Rotation of vertically oriented objects during earthquakes
Rotation of vertically oriented objects during earthquakes
复制标题
地震期间垂直方向物体的旋转
作者：
K. Hinzen
垂直方向的物体，如墓碑，纪念碑，柱子和石灯笼，经常被观察到在地震地面运动期间移动和旋转。这种观测通常限于中震区。近场旋转地面运动分量是否是必要的，除了纯平移运动来解释所观察到的旋转是一个悬而未决的问题。我们总结了1925年至2009年期间7次地震的旋转数据，并对垂直方向的物体进行了模拟和数值旋转测试。在滑台上的大理石块的自由摇摆运动受到垂直于摇摆运动方向的脉冲的干扰。当脉冲足够强并且发生在“正确”时刻时，它会引起块的显著旋转。自由摇摆块的数值实验表明，由正交于摇摆轴施加的摆线加速度脉冲引发竖直块旋转取决于脉冲的幅度及其与摇摆周期的相位关系。当脉冲加速度超过引起静止块摇摆所需的阈值时，旋转发生，并且摇摆块接近其平衡位置。在2009年拉奎拉地震期间测量的全三维强震信号下进行的块体实验证实了分析地面运动测试的观测结果。一个整体块体和两个堆叠块体的旋转行为存在显著差异。
Vertically oriented objects, such as tombstones, monuments, columns, and stone lanterns, are often observed to shift and rotate during earthquake ground motion. Such observations are usually limited to the mesoseismal zone. Whether near-field rotational ground motion components are necessary in addition to pure translational movements to explain the observed rotations is an open question. We summarize rotation data from seven earthquakes between 1925 and 2009 and perform analog and numeric rotation testing with vertically oriented objects. The free-rocking motion of a marble block on a sliding table is disturbed by a pulse in the direction orthogonal to the rocking motion. When the impulse is sufficiently strong and occurs at the ‘right’ moment, it induces significant rotation of the block. Numeric experiments of a free-rocking block show that the initiation of vertical block rotation by a cycloidal acceleration pulse applied orthogonal to the rocking axis depends on the amplitude of the pulse and its phase relation to the rocking cycle. Rotation occurs when the pulse acceleration exceeds the threshold necessary to provoke rocking of a resting block, and the rocking block approaches its equilibrium position. Experiments with blocks subjected to full 3D strong motion signals measured during the 2009 L’Aquila earthquake confirm the observations from the tests with analytic ground motions. Significant differences in the rotational behavior of a monolithic block and two stacked blocks exist.
影响因子：
1.6
作者：
Bernauer, Felix;Wassermann, Joachim;Igel, Heiner
通讯作者：
Igel, Heiner
地震顶柱对地面运动和几何形状微小变化的敏感性
DOI：
10.1560/ijes.58.3-4.309
发表时间：
2009
期刊：
Israel Journal of Earth Sciences
影响因子：
--
作者：
Hinzen
通讯作者：
Hinzen