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Indexed by:期刊论文

Date of Publication:2013-12-01

Journal:EARTHQUAKE ENGINEERING AND ENGINEERING VIBRATION

Included Journals:SCIE、Scopus

Volume:12

Issue:4

Page Number:503-518

ISSN No.:1671-3664

Key Words:near-fault ground motions; fractal property; box-counting dimension; frequency content indicators; correlation analysis

Abstract:This study explores the irregularity and complexity of strong earthquake ground motions from the perspective of fractal geometry, and constructs a relation with the frequency content of the ground motions. The box-counting fractal dimensions and five representative period parameters of near-fault ground motions from the Chi-Chi and Northridge earthquakes are calculated and compared. Numerical results indicate that the acceleration and velocity time histories of ground motions present the statistical fractal property, and the dominant pulses of near-fault ground motions have a significant influence on their box dimensions and periods. Further, the average box dimension of near-fault impulsive ground motions is smaller, and their irregular degree of wave forms is lower. Moreover, the box dimensions of ground motions reflect their frequency properties to a large extent, and can be regarded as an alternative indicator to represent their frequency content. Finally, the box dimension D of the acceleration histories shows a considerably negative correlation with the mean period T (m). Meanwhile, the box dimension of the velocity histories D (vel) is negatively correlated with the characteristic period T (c) and improved characteristic period T (gi).