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Seismic interferometry using non‐volcanic tremor in Cascadia
Author(s) -
Chaput J. A.,
Bostock M. G.
Publication year - 2007
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 - 10.1029/2007gl028987
Subject(s) - geology , seismology , subduction , seismic interferometry , interferometry , episodic tremor and slip , volcano , transect , noise (video) , reflection (computer programming) , arrival time , seismic array , geodesy , optics , tectonics , physics , oceanography , engineering , artificial intelligence , computer science , transport engineering , image (mathematics) , programming language
Seismic interferometry to date has focussed on surface waves, due to paucity of deep, high‐frequency noise sources. Here, we investigate use of non‐volcanic tremor on the Cascadia subduction zone as a noise source to recover scattered body‐wave contributions to the Green's function. Tremor data for 2004–2005 recorded at Polaris‐BC stations TWKB, MGCB and LZB were filtered and cross‐correlated. TWKB and MGCB correlations generate a highly reproducible arrival at 4.5 s for combinations of vertical with radial or transverse components. TWKB and LZB correlations are less reproducible, but yield a strong arrival at 3.5 s for 2005. Upon consideration of source/receiver geometry, polarity and timing, we interpret these arrivals to represent reflection‐conversions. Arrival times imply that these signals originate at depths between 9 and 12 km, coincident with an interval of strong reflectivity imaged in the 1987 Lithoprobe Southern Cordillera transect.