Morphological and geometric features are significant in landslide mobility characterization, landslide volume estimation, and the analysis of relevant movement mechanisms and hazard assessment. To better understand the geometric and kinematic characteristics of landslides triggered by the 2018 Palu earthquake, we analyzed the shape, geometry, and mobility characteristics of approximately 15,600 coseismic landslides with areas greater than 100 m2, based on the 8-m resolution Digital Elevation Model Nasional (DEMNAS) data. We assessed the correlation between landslides and geomorphologic parameters and ground motion. The results indicate that the length (L) and height (H) of the landslides logarithmically increase with the increase of landslide area. The length-to-height ratio (H/L) roughly shows a decline trend with the increase of landslide area, indicating a negative correlation between landslide mobility and landslide area. More than 98.6% of the landslides exhibit an ellipticity index (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="10346_2025_2601_Article_IEq1.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">${e}_{L}$</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>e</mi> <mi>L</mi> </msub> </math></EquationSource> </InlineEquation>) greater than 0.5, indicating that most of the landslides triggered by the Palu earthquake are elliptical in shape. In addition, the majority of the landslides are longitudinal landslides, followed by elongated landslides. Overall, ground motion is not the main factor affecting the H/L value compared to topographical factors. Particularly, the gradient information is the primary factor controlling the H/L of landslide. Landslides that occurred in sedimentary rocks exhibit higher mobility compared to those in plutonic and metamorphic rocks. Finally, we quantitatively compared the geometric features and mobility of the Palu earthquake-induced landslides with those triggered by other major seismic events. The results show that compared to events such as the 2010 Haiti earthquake, 2013 Minxian earthquake, and two earthquakes in Lefkada, the Palu earthquake-induced landslides have a longer travel distance under the same height condition. This difference can be attributed to the specific seismic characteristics of the Palu region.

Geometry and mobility characteristics of landslides triggered by the 2018 Mw 7.5 Palu earthquake in Indonesia

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发表日期：

2025年8月8日

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Siyuan Ma,
Xiaoyi Shao,
Chong Xu,
Pengfei Niu

摘要

Morphological and geometric features are significant in landslide mobility characterization, landslide volume estimation, and the analysis of relevant movement mechanisms and hazard assessment. To better understand the geometric and kinematic characteristics of landslides triggered by the 2018 Palu earthquake, we analyzed the shape, geometry, and mobility characteristics of approximately 15,600 coseismic landslides with areas greater than 100 m², based on the 8-m resolution Digital Elevation Model Nasional (DEMNAS) data. We assessed the correlation between landslides and geomorphologic parameters and ground motion. The results indicate that the length (L) and height (H) of the landslides logarithmically increase with the increase of landslide area. The length-to-height ratio (H/L) roughly shows a decline trend with the increase of landslide area, indicating a negative correlation between landslide mobility and landslide area. More than 98.6% of the landslides exhibit an ellipticity index ( ${e}_{L}$ $e_{L}$ ) greater than 0.5, indicating that most of the landslides triggered by the Palu earthquake are elliptical in shape. In addition, the majority of the landslides are longitudinal landslides, followed by elongated landslides. Overall, ground motion is not the main factor affecting the H/L value compared to topographical factors. Particularly, the gradient information is the primary factor controlling the H/L of landslide. Landslides that occurred in sedimentary rocks exhibit higher mobility compared to those in plutonic and metamorphic rocks. Finally, we quantitatively compared the geometric features and mobility of the Palu earthquake-induced landslides with those triggered by other major seismic events. The results show that compared to events such as the 2010 Haiti earthquake, 2013 Minxian earthquake, and two earthquakes in Lefkada, the Palu earthquake-induced landslides have a longer travel distance under the same height condition. This difference can be attributed to the specific seismic characteristics of the Palu region.