineated such areas using data from earthquakes of magnitude 5.5 and above since 1965. Then, employing nighttime light remote sensing data, we extracted urban entities and systematically evaluated the spatiotemporal patterns of urban expansion in earthquake-affected areas. The findings indicate a phase-based differential growth in urban expansion in earthquake-affected areas from 2000 to 2020. The average deceleration factor for urban areas in earthquake-affected areas over the past 20 years is 128.67%. Urban expansion in earthquake-affected areas is growing at a rapid pace, except for Europe and North America. In addition, 66.7% of urban expansion in global earthquake-affected areas presents low-density sprawl and solitary edge expansion trends, potentially affecting population density and land use efficiency. This study offers the most exhaustive analysis of urban expansion in earthquake-affected areas in recent decades and calls for administration beyond administrative boundaries to some extent.