[S-CG45] Science of slow-to-fast earthquakes

[SCG45-11] Fault zone characterization using scattered waves recorded by distributed acoustic sensing

★Invited Papers

*Yan Yang¹、James Atterholt¹、Zhongwen Zhan¹ (1.California Institute of Technology)

キーワード：Distributed acoustic sensing, Fault zones

Earthquake ruptures are controlled by fault zones at different scales. However, it is challenging to characterize fault zone structures at sub-kilometer scales, especially in urban settings where identifying faults is essential for hazard assessment. Here we present new methods for characterizing fault zones at sub-kilometer scales using distributed acoustic sensing (DAS). DAS technique can repurpose existing telecommunication cables into dense array of strainmeters. With dense sensors at several meters’ spacing, the unaliased wavefield can provide unprecedented details for fault zones. In this work, we use a DAS array converted from a 10-km underground fiber-optic cable across Ridgecrest City, California. We report clear body-to-surface wave scattering in local earthquakes and surface-to-surface wave scattering in noise interfereometry. We use both observations to locate and characterize the faults across the Ridgecrest city. The two individual methods lead to consistent fault locations, geometry, and properties. These findings demonstrate the potential of DAS for detecting and imaging of fine-scale faults in an urban environment.