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Characteristics of 3‐dimensional earthquake ground motions
Author(s) -
Penzien Joseph,
Watabe Makoto
Publication year - 1974
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290030407
Subject(s) - principal component analysis , principal axis theorem , ground motion , principal stress , epicenter , geometry , set (abstract data type) , geodesy , geology , transformation (genetics) , mathematics , mathematical analysis , seismology , statistics , computer science , biochemistry , chemistry , cauchy stress tensor , gene , programming language
Abstract An orthogonal set of principal axes is defined for earthquake ground motions along which the component variances have maximum, minimum and intermediate values and the covariances equal zero. Corresponding axes are defined which yield maximum values for the covariances. The orthogonal transformations involved are identical in form to those used in the transformation of stress. Examination of real accelerograms reveals that the major principal axis points in the general direction of the epicentre and the minor principal axis is nearly vertical. It is concluded that artificially generated components of ground motion need not be correlated statistically provided they are directed along a set of principal axes.