Today, over half of the world’s population lives in urban areas with a projected growth to more than two-thirds in 2050. The city-state of Singapore faces the challenges of supporting a sustainable urban system with growing population in a limited land, sea, and air space. The only direction to develop is toward the subsurface. Conventional geophysical methods are not applicable because of their disruptions to urban activities, deteriorated performance due to strong anthropogenic interference, and unsatisfying spatial and temporal resolution. In this webinar, we present recent advances in passive sensing to harvest the urban noise from traffic, construction, and ocean waves with small, dense arrays. We design novel signal processing techniques that turn urban hum to rich information of the urban system, both above and below surface. The resulting meter-scale spatial resolution and minute-scale temporal resolution are the cornerstones to meeting engineering demands in urban environments. We present newly developed fiber sensing technology using existing dark fiber infrastructure that has the potential to enable a million-sensor system underneath each major city around the globe. Applications of these techniques in shallow bedrock mapping, deep aquifer identification, and near-surface monitoring for geohazards provide the opportunity for geophysicists to contribute directly to urban society in planning, managing, and monitoring its space, water, infrastructure and other resources.
Dr. Elita Li
Dr. Elita Li joined the Department of Civil and Environmental Engineering at the National University of Singapore as an assistant professor in 2016. Before coming to Singapore, Dr. Li did her postdoctoral research at Massachusetts Institute of Technology, holding a joint position in the Earth Resources Laboratory and the Department of Mathematics. Dr. Li received her PhD and M.S. degrees in Geophysics from Stanford University in 2014 and 2010, respectively. She obtained her B.S. degree in Information and Computational Science from China University of Petroleum, Beijing in 2008. At NUS, Elita’s research group works on geophysical applications in urban environments for smart city developments. By integrating ambient noise imaging and distributed sensor networks, the research efforts are focused on the development of a noninvasive, high-resolution, and real-time listening system to solve pressing urban challenges in space, water, and society. Elita was the recipient of the J. Clarence Karcher Award from SEG in 2018 and the SEG South & East Asia Honorary Lecturer for 2022.