Hierarchical Cluster Analysis of Dense GPS Data and Examination of the Nature of the Clusters Associated With Regional Tectonics in Taiwan
Hierarchical Cluster Analysis of Dense GPS Data and Examination of the Nature of the Clusters Associated With Regional Tectonics in Taiwan
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DOI：
10.1029/2018jb016995
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发表时间：
2019-05
期刊：
影响因子：
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通讯作者：
A. Takahashi;M. Hashimoto;Jyr‐Ching Hu;Koh Takeuchi;M. Tsai;Y. Fukahata
中科院分区：
文献类型：
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作者：
A. Takahashi;M. Hashimoto;Jyr‐Ching Hu;Koh Takeuchi;M. Tsai;Y. Fukahata
吕宋火山弧的碰撞是台湾岛形成的主要原因。此外，台湾海峡北港基底隆起的凹陷和冲绳海槽的弧后扩张是造成台湾地区构造特征的主要原因。活动构造界线的识别对于了解台湾的新构造运动具有重要意义。采用层次聚类方法对台湾地区全球定位系统(GPS)水平速度数据进行了分析。我们还开发了一种引入信息熵的统计方案来定量评估所获得的簇边界的模糊性，这使得我们能够区分可信的不连续。用树状图表示的层次表示表明了该地区构造源区的相对重要性。出现在较高层次的主要星系团，很可能代表主要的构造特征，如台湾西南部的纵谷断裂和侧向挤压。处于较低层级的那些表明与活动断层等局部地质结构有关的速度不连续。例如，通过这种分析，在没有利用地质信息的情况下，确定了台湾东部近海和台湾南部的边界。除了识别这些清晰的构造界线外，我们的统计聚类评估还显示，沿海平原和西部山麓存在模糊的簇边界，反映了台湾西部的连续变形。
Collision of the Luzon Volcanic Arc is the primary causative factor behind the creation of Taiwan Island. Additionally, the indention of the Peikang basement highs in the Taiwan Strait and the back arc spreading of the Okinawa Trough are responsible for the characteristic tectonics in Taiwan. Identification of active tectonic boundaries is important for understanding neotectonics in Taiwan. We analyzed Global Positioning System (GPS) horizontal velocity data in Taiwan with a hierarchical cluster analysis method. We also developed a statistical scheme introducing information entropy to quantitatively assess the fuzziness of the obtained cluster boundaries, which enables us to distinguish a trustworthy discontinuity. The hierarchical representation, which is expressed by a dendrogram, suggests the relative importance of tectonic sources in this region. The major clusters, which appear at higher hierarchy, are likely to represent major tectonic features such as the Longitudinal Valley fault and lateral extrusion in southwest Taiwan. Those at lower hierarchy suggest velocity discontinuities associated with local geological structures such as active faults. For example, boundaries in east offshore Taiwan and southern Taiwan are identified without using geological information by this analysis. In addition to the identification of these clear tectonic boundaries, our statistical cluster assessment shows the existence of fuzzy cluster boundaries along the Coastal Plain and the Western Foothills, reflecting continuum deformation in west Taiwan.