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UID:seminar-15383@epss.ucla.edu
DTSTAMP:20260522T193452Z
DTSTART:20260603T153000Z
DTEND:20260603T163000Z
SUMMARY:Geophysics &#038\; Geology (245/287): Yang Ma &#8211\; Using Distributed Acoustic Sensing to Study the Static Deformation of Moderate Earthquakes
DESCRIPTION:Speaker: Yang Ma
Affiliation: EPSS\, UCLA
Date: Wednesday\, June 3\, 2026
Time: 12:00 PM

Abstract
 Static\, long-term deformation generated by earthquakes provides essential constraints on fault slip\, stress redistribution\, and crustal rheology. However\, measuring earthquake-induced static deformation remains challenging\, particularly for moderate earthquakes\, due to their small strain amplitudes. Traditional geodetic observations\, such as high-frequency Global Navigation Satellite System (GNSS) and tiltmeter measurements\, are susceptible to noise and limited in spatial resolution. Fortunately\, Distributed Acoustic Sensing (DAS) offers a novel technology by converting pre-existing optical fiber into thousands of dense strain sensors\, enabling high-resolution observations over large areas. This approach has been successfully applied to monitor static deformation associated with magma migration in volcanic systems. Here\, using DAS data from the Taiwan Milun Fault Drilling and All-inclusive Sensing (MiDAS) project\, we demonstrate that static strain from more than a dozen aftershocks (Ml &gt\; 5) following the 2024 Mw 7.4 Hualien earthquake can be clearly recorded. Interestingly\, at short spatial scales (~100 m)\, the strain field exhibits complex patterns\, with even alternating extensional and compressional signals. Through numerical simulations\, we hypothesize that this phenomenon is linked to anomalies in the medium&#39\;s Poisson&#39\;s ratio\, which is consistent with the fractured structure of the Milun Fault. Overall\, our results highlight DAS as a reliable complement to conventional geodetic observations\, offering a useful tool for investigating seismic deformation fields.
URL:https://epss.ucla.edu/geophysics-geology-245-287-yang-ma-using-distributed-acoustic-sensing-to-study-the-static-deformation-of-moderate-earthquakes/
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