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- Description:
- We deployed a Nanometrics Trillium Compact 20-s, three-component broadband seismometer on the summit of Devils Tower between October 12-13, 2024. The instrument was hauled and carried to the summit by a team of climbers under an approved permit from the National Park Service. The seismometer (labelled station D) was located on the northern portion of the tower summit. It was placed on bare bedrock, with a dab of adhesive putty under each foot to aid coupling, leveled and oriented north, and then covered to prevent wind buffeting. The seismometer was paired with a 24-bit Nanometrics Centaur datalogger recording continuous data at 100 Hz. Two additional identical seismometer setups were also deployed: station C on bedrock near the base of the tower’s south wall, and station A on a large flat boulder embedded in colluvium ~200 m south of the tower. The various instruments had different run times: station D on top of the tower ran the longest for 21 hours from afternoon to late morning, while the overlapping duration of the three sensors was 19 hours (10/12 20:00 to 10/13 15:00 UTC).
- Keyword:
- national parks, modal analysis, and seismology
- Subject:
- seismology and modal response
- Creator:
- Moore, Jeffrey R., Vollinger, Kathryn, and Burjánek, Jan
- Owner:
- Jeff Moore
- Based Near Label Tesim:
- Devils Tower, Wyoming, United States
- Language:
- English
- Date Uploaded:
- 05/14/2025
- Date Modified:
- 05/28/2025
- Date Created:
- 2024-10-12 to 2024-10-13
- License:
- CC BY NC - Allows others to use and share your data non-commercially and with attribution.
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S5d-ajvn-wqqq
-
- Description:
- We analyzed 4,754 broadband seismic recordings of the SKS, SKKS, and SPdKS wavefield from 13 high quality events sampling the Samoa ultralow-velocity zone (ULVZ). We measured differential travel-times and amplitudes between the SKKS and SKS arrivals, which are highly sensitive to the emergence of the SPdKS seismic phase, which is in turn highly sensitive to lowermost mantle velocity perturbations such as generated by ULVZs. We modeled these data using a 2-D axi-symmetric waveform modeling approach and are able to explain these data with a single ULVZ. In order to predict both travel-time and amplitude perturbations we found that a large ULVZ length in the great circle arc direction on the order of 10° or larger is required. The large ULVZ length limits acceptable ULVZ elastic parameters. Here we find that δVS and δVP reductions from 20% to 22% and 15% to 17% respectively gives us the best fit, with a thickness of 26 km. Initial 3-D modeling efforts do not recover the extremes in the differential measurements, demonstrating that 3-D effects are important and must be considered in the future. However, the 3-D modeling is generally consistent with the velocity reductions recovered with the 2-D modeling. These velocity reductions are compatible with a compositional component to the ULVZ. Furthermore, geodynamic predictions for a compositional ULVZ that is moving predict a long linear shape similar to the shape of the Samoa ULVZ we confirm in this study. and This collection includes radial component displacement seismograms in the time window including the SKS, SKKS and SPdKS seismic arrivals. These data all interact with the Samoa ultra-low velocity zone at the core-mantle boundary. All data used in the study of Krier et al., 2021 (JGR) is included in this collection.
- Keyword:
- seismology, Samoa hot spot, geodynamic predictions model, 3-D model, ULVZ, and ultra-low velocity zone
- Subject:
- Geology, seismology, and Geophysics
- Creator:
- Thorne, Michael S. , Nissen-Meyer, Tarje , Krier, Justin D. , and Leng, Kuangdai
- Owner:
- Michael Thorne
- Based Near Label Tesim:
- Tonga Trench, , Tonga
- Language:
- English
- Date Uploaded:
- 02/17/2021
- Date Modified:
- 10/25/2024
- Date Created:
- 2019-01-01 to 2020-01-31
- License:
- Public Domain – This data is free of copyright restrictions (e.g. government sponsored data).
- Resource Type:
- Dataset
- Identifier:
- https://doi.org/10.7278/S50DT3X22GGB