Speaker：Dr. Zhichao Shen (Department of Geology and Geophysics, Woods Hole Oceanographic Institution)
Title：Enhancing Climate Resilience with Distributed Acoustic Sensing (DAS): from Land to the Sea.
Time：12/9 (Tue) 10:30
Location：R215 of IONTU
Abstract:
In the face of climate variability, quantifying the dynamics of Earth’s hydrosphere across time and space is crucial for understanding the interconnected systems of the atmosphere, ocean, and solid earth. Distributed acoustic sensing (DAS), that converts ubiquitous fiber-optic cables into extensive networks of seismic sensors, presents a cost-effective seismic sensing tool for characterizing Earth’s water reservoirs over large spatiotemporal scales, thereby enhancing our climate resilience. In this talk, I will demonstrate how DAS can be employed to capture subsurface (vadose zone) water dynamics through fiber-optic seismic sensing, and to measure ocean temperature changes via seismic ocean thermometry (SOT). For the subsurface part, I will first introduce the fiber-optic seismic sensing principle by combining DAS with 4D seismology and rock physics. The first application of fiber seismic sensing to a DAS array in Ridgecrest, CA, revealed sub-seasonal precipitation replenishments and a prolonged drought in the vadose zone spanning over 2.5 years in fine spatial resolution. For the ocean part, I will illustrate how ocean bottom DAS can improve the detection capability of ocean seismo-acoustic waves (i.e., T-waves), which makes more small repeating earthquakes useable for global SOT applications. In conclusion, DAS can offer a scalable, long-term solution for large scale environmental monitoring, making it an invaluable tool toward better climate adaptation and preparation.
