@article {xu_constraints_2023, title = {Constraints on the structure of the oceanic crust of the Tamu Massif by teleseismic P-wave coda autocorrelation}, journal = {Frontiers in Earth Science}, volume = {11}, year = {2023}, abstract = {The Tamu Massif, considered the biggest single volcano on Earth, was formed by the accumulation of enormous amounts of magma erupting to the surface. It is the largest and oldest seamount in Shatsky Rise, which is the third largest oceanic plateau on Earth. However, the formation mechanism of Tamu Massif is still controversial because evidence point to different formation hypotheses. In this paper, we applied the P-wave coda autocorrelation method and used the hydrophone waveform data acquired by the ocean bottom seismometer (OBS) deployed on Tamu Massif to constrain the oceanic crust, and these results provide new finding on the structure of the oceanic crust for Tamu Massif. We hope it can provide some implications to research the formation mechanism of Tamu Massif. These results show that some stations in Tamu Massif received reflection signals from shallower depths that are nearly parallel to the seafloor. We infer that in the shallow oceanic crust, there is a layer composed of alternating eruptions of dense, higher velocity massive lava and sparse, lower velocity pillow lava flows, which have less density and lower velocity compared to the lower oceanic crust, with a strong acoustic impedance contrasts between them and thus able to generate a reflection signal, which is observed in our autocorrelation results.}, issn = {2296-6463}, url = {https://www.frontiersin.org/articles/10.3389/feart.2023.1218576}, author = {Xu, Fucong and Lu, Shaoping and Cai, Chen and Chen, Han and Dong, Shaozhe} } @article {deng_theoretical_2022, title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Waves at High Frequencies}, journal = {Geophysical Research Letters}, volume = {49}, number = {9}, year = {2022}, note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2021GL096952}, pages = {e2021GL096952}, abstract = {Previous studies have demonstrated that the ocean-bottom pressure associated with seismic seafloor motion is linearly proportional to the vertical seafloor acceleration, for frequencies much lower than the resonance frequency of water layer (c0/4h, c0 water sound speed, h water depth). In this article, we use realistic observations to verify a theoretical relation between the ocean-bottom pressure and vertical acceleration up to the water resonance frequency. We then show two applications of the theoretical relation. First, the pressure amplitude recorded by differential pressure gauges is calibrated, and the calibration coefficient is found to vary by frequency. Second, Rayleigh wave phase velocity near the water resonance frequency can be calculated from recordings of pressure and vertical seafloor acceleration at a single station, which is useful to constrain the shallow Earth structure.}, issn = {1944-8007}, doi = {10.1029/2021GL096952}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2021GL096952}, author = {Deng, Han and An, Chao and Cai, Chen and Ren, Hengxin} } @article {eimer_seismicity_2020, title = {Seismicity of the Incoming Plate and Forearc Near the Mariana Trench Recorded by Ocean Bottom Seismographs}, journal = {Geochemistry, Geophysics, Geosystems}, volume = {21}, number = {4}, year = {2020}, note = {_eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020GC008953}, month = {04/2020}, pages = {e2020GC008953}, abstract = {Earthquakes near oceanic trenches are important for studying incoming plate bending and updip thrust zone seismogenesis, yet are poorly constrained using seismographs on land. We use an ocean bottom seismograph (OBS) deployment spanning both the incoming Pacific Plate and the forearc to study seismicity near the Mariana Trench. The yearlong deployment in 2012{\textendash}2013 consisted of 20 broadband OBSs and 5 suspended hydrophones, with an additional 59 short period OBSs and hydrophones recording for 1 month. We locate 1,692 earthquakes using a nonlinear method with a 3D velocity model constructed from active source profiles and surface wave tomography results. Events occurring seaward of the trench occur to depths of 35 km below the seafloor, and focal mechanisms of the larger events indicate normal faulting corresponding to plate bending. Significant seismicity emerges about 70 km seaward from the trench, and the seismicity rate increases continuously towards the trench, indicating that the largest bending deformation occurs near the trench axis. These plate-bending earthquakes occur along faults that facilitate the hydration of the subducting plate, and the lateral and depth distribution of earthquakes is consistent with low-velocity regions imaged in previous studies. The forearc is marked by a heterogeneous distribution of low magnitude (<5 Mw) thrust zone seismicity, possibly due to the rough incoming plate topography and/or serpentinization of the forearc. A sequence of thrust earthquakes occurs at depths 10 km below seafloor and within 20 km of the trench axis, demonstrating that the megathrust is seismically active nearly to the trench.}, issn = {1525-2027}, doi = {10.1029/2020GC008953}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2020GC008953}, author = {Eimer, Melody and Wiens, Douglas A. and Cai, Chen and Lizarralde, Daniel and Jasperson, Hope} } @article {Cai2018, title = {Water input into the Mariana subduction zone estimated from ocean-bottom seismic data}, journal = {Nature}, volume = {563}, number = {7731}, year = {2018}, month = {nov}, pages = {389{\textendash}392}, issn = {0028-0836}, doi = {10.1038/s41586-018-0655-4}, url = {http://www.nature.com/articles/s41586-018-0655-4}, author = {Cai, Chen and Wiens, Douglas A. and Shen, Weisen and Eimer, Melody} } @article {Wei2017, title = {Slab temperature controls on the Tonga double seismic zone and slab mantle dehydration}, journal = {Science Advances}, volume = {3}, number = {1}, year = {2017}, month = {jan}, pages = {e1601755}, issn = {2375-2548}, doi = {10.1126/sciadv.1601755}, url = {https://advances.sciencemag.org/lookup/doi/10.1126/sciadv.1601755}, author = {Wei, S. Shawn and Wiens, Douglas A. and van Keken, Peter E. and Cai, Chen} } @article {An2017, title = {Theoretical Solution and Applications of Ocean Bottom Pressure Induced by Seismic Seafloor Motion}, journal = {Geophysical Research Letters}, volume = {44}, number = {20}, year = {2017}, month = {oct}, pages = {10,272{\textendash}10,281}, issn = {00948276}, doi = {10.1002/2017GL075137}, url = {http://doi.wiley.com/10.1002/2017GL075137}, author = {An, Chao and Cai, Chen and Zheng, Yong and Meng, Lingsen and Liu, Philip} }