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Intraplate earthquakes and a seismically defined lateral transition in the upper mantle
Author(s) -
Thybo H.,
Perchuć E.,
Zhou S.
Publication year - 2000
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 - 10.1029/2000gl011636
Subject(s) - intraplate earthquake , geology , lithosphere , seismology , crust , transition zone , mantle (geology) , shear (geology) , upper crust , geophysics , differential stress , deformation (meteorology) , tectonics , petrology , oceanography
We show that the lateral transition in the upper mantle between the cratonic central/eastern and the tectonically active western regions of North America is narrow and deep‐reaching by travel time analysis of Early Rise explosion seismic data. A concentration of enigmatic intraplate earthquakes coincides with the transition. Differential potential energy from density changes across the transition may generate a high compressional stress level which, locally, exceeds the shear strength of the lithosphere. The resultant deformation is ductile in most parts of the lithosphere, but in the brittle upper crust it explains the enigmatic intraplate earthquakes around the lateral transition in the upper mantle.