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Session: Urban Seismology [Poster]

Type: Poster

Date: 10/9/2024

Time: 07:00 AM

Room: Stanley Park Ballroom

Addressing Challenges of Accurately Measuring Earthquake Ground Motions Using Commercial Dark Fiber in an Urban Environment

Seismic monitoring using conventional broadband seismometers can be challenging in urban environments due to limitations of land access. To evaluate the use of fiber optic sensing in urban environments, we interrogate ~95 km-long pre-existing dark fiber in an area with heavy traffic in Dallas, Texas, using a strain Interrogator Unit. To compare with traditional seismometers, we deployed 10 three-component broadband seismometers at different locations along the fiber cable and tested the Distributed Acoustic Sensing (DAS) on different configurations. We observed some known and unknown challenges with using the commercial dark fiber to retrieve reliable estimates of ground motion. These include the presence of aerial fiber sections, slack fiber in handholes, and varying fiber cable coupling with the ground. We have provided a computational-based solution for the identification of sections of fiber that cannot be used to retrieve reliable ground motions. In addition, we provided a criterion for using the Frequency-Wavenumber (F-K) transform technique to convert the DAS strain to ground velocities with different ground coupling conditions. Using a modified F-K transform technique, we have reliably matched the earthquake ground velocity records of DAS with seismometer recordings.

Presenting Author: Jyoti

Additional Authors