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- Description:
- The dataset contains velocity measurements along the fiber optic cable connecting the University of Utah campus to the University of Utah Downtown data center (875 West Temple, Salt Lake City, UT). The data has been collected using the Distributed acoustic sensing (DAS) system that records the vibration signals along 8.4 km long optical fiber every 4.9-m interval with a sampling rate of approximately 1000 Hz. The fiber is mainly installed along the red line of TRAX, which is the light rail system of the Utah Transit Authority. The route intersects the East Bench fault, which is known as an active fault segment of the Wasatch Fault zone. Although no earthquake signals were detected, the velocity data converted to strain rate clearly show the operation of trains between the stations at 450 S Main Street and 900 South 200 West. Analysis of this dataset is expected to provide insights into seismic velocities at shallow depths and structures associated with fault scarps. and See README file for data retrieval instructions.
- Keyword:
- seismology, urban seismology, distributed acoustic sensing, fiber optic cable, and strain rate
- Subject:
- Geophysics, Seismology, Seismology--Observations, and Surface fault ruptures
- Creator:
- Kim, HyeJeong and Lin, Fan-Chi
- Contributor:
- Chambers, Derrick
- Owner:
- Kaylee Alexander
- Based Near Label Tesim:
- Salt Lake City, Utah, United States
- Language:
- English
- Date Uploaded:
- 07/01/2024
- Date Modified:
- 10/10/2024
- Date Created:
- 20230524 to 20230526 (period 1), 20230803 to 20230811 (period 3), 20231222 to 20240102 (period 4), and 20230629 to 20230710 (period 2)
- License:
- CC BY NC - Allows others to use and share your data non-commercially and with attribution.
- Identifier:
- https://doi.org/10.7278/S5d-kgxx-ev8y
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- Description:
- Ultralow-velocity zones (ULVZs) have been studied using a variety of seismic phases; however, their physical origin is still poorly understood. Short period ScP (S wave converted to, and reflected as, P wave from the core-mantle boundary) waveforms are extensively used to infer ULVZ properties because they may be sensitive to all ULVZ elastic moduli. However, ScP waveforms are additionally complicated by the effects of path attenuation, coherent noise, and source-time function (STF) complexity. To address these complications, we developed a hierarchical Bayesian inversion method that allows us to invert ScP waveforms from multiple events simultaneously and accounts for path attenuation and correlated noise. The inversion method is tested with synthetic predictions which show that the inclusion of attenuation is imperative to recover ULVZ parameters and that the ULVZ thickness and S-wave velocity decrease (δVS) are most reliably recovered. Utilizing multiple events reduces the effects of coherent noise and STF complexity, which in turns allows for the inclusion of more data to be used in the analyses. We next applied the method to ScP data recorded in Australia for 291 events that sample the CMB beneath the Coral Sea. Our results indicate that S-wave velocity across the region is ~-14% in average, but there is a greater variability in the south than that in the north. P-wave velocity reductions and density perturbations are mostly below 10%. These ScP data show more than one ScP post-cursor in some areas which may indicate complex 3-D ULVZ structures. Seismic data are provided for 291 earthquakes in Northern Territory, Australia.
- Keyword:
- seismology, mantel phases, ULVZ, and short period ScP waveforms
- Subject:
- Geology, Seismology, and Geophysics
- Creator:
- Pachhai, Surya and Thorne, Michael S.
- Owner:
- Surya Pachhai
- Based Near Label Tesim:
- Northern Territory, Northern Territory, Australia
- Language:
- English
- Date Uploaded:
- 12/10/2022
- Date Modified:
- 06/03/2024
- Date Created:
- 2005-01-01 to 2021-12-30.
- License:
- Public Domain – This data is free of copyright restrictions (e.g. government sponsored data).
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50d-a67s-y717