Visualisation of active normal fault scarps in the Apennines, Italy: A key to assessment of tectonic strain release and earthquake rupture
Visualisation of active normal fault scarps in the Apennines, Italy: A key to assessment of tectonic strain release and earthquake rupture
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意大利亚平宁山脉活动正断层陡坎的可视化：评估构造应变释放和地震破裂的关键
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发表时间：
2008
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通讯作者：
G. Roberts
中科院分区：
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作者：
G. Roberts
在意大利亚平宁山脉，活动的正断层陡坎偏移了12-18 ka的地貌，这些断层陡坎已被绘制成谷歌地球，以提供负责构造应变释放和地震破裂的结构的精确位置。末次盛冰期（12-18 ka）结束时的气候变化使侵蚀和沉积速率降低到临界阈值以下，从而使地表破裂至古地震产生的位移得以保留。由此产生的断层陡坎记录了多次地震引起的地表位移，可以确定断层滑动速率的空间变化，这是一个关键参数，用于评估地貌学记录的长期应变释放（104年）与地震目录和大地测量记录的短期应变释放（102-3年）之间的关系。断层滑动的空间变化发生在几十公里的尺度上，而断层崖的偏移量<20-40米，其地貌表现只能在空间分辨率接近米级的地形图像上可视化。因此，到目前为止，围绕陡坎的确切位置的争论至少部分是由于可视化详细的地貌特征及其区域变化的问题。在谷歌地球中提供完整的SPOT图像覆盖范围和地形，使得在实地考察期间访问的各个悬崖能够在一个易于访问的界面上以区域规模可视化。最后，利用这些结果对构造应变释放和地震破裂进行了评价。
Active normal fault scarps that offset 12-18 ka landforms in the Apennines, Italy, have been mapped into Google Earth to provide precise locations for structures responsible for tectonic strain release and earthquake rupture. Climate change at the end of the last glacial maximum (12-18 ka) reduced erosion and sedimentation rates below a critical threshold allowing preservation of displacements produced by surface ruptures to palaeoearthquakes. The resultant fault scarps, which record the surface displacements from multiple earthquakes, allow determination of the spatial variation in the rates of fault slip, a parameter critical to assessment of how long-term strain release recorded in the geomorphology (104 years) relates to short-term strain release recorded by earthquake catalogues and geodesy (102-3 years). Spatial variation in fault slip occurs at a scale of tens of kilometres, whilst fault scarps have offsets of <20-40 metres and a geomorphic expression that can only be visualised on topographic images with spatial resolution approaching the metre-scale. Thus, until now, debate has surrounded the exact positions of scarps at least in part due to problems of visualising both the detailed geomorphic features and their regional variation. Provision of complete SPOT image coverage and topography within Google Earth allows individual scarps visited during fieldwork to be visualised at a regional scale within an easily-accessible interface. The resultant maps are used to comment on tectonic strain release and earthquake rupture.