Geolocalization and Preliminary Surface Signals of Cascadia DAS Array, Port Angeles, Washington
Description:
In April 2023 our team conducted a Distributed Acoustic Sensing (DAS) experiment using dark (unlit) fiber from a 4.5 km telecommunication cable in Port Angeles, Washington, situated above the Cascadia Subduction zone. Despite the infrequency of megathrust earthquakes on this margin over the past centuries, it is an area of concern due to the high seismic hazard present. Our project focuses on leveraging onshore DAS for seismicity monitoring and gaining insights into the shallow subsurface of Port Angeles. This presentation outlines the geolocalization methods employed for channel mapping along the array, including performing and processing a tap test to map out the channel locations of the array, which is essential information for future research with this data. Additionally, preliminary findings regarding the ambient seismic noise field recorded by the high-resolution DAS array will be discussed. The continuous sampling along the fiber allows for both high spatial and temporal resolution, making it valuable for monitoring the subsurface along the array. The array has picked up a myriad of cultural and noise signals, including traffic from a nearby highway and bike/foot traffic along an adjacent path. These passive seismic signals will be used for ambient noise tomography to deduce information about properties and structures of sediments below the array, but the appropriate use of ambient noise first requires careful characterization of the noise prior to interferometry and tomography. We will examine the characteristics of these ambient/cultural seismic signals including their spatial and temporal distribution and the variations in their frequency content. This analysis sets the groundwork for utilizing ambient noise tomography to estimate shallow shear wave velocities in the subsurface, crucial for assessing ground motion hazard in the Port Angeles area.
Session: Advancing Seismology with Distributed Fiber Optic Sensing [Poster Session]
Type: Poster
Date: 5/3/2024
Presentation Time: 08:00 AM (local time)
Presenting Author: Halina
Student Presenter: Yes
Invited Presentation:
Authors
Halina Dingo Presenting Author Corresponding Author hadi3153@colorado.edu University of Colorado Boulder |
Anne Sheehan anne.sheehan@colorado.edu University of Colorado Boulder |
Manuel Mendoza manuel.mendoza@colorado.edu University of Colorado Boulder |
Eileen Martin eileenrmartin@mines.edu Colorado School of Mines |
|
|
|
|
|
Geolocalization and Preliminary Surface Signals of Cascadia DAS Array, Port Angeles, Washington
Session
Advancing Seismology with Distributed Fiber Optic Sensing