摘要
Using near-fault strong motions from Wenchuan earthquake recorded by the National Strong Motion Observation Network System of China as database, non-stationary characteristics of amplitude and frequency content of strong motions from 2008 Wenchuan earthquake are investigated, and the reason for intense non-stationary characteristics of near-fault strong motions are analyzed. According to this study, non-stationary characteristics of near-fault strong motions are strongly affected by fault rupture mechanism, location of strong motion stations and site conditions. A noticeable phenomenon is shown that the period of recorded velocity pulse in Wenchuan earthquake is much larger than the Chi-Chi and Kobe earthquake, as a result of a much larger magnitude for this event.