Safer Buildings, Smarter Energy: Singapore Seismic Study's Impact

Seismic Study Unveils Earthquake Risk and Geothermal Potential in Singapore

A recent seismic study of Singapore uncovered important knowledge on earthquake risk and geothermal potential in Singapore. The study, published in Seismological Research Letters, uncovers areas susceptible to ground shaking and provides evidence of a potential underground heat source at Sembawang Hot Spring.

The research, led by China University for Geosciences's Jiayuan Yao and co-authors, used teleseismic waves from permanent seismic stations and a temporary nodal array in 2019. The result gives the complete profile of Singapore's uppermost underground layers, and the results will contribute to urban planning, along with determining renewable resources.

Ground Shaking Risks in Soft Sediments
One of the most important findings from the study is that soft-sediment areas, especially reclaimed land along Singapore's east coast, can be subjected to increased seismic ground motion. Approximately 20% of Singapore consists of reclaimed land where sand was dumped to gain additional usable space. Seismic waves traveling through the soft sediments are found to be amplified in amplitude by the study, leading to more intense ground shaking.

Singapore itself is just a few hundred kilometers from the Sunda megathrust zone, one of the most seismically active areas on Earth. It was here that the deadly 2004 Indian Ocean earthquake and tsunami killed nearly 230,000 people. Although Singapore itself has not been famous for catastrophic earthquakes, it is necessary to understand seismic wave behavior in various soils and rocks in order to determine the possible hazard.

The findings of the study suggest the need to include geological conditions in seismic risk assessment and infrastructure planning. The information can be utilized by authorities to enhance building codes, particularly for high-risk zones with soft sediments.

Geothermal Potential
The research also detected a seismic anomaly at Sembawang Hot Spring in the north of Singapore. This is a zone of low velocity from the surface to about 5 kilometers below the surface, and this may imply potentially an underlying heat source within the Earth's crust.

Researchers think that the heat is supplied by high mantle heat flow or radioactive decay of the underlying granite formations. Granite fractures may be a way of tapping geothermal energy, and it has the potential to be a good source of renewable energy for Singapore.

But the researchers said that further studies are required. A denser nodal seismic array surrounding Sembawang Hot Spring would enable improved subsurface mapping and would ascertain the viability of geothermal energy production.

Singapore's Tectonic History
By correlating their observations with earlier geological mapping, the scientists pieced together a probable tectonic history of Singapore. Central and eastern Singapore's bedrock was created between 250 and 230 million years ago as a result of subduction of the Paleo-Tethys oceanic slab beneath the East Malaya Terrane during magmatic activity, according to the study.

Western Singapore sedimentary deposits, nonetheless, correspond with the Sukhothai volcanic island-arc system between 230 to 220 million years ago. Through such observations, geologists make inferences concerning the geological history of Singapore as well as the latter's connectivity to seismic events taking place.

Future Research Directions
Further studies using ambient noise data are being designed by the research team to investigate Singapore's subsurface architecture in its shallow depths. Seismic velocity changes that are weak can also be useful to monitor underground water storage, which is beneficial for water resource management and ground stability.

The outcomes of the study apply to Singapore's urban planning, disaster risk management, and future renewable energy projects. With ongoing research, the country can improve seismic resilience and find new sources of clean energy.