Open AccessImaging the seismic lithosphere‐asthenosphere boundary of the oceanic plate
Author(s) -
Kumar Prakash,
Kawakatsu Hitoshi
Publication year - 2011
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2010gc003358
Subject(s) - geology , asthenosphere , lithosphere , plate tectonics , geodynamics , convergent boundary , low velocity zone , geophysics , oceanic crust , subduction , seismology , mantle (geology) , tectonics , seismic tomography
The seismic lithosphere‐asthenosphere boundary (LAB) or G discontinuity, a seismologically characterized abrupt drop in wave speed in the uppermost mantle, is one of the key issues in current geodynamics. Although plate tectonics started as a theory for the ocean, reports on LAB for normal oceanic regions are scarce due to paucity of seismic data, and whether or not the oceanic LAB grows with age is the key issue to be resolved. We conduct a systematic survey for the oceanic LAB using S ‐to‐ p converted seismic waves along three margins of oceanic plates whose crustal age ranges from ∼10 Myr to ∼130 Myr, and we observe laterally continuous oceanic LAB images. The thickness of the oceanic plate estimated from LABs increases with the plate age, though scattered, suggesting that the evolution of oceanic lithosphere is predominantly governed by temperature and that the oceanic seismic LAB represents a boundary that grows with age.