التفاصيل البيبلوغرافية
| العنوان: |
Detailed 3D Structures of the Western Edge of the Pacific Large Low Velocity Province. |
| المؤلفون: |
Li, Jiewen1 (AUTHOR) lijiewen@cug.edu.cn, Zhang, Baolong2 (AUTHOR), Sun, Daoyuan3 (AUTHOR), Tian, Dongdong1 (AUTHOR), Yao, Jiayuan1 (AUTHOR) |
| المصدر: |
Journal of Geophysical Research. Solid Earth. Apr2024, Vol. 129 Issue 4, p1-18. 18p. |
| مصطلحات موضوعية: |
*VELOCITY, *IMAGING systems in seismology, *SEISMIC waves, *PROVINCES, *SHEAR waves |
| مصطلحات جغرافية: |
AFRICA |
| مستخلص: |
Large Low Velocity Provinces (LLVPs) are situated oppositely in the lowermost mantle beneath the Pacific Ocean and Africa. Deciphering the detailed seismic structures at the edge of LLVPs can provide key information on the composition and dynamics in the deep Earth. Here, we provide a detailed seismic image at the western edge of the Pacific LLVP by dense recordings. Differential travel time residuals and amplitude ratios between ScS and S outline the S‐wave western boundary of the Pacific LLVP, suggesting the complex structures including low/high‐velocity patches in the lowermost mantle in our study region. We determine the 3D low‐velocity structure by modeling the delayed ScS and high‐velocity D″ layer structure by modeling the anomalous Scd, with tight constraints from multiple events data. The drastically varied waveforms in azimuth suggests a sharp transitional boundary among the complex structures. After comparing the velocity structures in adjacent regions, we propose that the 3D structures of the western edge of the Pacific LLVP are strongly influenced by the vigorous mantle flow associated with the actively subducted slab. Plain Language Summary: Seismic studies reveal two large‐scale low‐velocity anomalies in the lowermost mantle beneath the Pacific Ocean and Africa, respectively. Resolving the detailed structures at their edges is crucial for understanding the geodynamic evolution in the deep Earth. In this study, we determine the location of the western boundary of the Pacific anomaly by the measured travel time and amplitude of seismic waves that across through our study region. Dense recordings show that there are complex structures at the western edge of the Pacific anomaly, and we determine the 3D structures by modeling the seismic recordings. We conclude that the 3D structures of the western edge of the Pacific anomaly are majorly influenced by the actively subducted materials after comparing the greatly different structures in adjacent regions. Key Points: Complex structures are present at the western edge of the Pacific Large Low Velocity Province (LLVP)Drastically varied waveforms in azimuth suggest a sharp transitional boundary among the complex structuresThe 3D structures of the western edge of the Pacific LLVP are strongly influenced by the subducted slab [ABSTRACT FROM AUTHOR] |
| قاعدة البيانات: |
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