2004年苏门答腊-安达曼地震的范围,持续时间和速度,由Hi-Net阵列成像
Miaki Ishii1, Peter M Shearer, Heidi Houston
1Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, IGPP 0225, University of California San Diego, La Jolla, California 92093, USA. mishii@ucsd.edu
Nature
|May 24, 2005
概括
科学家们开发了一种新方法,可以近乎实时地图像地震破裂的进展. 这项分析揭示了2004年苏门答腊-安达曼地震.
科学领域:
- 地震地震学地震学
- 地质物理学 地质物理学
- 构造学 构造学 构造学 构造学
背景情况:
- 2004年苏门答腊-安达曼地震是一次具有重大破坏潜力的重大地震事件.
- 准确估计地震强度和断裂特征对于了解地震危险至关重要.
- 此前对这一事件的规模估计有所不同,这突显了需要改进分析技术的需要.
研究的目的:
- 引入一种用于直接地震破裂成像的新方法.
- 为了确定2004年苏门答腊-安达曼地震破裂的时空演变.
- 为了完善这一重大地震的时刻大小估计和断裂特征.
主要方法:
- 利用日本的Hi-Net地震阵列作为一个大孔天线.
- 采用首次到达的压缩波来监测高频辐射方向.
- 开发了一种技术,可以在地震发生后30分钟内直接对地震破裂的进展进行成像.
主要成果:
- 断裂向北传播,遍及整个1300公里的余震区域.
- 断裂速度被确定为大约2.8公里/秒,持续时间为8分钟.
- 证实了苏门答腊-安达曼地震的时刻强度约为9.3.
- 确定破裂是有史以来记录的最长的破裂,无论是持续时间还是范围.
结论:
- 新的成像方法提供了对地震断裂动态的快速和详细的见解.
- 苏门答腊-安达曼地震的断裂特征与9.3级的瞬间强度一致.
- 这一事件代表了有记录的地震历史上前所未有的破裂规模.
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