Dispersion index of topographic surfaces

详细信息	查看全文 | 推荐本文 |

• 作者：Massimiliano Favalli ; Simone Tarquini ; ^{tarquini@pi.ingv.it} ; Alessandro Fornaciai ; Enzo Boschi
• 关键词：Dispersion index ; DEM ; Lava flow ; Geomorphic parameter ; Mount Etna
• 刊名：Geomorphology
• 出版年：2012
• 期刊代码：31_0169555x
• 类别：soc
• 出版时间：1 June, 2012
• 卷：153-154
• 期：Complete
• 页码：169-178
• 文件大小：4686 K

摘要

The dispersion index (d_蟽) of topography is introduced. This index is a geomorphic parameter which characterizes each point of topography with respect to the stability/instability of the steepest descent path (SDP) originating from it. The procedure for calculating d_蟽 is based on the assessment of SDP variations as the initial topography is also varied within a given elevation 螖h, while a length scale L defines the maximum extent of the SDP. As a result, d_蟽 can be derived for different ranges 螖h and different bandwidths L. Since at each point the gravitational force would direct a surface flow along the SDP, d_蟽 appears to have a strong influence on the behavior of gravity-driven mass flows, influencing local topographic widening, spreading or channelization. Considering Mount Etna (Italy) as a test case, we present maps of d_蟽 for 螖h = 3 m and L = 1, 2, 4 and 8 km, demonstrating also the relationship between the range 螖h = 3 m and Etnean lava flows. Focusing on the 2001 lava flow, we show that the presented maps of d_蟽, besides being a tool for viewing morphologies, have interesting applications for hazard assessment related to lava flows.