by George Hilley (Stanford)
Jun 5, 2023
New technology-enabled discoveries to understand Earth’s seafloor for hazards and sustainability
On April 29-30, 2023, the Stanford Doerr School of Sustainability and the Stanford Graduate School of Business held a workshop titled "New Technology-Enabled Discoveries to Understand Earth’s Seafloor for Hazards and Sustainability". Aimed at gathering oceanographic research and technology development experts, the event facilitated discussions on recent advancements and the potential role of cabled arrays in MegaArray's design.
The first day centered on weighing the advantages and drawbacks of implementing a cabled array with OBS and marine geodetic stations, a series of fiber-optic cables for Distributed Acoustic Sensing (DAS), or a combination of these two technologies. Despite challenges such as harsh environments and high costs, fiber optic cables showed superior sensitivity and continuous coverage, yielding operational advantages. These advantages could be particularly beneficial to large-scale offshore geophysical projects like MegaArray, given the potential for real-time, high-quality data. However, the main downside was the cost of deployment. Importantly, it was concluded that a DAS-only cable would not suffice for the Faulting and Earthquake Cycle (FEC) group's scientific questions because of the lack of ability to capture transient geodetic signals over the appropriate amplitude and frequency band. The preferred strategy therefore appears to be an initial, reconnaissance-style array with traditional instrumentation followed by a relatively simple cable targeting a region of interest. The cable technology used by the University of Tokyo Earthquake Research Institute was of particular interest as a model as it demonstrated a low-cost solution to telemeter and power traditional instruments on the seafloor.
On the second day, the focus was on marine geophysical instrumentation applications for hazard and sustainability problems. Experts explored the use of innovative technologies like DAS and Autonomous Underwater Vehicles (AUVs). DAS, using fiber-optic cables to detect vibrations, offered new insights into earthquakes and other seismic events, and enabled monitoring of human activities threatening telecommunications infrastructure and offshore fisheries and ecosystems. Similarly, AUVs have evolved as advanced tools for high-resolution seafloor mapping, crucial for assessing seismic hazards for onshore infrastructure and burgeoning offshore green-energy systems.
Significant progress in DAS and AUV technology indicated wider applications in seafloor monitoring and hazard assessment. Advancements in machine learning and compression algorithms could potentially enable DAS to transmit larger data streams cost-effectively. Simultaneously, improved AUVs could map intricate deep-sea terrains precisely, aiding ecosystem studies and hazard assessments. With the advent of semi-autonomous vessels equipped with advanced technology, ocean exploration costs and environmental footprints could be considerably reduced. Partnerships across various sectors, coupled with scientific sensor integration into commercial infrastructure, are likely to open avenues for advancements in seafloor understanding and hazard monitoring systems in the future.