Mapping landslide susceptibility using data-driven methods

数据驱动方法在滑坡易发性评价中的应用

Science of The Total Environment, Volume 589, 1 July 2017, Pages 250-267

J.L. Zêzere, S. Pereira, R. Melo, S.C. Oliveira, R.A.C. Garcia

Abstract:Most epistemic uncertainty within data-driven landslide susceptibility assessment results from errors in landslide inventories, difficulty in identifying and mapping landslide causes and decisions related with the modelling procedure. In this work we evaluate and discuss differences observed on landslide susceptibility maps resulting from: (i) the selection of the statistical method; (ii) the selection of the terrain mapping unit; and (iii) the selection of the feature type to represent landslides in the model (polygon versus point). The work is performed in a single study area (Silveira Basin - 18.2 km2 - Lisbon Region, Portugal) using a unique database of geo-environmental landslide predisposing factors and an inventory of 82 shallow translational slides.The logistic regression, the discriminant analysis and two versions of the information value were used and we conclude that multivariate statistical methods perform better when computed over heterogeneous terrain units and should be selected to assess landslide susceptibility based on slope terrain units, geo-hydrological terrain units or census terrain units. However, evidence was found that the chosen terrain mapping unit can produce greater differences on final susceptibility results than those resulting from the chosen statistical method for modelling.

The landslide susceptibility should be assessed over grid cell terrain units whenever the spatial accuracy of landslide inventory is good. In addition, a single point per landslide proved to be efficient to generate accurate landslide susceptibility maps, providing the landslides are of small size, thus minimizing the possible existence of heterogeneities of predisposing factors within the landslide boundary.

Although during last years the ROC curves have been preferred to evaluate the susceptibility model's performance, evidence was found that the model with the highest AUC ROC is not necessarily the best landslide susceptibility model, namely when terrain mapping units are heterogeneous in size and reduced in number.

Landslide characterization using a multidisciplinary approach

基于多学科方法的滑坡特征化

Measurement, Volume 104, July 2017, Pages 294-301

Ernesto Ausilio, Paolo Zimmaro

Abstract: A large number of factors should be taken into account to understand landslide phenomena and to facilitate stabilization design especially for complex cases. In this paper the case history of the Gimigliano landslide in the Calabria region (southern Italy) is investigated by using a multidisciplinary combined-technique approach based on conventional geotechnical measurements and modern technologies. The first technique (with reference to inclinometer measurements) is usually affected by errors. Particular care is devoted to the data processing by using ad-hoc methodology to take these errors into account, with the purpose of ensuring a high reliability. For the second technique (electromagnetic sensing techniques and electrical resistivity tomography) convenient methodologies for data post-processing are used and herein presented. The combination of information taken from the different techniques allows the measurements obtained to be validated by conventional and modern approaches and the accuracy of each to be enhanced.

Tectonic control of complex slope failures in the Ameka River Valley (Lower Gibe Area, central Ethiopia): Implications for landslide formation

埃塞俄比亚中部Ameka河谷复合型边坡破坏的构造控制：滑坡成因探索

Geomorphology, Volume 288, 1 July 2017, Pages 175-187

Petr Kycl, Vladislav Rapprich, Kryštof Verner, Jan Novotný, Tomáš Hroch, Jan Mišurec, Habtamu Eshetu, Ezra Tadesse Haile, Leta Alemayehu, Tomasz Goslar

Abstract:Even though major faults represent important landslide controlling factors, the role the tectonic setting in actively spreading rifts plays in the development of large complex landslides is seldom discussed. The Ameka complex landslide area is located on the eastern scarp of the Gibe Gorge, approximately 45 km to the west of the Main Ethiopian Rift and 175 km to the southwest of Addis Ababa. Investigation of the complex landslide failures required a combination of satellite and airborne data-based geomorphology, geological field survey complemented with structural analysis, radiocarbon geochronology and vertical electric sounding. The obtained observations confirmed the multiphase evolution of the landslide area. We have documented that, apart from climatic and lithological conditions, the main triggering factor of the Ameka complex landslide is the tectonic development of this area. The ~ E–W extension along the ~ NNE–SSW trending Main Ethiopian Rift is associated with the formation of numerous parallel normal faults, such as the Gibe Gorge fault and the almost perpendicular scissor faults. The geometry of the slid blocks of coherent lithology have inherited the original tectonic framework, which suggests the crucial role tectonics play in the fragmentation of the compact rock-masses, and the origin and development of the Ameka complex landslide area. Similarly, the main scarps were also parallel to the principal tectonic features. The local tectonic framework is dominated by faults of the same orientation as the regional structures of the Main Ethiopian Rift. Such parallel tectonic frameworks display clear links between the extension of the Main Ethiopian Rift and the tectonic development of the landslide area. The Ameka complex landslide developed in several episodes over thousands of years. According to the radiocarbon data, the last of the larger displaced blocks (representing only 2% of the total area) most likely slid down in the seventh century AD. The main scarps, namely the high scarps in the western part, are unstable over the long term and toppling and falling-type slope movements can be expected here in the future.