Premium
Evidence for both crustal and mantle earthquakes in the subducting Juan de Fuca plate
Author(s) -
Cassidy John F.,
Waldhauser Felix
Publication year - 2003
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 - 10.1029/2002gl015511
Subject(s) - geology , seismology , induced seismicity , receiver function , mantle (geology) , crust , intraplate earthquake , subduction , oceanic crust , geophysics , tectonics , lithosphere
We investigate the relationship between high‐precision hypocentres in the subducting Juan de Fuca plate beneath southwest British Columbia, and the velocity structure from receiver function analysis and reflection seismic data. 108 earthquakes at depths of 40 to 65 km were relocated using a double‐difference algorithm to obtain precise earthquake locations. Correlation of the relocated seismicity with structural information shows a concentration of earthquakes near the top of the subducting oceanic crust, and a deeper layer of seismicity in the uppermost mantle of the subducting Juan de Fuca plate. The strong correlation of the seismicity with the structure of the subducting plate suggests that seismic failure is caused by changes in mechanical strength within the plate, supporting the hypotheses that phase transformations and thermal‐petrological conditions play an important role in the seismogenesis of double‐seismic zones.