Seismic Structure of Singapore: Implications for Tectonics, Geothermal Energy Utilization, and Seismic Hazard Estimation

Abstract High-precision urban subsurface geophysical imaging is critical for city development, including urban construction, seismic hazard assessment, and renewable energy development. We investigate the top 5 km VS, sediment thickness, Moho depth, and crustal average VP/VS of Singapore using teleseismic P-wave polarizations and receiver functions from a nodal array and some permanent stations. We present the first sediment model of Singapore, which shows the thickest compacted sediments (∼1.2 km) in the west, negligible sediments in central area and some localized sediments in the east (∼0.8 km) and northwest (∼1.1 km). Based on the new crustal model and previous geological surveys, we discuss a possible tectonic evolutionary history of Singapore, which is related to the subduction of the Paleo-Tethys slab. The observed low-VS anomaly beneath the Sembawang hot spring reveals its possible deep heat source, indicating a potential source of geothermal energy in Singapore. In addition, ground-motion amplification variations caused by local site conditions across Singapore are estimated, showing that areas of soft sediment, especially the reclaimed land in the east, have the highest seismic risk.