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The Fragmented Death of the Farallon Plate
Author(s) -
Hawley William B.,
Allen Richard M.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl083437
Subject(s) - geology , subduction , plate tectonics , trench , convergent boundary , pacific plate , seismology , ridge , north american plate , oceanic crust , submarine pipeline , mid ocean ridge , paleontology , oceanography , tectonics , chemistry , organic chemistry , layer (electronics)
The processes that accompany the death of an oceanic plate, as a ridge nears a trench, remain enigmatic. How the plate might reorganize, fragment, and eventually be captured by one of the bounding plates are among the unresolved details. We present a tomographic model of the Pacific Northwest from onshore and offshore seismic data that reveals a hole in the subducted Juan de Fuca plate. We suggest that this hole is the result of a tear along a preexisting zone of weakness, is causing volcanism on the North American plate, and is causing deformation in the Juan de Fuca plate offshore. We propose that in the final stages of an oceanic plate's life, deformation on the surface can be driven by deeper dynamics and that the fragmentation and the eventual capture of oceanic plate fragments may be governed by a process that operates from the bottom up.