Recently, a team led by Dr. Zhao Minghui, a researcher at the Key Laboratory of Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, along with collaborators, utilized data from mobile seismic stations deployed on Sulawesi Island to investigate the deformation patterns in the upper mantle under the interaction of multiple subduction systems. The findings were published in the Journal of Geophysical Research-Solid Earth.
Research on the splitting of near-source S waves and far-source S/SKS waves at all stations. Research team provides figures.
The northern Sulawesi block in Indonesia exhibits unique geological characteristics, situated at a convergent boundary of multiple tectonic plates. With frequent tectonic activities in the Cenozoic era, it has become a hotspot for studying mantle flow and lithospheric deformation. Researchers conducted a detailed analysis using seismological methods, specifically shear wave splitting techniques, on near-source S waves, far-source S waves, and SK(K)S waveforms.
The results indicate that the seismic anisotropy around the northern Sulawesi block is closely related to the interaction of multiple subducting slabs. Firstly, during the subduction of the Sangihe Plate and the Sulawesi Sea Plate, typical mantle wedge convection phenomena were observed. However, the mantle wedge convection pattern of the Sulawesi Sea Plate is significantly influenced by its arcuate plate morphology. In the Tomini Bay, researchers observed fast wave directions oblique to the northern Sulawesi Trench, suggesting a possible result of the interaction between two subducting plates. Additionally, the mantle wedge formed by the subduction of the Sulawesi Sea Plate exhibits an east-west fast wave direction at its southernmost end, implying a potential barrier effect caused by the subduction of the southern Sulawesi Plate.
The North Sulawesi Block: Deformation Patterns of the Lithosphere and Upper Mantle Under the Influence of Multiple Slab Subductions. Research Team Provided Image.
This study, conducted by the research team led by Dr. Zhao Minghui from the Key Laboratory of Marginal Sea Geology at the South China Sea Institute of Oceanology, Chinese Academy of Sciences, in collaboration with the Department of Earth Sciences at the University of Cambridge, Institute of Geology and Geophysics, Chinese Academy of Sciences, Bandung Institute of Technology in Indonesia, University of Western Australia, and Zhejiang Ocean University, offers valuable seismic evidence for understanding the deformation of the upper mantle in the complex multi-subduction system of the North Sulawesi Block in Indonesia. In the future, such in-depth seismic-based research is expected to provide richer information for predicting crustal stability and disaster prevention.
This research was jointly funded by the Major Program of the National Natural Science Foundation of China, the Strategic Priority Research Program of the Chinese Academy of Sciences (Category B), the National Natural Science Foundation of China, the Isaac Newton Trust Fund in the UK, and the UK Global Challenges Research Fund. The co-corresponding authors of the paper are Dr. Cao Lingmin, Associate Researcher at the South China Sea Institute of Oceanology, Chinese Academy of Sciences (first author of the paper), Dr. Lv Chuanchuan from the University of Cambridge, and Dr. He Xiaobo from Zhejiang Ocean University.
For more information on the paper, please visit: https://doi.org/10.1029/2023JB028110
