Investigation of Long-Period Ground Motion in the NorthridgeEarthquake of January 17, 1994.

1994 年 1 月 17 日北岭地震中长周期地面运动的调查。

• 批准号: 9413273
• 负责人: Wilfred Iwan
• 金额: $ 2.27万
• 依托单位: California Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-06-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9413273&HistoricalAwards=false
• 关键词: Investigation; Long; Period; Ground; Motion

9413273 Iwan The Northridge earthquake of January 17, 1994 yielded what may prove to be the most valuable set of strong motion data ever obtained from an earthquake. These data include the largest horizontal ground motion ever recorded. The damage associated with these large ground motions is well documented. In some of the near-field accelerograms, particularly the Sylmar station, there is evidence of a significant long period displacement pulse in the ground motion. The existence of such motion has recently been the subject of great concern as it relates to the design of base isolated and high-rise structures. These structures are particularly susceptible to large input displacements. There is a recognized need to better understand the nature of this long period motion and, ultimately, to be able to model and predict is occurrence. Present routine techniques for the processing of strong motion data tend to remove or distort the long-period information from recorded accelerograms. However, under a recent NSF exploratory grant, techniques have been developed to recover much of the long-period information in accelerograms. This is accomplished by nontraditional baseline correction and signal processing that is based on an improved understanding of the physics of the ground motion and the nature of the recording instruments. The techniques have been verified for ground motions from the Landers earthquake. The goal of this research program is to apply the recently developed data processing techniques to a suite of earthquake records from the Northridge earthquake. The ultimate goal is to provide a basis for guidelines that may be used to characterize the long-period content of earthquake motion for structural design. This exploratory investigation addresses the following questions: 1. What is the nature of the long period (displacement) content of ground motion from this type of thrust earthquake? 2. How does this vary with distance from th e epicenter and orientation with respect to the fault plain. 3. How is the long-period content (peak displacement) related to the short-period content (peak acceleration)? 4. What generalizations can be made to future events of this, or another, type? 5. Is there a correlation between the observed long-period ground motion and structural damage? The research is based on digital data obtained from the California Division of Mines and Geology and the U.S. Geological Survey. ***

9413273 IWAN 1994年1月17日的北龙地震产生了可能是从地震中获得的最有价值的一组强大运动数据。 这些数据包括有史以来最大的水平地面运动。 与这些大型地面运动相关的损坏已得到充分记录。 在某些近场加速度图，尤其是西尔玛站，有证据表明地面运动中有很大的长时间位移脉冲。 最近，这种运动的存在与基础隔离和高层结构的设计有关，因此引起了人们的关注。这些结构特别容易受到大型输入位移的影响。 有公认的需要更好地理解这一长期运动的性质，并最终能够建模和预测是发生的。 当前用于处理强运动数据的常规技术倾向于从记录的加速图中删除或扭曲长期周期信息。 但是，根据最近的NSF探索赠款，已经开发了用于恢复加速图中许多长期信息的技术。 这是通过非传统基线校正和信号处理来实现的，该基础是基于对地面运动物理和记录工具性质的理解的提高。这些技术已得到验证，从地震中进行了地震的地面运动。 该研究计划的目的是将最近开发的数据处理技术应用于诺斯里奇地震的一系列地震记录。 最终目标是为可能用于表征地震运动的长期周期含量的指南提供基础。 这项探索性研究解决了以下问题：1。从这种类型的推力地震中，地面运动的长时间（位移）内容的性质是什么？ 2。这与与断层平原相对于中心和方向的距离有何不同。 3。长期含量（峰位移）与短期含量（峰值加速度）有何关系？ 4。可以对此类型的未来事件进行哪些概括？ 5。观察到的长周期地面运动与结构损伤之间是否存在相关性？ 该研究基于从加利福尼亚矿山和地质科和美国地质调查局获得的数字数据。 ***