Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray
Recent advancements in seismic data analysis have enhanced our grasp of the seismic heterogeneities near the core–mantle boundary (CMB). Through seismic tomography, persistent lower-mantle structures like the large low shear velocity provinces (LLSVPs) beneath the Pacific and South Africa have been...
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MDPI AG
2024-11-01
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| author | Yenting (Justin) Ko Kai-Jie Hu |
| author_facet | Yenting (Justin) Ko Kai-Jie Hu |
| author_sort | Yenting (Justin) Ko |
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| description | Recent advancements in seismic data analysis have enhanced our grasp of the seismic heterogeneities near the core–mantle boundary (CMB). Through seismic tomography, persistent lower-mantle structures like the large low shear velocity provinces (LLSVPs) beneath the Pacific and South Africa have been identified. However, variations in the finer-scale features across different models raise questions about their origins. This study utilizes differential travel-time measurements from the USArray, operational across the contiguous United States from 2007 to 2014, to examine the impact of upper-mantle heterogeneities on tomographic models. By averaging the P-wave travel times and calibrating them with diffracted P-waves at the same stations, we mitigate the effects of shallow heterogeneities. The findings confirm that this method accurately maps the seismic anomalies beneath the USArray, consistent with other North American studies. Calibrated Pdiff travel-time data indicate significant anomalies in the mid-Pacific and Bering Sea and lesser anomalies in the northern Pacific, aligning with the global tomographic images. Moreover, the study highlights sharp travel-time variations over short distances, such as those across the northern boundary of the mid-Pacific anomaly, suggesting a chemically heterogeneous Pacific LLSVP. |
| format | Article |
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| institution | Kabale University |
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| language | English |
| publishDate | 2024-11-01 |
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| spelling | doaj-art-5b87e9dc2f444340a0e8548baf3b5edb2024-11-26T18:05:42ZengMDPI AGGeosciences2076-32632024-11-01141130910.3390/geosciences14110309Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArrayYenting (Justin) Ko0Kai-Jie Hu1Institute of Oceanography, National Taiwan University, Taipei 106319, TaiwanInstitute of Oceanography, National Taiwan University, Taipei 106319, TaiwanRecent advancements in seismic data analysis have enhanced our grasp of the seismic heterogeneities near the core–mantle boundary (CMB). Through seismic tomography, persistent lower-mantle structures like the large low shear velocity provinces (LLSVPs) beneath the Pacific and South Africa have been identified. However, variations in the finer-scale features across different models raise questions about their origins. This study utilizes differential travel-time measurements from the USArray, operational across the contiguous United States from 2007 to 2014, to examine the impact of upper-mantle heterogeneities on tomographic models. By averaging the P-wave travel times and calibrating them with diffracted P-waves at the same stations, we mitigate the effects of shallow heterogeneities. The findings confirm that this method accurately maps the seismic anomalies beneath the USArray, consistent with other North American studies. Calibrated Pdiff travel-time data indicate significant anomalies in the mid-Pacific and Bering Sea and lesser anomalies in the northern Pacific, aligning with the global tomographic images. Moreover, the study highlights sharp travel-time variations over short distances, such as those across the northern boundary of the mid-Pacific anomaly, suggesting a chemically heterogeneous Pacific LLSVP.https://www.mdpi.com/2076-3263/14/11/309diffracted wavescore-mantle boundarytravel-time anomaliesupper mantle correctionsPacific LLSVP |
| spellingShingle | Yenting (Justin) Ko Kai-Jie Hu Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray Geosciences diffracted waves core-mantle boundary travel-time anomalies upper mantle corrections Pacific LLSVP |
| title | Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray |
| title_full | Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray |
| title_fullStr | Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray |
| title_full_unstemmed | Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray |
| title_short | Refining Heterogeneities near the Core–Mantle Boundary Beneath East Pacific Regions: Enhanced Differential Travel-Time Analysis Using USArray |
| title_sort | refining heterogeneities near the core mantle boundary beneath east pacific regions enhanced differential travel time analysis using usarray |
| topic | diffracted waves core-mantle boundary travel-time anomalies upper mantle corrections Pacific LLSVP |
| url | https://www.mdpi.com/2076-3263/14/11/309 |
| work_keys_str_mv | AT yentingjustinko refiningheterogeneitiesnearthecoremantleboundarybeneatheastpacificregionsenhanceddifferentialtraveltimeanalysisusingusarray AT kaijiehu refiningheterogeneitiesnearthecoremantleboundarybeneatheastpacificregionsenhanceddifferentialtraveltimeanalysisusingusarray |