Large-scale crustal structure beneath Singapore using receiver functions from a dense urban nodal array

Abstract

Geophysics has a role to play in the development of 'smart cities', for example through geohazard mitigation and subsurface imaging for underground construction. This is particularly true for Singapore, one of the world's most densely populated countries. Imaging of Singapore's subsurface is required to identify geological faults, model shaking from future earthquakes and provide a framework for underground development. A non-invasive geophysical technique that is well suited for urban areas is passive seismic surveys using nodes. Here, we image Singapore's crustal structure using receiver functions generated by a 40-day deployment of a dense nodal array. We generate high resolution receiver functions, despite the noisy environment and short recording time and also create common-conversion point images. Our results reveal a complex crustal structure, containing multiple discontinuities. Azimuthal variations indicate a distinct change in crustal structure on either side of the postulated Bukit Timah fault, which has implications for seismic hazard.

Urban Basin Structure Imaging Based on Dense Arrays and Bayesian Array‐Based Coherent Receiver Functions

“…To address these challenges, passive source methods using earthquake data and ambient noise have been used in mapping basin structure in urban areas (Agostinetti et al., 2018; Cunningham & Lekic, 2019; Finlay et al., 2019; Lin et al., 2013; Liu et al., 2018; Ma & Clayton, 2016; Viens et al., 2016; Yeck et al., 2013). The development of easy‐to‐deploy and robust nodal‐type sensors has further facilitated the deployment of large‐N arrays in urban environments for high‐resolution basin imaging (Clayton, 2020; Finlay et al., 2019; Lin et al., 2013; Liu et al., 2018; Lythgoe et al., 2020).…”

Big Data Seismology

“…High‐resolution velocity models can provide important constraints for earthquake hazard assessment, which relies on models of peak ground acceleration (Castellanos & Clayton, 2021), a property that is very sensitive to crustal properties and can vary spatially across multiple scales. Nodal arrays have subsequently been deployed in other urban areas including Albuquerque and Singapore (Finlay et al., 2020; Lythgoe et al., 2020). As discussed in the section on non‐earthquake sources, sensors in urban environments record a rich variety of signals from anthropogenic sources.…”