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至今国内外对地震动的三个平动分量已进行了较为充分的研究,但对含三个转动分量的六分量地震动记录的研究尚显不足.利用我国台湾东部HGSD台站在2007-2008年间的52次地震的六分量地震动的实测记录,分析了平动分量中竖向地震动与水平向地震动峰值比和转动分量中扭转地震动与摇摆地震动的角速度峰值比随震中距的变化.在此基础上,选择一组典型的含三个转动分量的六分量地震动记录,采用正交化HHT(Hilbert-Huang Transform)法对各分量的时频特征进行了对比分析.结果表明:在近震区域存在较大的竖向地震动,扭转分量的角速度峰值总体上大于摇摆分量的角速度峰值;各个分量上的能量分布存在差异,转动分量的卓越频带较平动分量宽;转动分量中的摇摆分量较扭转分量含有更多的高频成分.
Up to now, the three translational components of earthquakes at home and abroad have been studied more fully, but there is still not enough research on the six-component ground motion records with three rotational components.Using the HGSD stations in the eastern part of Taiwan in 2007-2008 Sixty-two ground-based earthquakes in 52 earthquakes during the year were measured and recorded. The peak-to-earth ratio of the angular velocity of the torsional earthquakes to the earthquakes in the vertical motion and the horizontal motion was analyzed. Based on this, a set of typical six-component ground motion records with three rotating components are selected, and the time-frequency characteristics of each component are analyzed by using Hilbert-Huang Transform : There is a large vertical ground motion in the near-earthquake region. The peak angular velocity of the torsional component is generally larger than the peak angular velocity of the rocking component. The energy distribution of each component is different, and the excellent frequency band of the rotational component is wider than the translational component. The swing component contains more high frequency components than the twist component.