High-resolution 3D geological modelling and subsurface architecture of the Valencia urban area (Spain): Insights into urban complexity

The lack of detailed information on Valencia’s subsurface configuration poses significant challenges for civil engineering and urban planning projects. To date， most studies have focused on geotechnical aspects or shallow sedimentology， providing only a limited understanding of the horizontal and lateral variability of sedimentary facies characteristic of alluvial environments.
This study presents a high-resolution model of the first 50 m of the Holocene subsurface in central Valencia， providing new insights into its geological architecture and shallow aquifer system. The methodology integrates geological and geotechnical data with direct drilling， offering detailed lithological information. Sedimentological， stratigraphic， and paleoenvironmental analyses enabled stratigraphic correlation and a 3D subsurface reconstruction. Four detrital sedimentary facies were identified: silts and clays， sands， gravels， and pebbles， subdivided into channel and lobe facies. The paleoenvironmental model suggests a coastal fan system (fan-delta) with occasional marine reworking at its front.
This study reconstructs the geometry of the Holocene stratigraphic framework， illustrating the depth distribution and lateral variability of deposits. Additionally， it provides a fundamental framework for improving the understanding of Valencia’s subsurface， serving as a valuable tool for future planning and development projects in the region.