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A method for the separation of source and site effects and the apparent Q structure from strong motion data
Author(s) -
Petukhin Anatoly,
Irikura Kojiro
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 - 10.1029/2000gl011561
Subject(s) - inversion (geology) , block (permutation group theory) , variable (mathematics) , constant (computer programming) , separation (statistics) , spectral line , motion (physics) , computational physics , physics , geometry , geodesy , geology , mathematics , algorithm , mathematical analysis , computer science , statistics , seismology , classical mechanics , astronomy , tectonics , programming language
A new/modified technique for the separation of source, path and site effects from strong motion records is proposed. To do this we made two extensions of the method developed in [ Iwata and Irikura, 1988]. (1) We allow the Q ‐value to be variable with depth and subregion in a block model of the medium with constant Q in each block. Path lengths within blocks are calculated using ray approximation. (2) To estimate the absolute site effect at reference station (and source effects respectively) we can use the H/V spectral ratio method for the S‐wave group to determine the spectral correction at the reference station. Our new method was applied to a set of KNET data in the Tohoku area of Japan. Preliminary results of Q structure inversion show that Q has minor variations with depth, and slightly decreases in the deepest layer. Source effects clearly show the existence of f max phenomena ( f max =13Hz).