Turning fiber optic cables into next-generation seismic networks

Zhongwen Zhan, California Institute of Technology

Seismology is one of the main approaches to study quakes and image Earth and planetary interiors. However, deploying large-scale dense seismic networks has been challenging. Distributed acoustic sensing (DAS) is an emerging technology that converts every few meters of a long (currently tens of km) optical fiber into a seismic strainmeter. At its most basic level, DAS works by shining a laser pulse into the fiber from one end and interrogating the “echo” of Rayleigh scattering from intrinsic fiber defects. DAS provides a scalable and affordable way to deploy a dense seismic network, by installing dedicated fiber cables or leveraging existing telecommunication fiber networks. In the last two years, Zhan has been exploring the potential of DAS in the next generation seismic networks on different scales. More specifically, Zhan tests DAS in earthquake detection, structure inversion, and hazard assessment. In this talk, Zhan will give an overview of those efforts and a vision for the future.