3D transdimensional seismic tomography of the inner core
نویسندگان
چکیده
Body wave observations of the Earth's inner core show that it contains strong seismic heterogeneity, both laterally and radially. Models structure generated using body data are often limited by their parameterisation. Thus, is difficult to determine whether features such as anisotropic hemispheres or an innermost truly exist with simple shapes, result only from chosen parameterisation in fact more complex features. To overcome this limitation, we conduct tomography transdimensional Markov Chain Monte Carlo on a high quality dataset 5296 differential 2344 absolute P-wave travel times. In approach, defines model space parameterisation, providing us mean value each parameter its probability distribution, allowing identify well versus poorly constrained regions. We robustly recover many first order found previous studies without imposition priori fixed geometry including isotropic top layer (with anisotropy less than 1%) which between 60 170 km thick, separated into slow west faster east. Strong maximum 7.2%) mainly west, much weaker observe for time western zone largely confined northern hemisphere, property would not be recognised models assuming hemispherical further find most core, slowest velocity direction tilted relative axis rotation (?=55?±16?), offset 400 centre restricted eastern hemisphere. propose anomalous might indicate presence different phase iron (either bcc fcc) compared rest (hcp).
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ژورنال
عنوان ژورنال: Earth and Planetary Science Letters
سال: 2022
ISSN: ['1385-013X', '0012-821X']
DOI: https://doi.org/10.1016/j.epsl.2022.117688