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The 2005 Kashmir earthquake has triggered widespread landslides in the Himalayan mountains in northern Pakistan and surrounding areas, some of which are active and are still posing a significant risk. Landslides triggered by the 2005 Kashmir earthquake are extensively studied; nevertheless, spatio-temporal landslide susceptibility assessment is lacking. This can be partially attributed to the limited availability of high temporal resolution remote sensing data. We present a semi-automated technique to use the Sentinel-2 MSI data for co-seismic landslide detection, landslide activities monitoring, spatio-temporal change detection, and spatio-temporal susceptibility mapping. Time series Sentinel-2 MSI images for the period of 2016–2021 and ALOS PALSAR DEM are used for semi-automated landslide inventory map development and temporal change analysis. Spectral information combined with topographical, contextual, textural, and morphological characteristics of the landslide in Sentinel-2 images is applied for landslide detection. Subsequently, spatio-temporal landslide susceptibility maps are developed utilizing the weight of evidence statistical modeling with seven causative factors, i.e., elevation, slope, geology, aspect, distance to fault, distance to roads, and distance to streams. The results reveal that landslide occurrence increased from 2016 to 2021 and that the coverage of areas of relatively high susceptibility has increased in the study area. [ABSTRACT FROM AUTHOR]

Considering the ever-increasing landslide incidences in Indian Himalayas, a methodology has been presented to assess the risk to buildings constructed in the landslide-prone areas. Since landslide is a dynamic phenomenon, an inter-disciplinary approach is required for the assessment of elements at risk (buildings in this case). Therefore, a novel remote sensing and GIS-based semi-quantitative technique has been developed by integrating the concepts of landslide susceptibility zonation (LSZ), physical vulnerability (PV) and the proximity (Prox) of buildings from the influence zone (i.e. LSZ and drainage channels). In order to understand the acceptability of risk, the landslide risk (LR) has been categorized into three risk classes as class I (low risk), class II (moderate risk) and class III (high risk). This study aims to develop a systematic and easy to adopt methodology for hilly terrains of India in a scenario of historical data scarcity and also in line with the codal provisions of the country as well as the geographical conditions. The developed methodology is implemented in a test site of Gopeshwar Township, Chamoli District Headquarter, Uttarakhand State of India, covering an area of 8.39 km2 situated in the upper Alaknanda valley. This study will be useful in increasing the safety aspects of the infrastructures and lives and also for strategic governance of developmental activities in the times ahead, especially in developing countries. [ABSTRACT FROM AUTHOR]

Garhwal Himalaya in northern India has emerged as one of the most prominent hot spots of landslide occurrences in the Himalaya mainly due to geological causes related to mountain building processes, steep topography and frequent occurrences of extreme precipitation events. As this region has many pilgrimage and tourist centres, it is visited by hundreds of thousands of people every year, and in the recent past, there has been rapid development to provide adequate roads and building infrastructure. Additionally, attempts are also made to harness hydropower by constructing tunnels, dams and reservoirs and thus altering vulnerable slopes at many places. As a result, the overall risk due to landslide hazards has increased many folds and, therefore, an attempt was made to assess landslide susceptibility using 'Weights of Evidence (WofE)', a well-known bivariate statistical modelling technique implemented in a much improved way using remote sensing and Geographic Information System. This methodology has dual advantage as it demonstrates how to derive critical parameters related to geology, geomorphology, slope, land use and most importantly temporal landslide distribution in one of the data scarce region of the world. Secondly, it allows to experiment with various combination of parameters to assess their cumulative effect on landslides. In total, 15 parameters related to geology, geomorphology, terrain, hydrology and anthropogenic factors and 2 different landslide inventories (prior to 2007 and 2008-2011) were prepared from high-resolution Indian remote sensing satellite data (Cartosat-1 and Resourcesat-1) and were validated by field investigation. Several combinations of parameters were carried out using WofE modelling, and finally using best combination of eight parameters, 76.5 % of overall landslides were predicted in 24 % of the total area susceptible to landslide occurrences. The study has highlighted that using such methodology landslide susceptibility assessment can be carried out in vast stretches of Himalaya in short time in order to assess the impact of development as well as climate change/variability. The resultant map can play a critical role in selecting areas for remedial measures for slope stabilisation as well planning for future development of the region. [ABSTRACT FROM AUTHOR]

In this study, landslide risk assessment for Izmir city (west Turkey) was carried out, and the environmental effects of landslides on further urban development were evaluated using geographical information systems and remote sensing techniques. For this purpose, two different data groups, namely conditioning and triggering data, were produced. With the help of conditioning data such as lithology, slope gradient, slope aspect, distance from roads, distance from faults and distance from drainage lines, a landslide susceptibility model was constructed by using logistic regression modelling approach. The accuracy assessment of the susceptibility map was carried out by the area under curvature (AUC) approach, and a 0.810 AUC value was obtained. This value shows that the map obtained is successful. Due to the fact that the study area is located in an active seismic region, earthquake data were considered as primary triggering factor contributing to landslide occurrence. In addition to this, precipitation data were also taken into account as a secondary triggering factor. Considering the susceptibility data and triggering factors, a landslide hazard index was obtained. Furthermore, using the Aster data, a land-cover map was produced with an overall kappa value of 0.94. From this map, settlement areas were extracted, and these extracted data were assessed as elements at risk in the study area. Next, a vulnerability index was created by using these data. Finally, the hazard index and the vulnerability index were combined, and a landslide risk map for Izmir city was obtained. Based on this final risk map, it was observed that especially south and north parts of the Izmir Bay, where urbanization is dense, are threatened to future landsliding. This result can be used for preliminary land use planning by local governmental authorities. [ABSTRACT FROM AUTHOR]

A method is presented to monitor the development of geomorphic hazard areas by overlaying time series of air photos in a digital image processing system. The present study deals with such hazards affecting an urban area, Villavicencio at the foot of the eastern Andes in Colombia. The relevant windows of the air photos are digitized by flat-bed scanning and then transformed geometrically to be overlain on SPOT panchromatic imagery where available. The 10 m resolution of the satellite imagery allows, in practice, sufficient detail to bring out thedifferences, which are a yardstick to monitor the development of thephenomenon over time. Where no SPOT panchromatic imagery is available, one of the photos may be taken as a reference; registration to a topographic base map is also possible. A development over time to the present hazardous situations can be read from the analyzed imagery. Air photo series dating back to 1937 are available for this research, in the context of a geomorphic hazards study currently undertaken in the eastern Colombian Andes front where it pushes against the Llanos Orientales. The mountain front is quite steep and high, and the contact with the plains is very abrupt. A thrust fault zone in which the rocks are strongly mylonitized, marks the eastern front. Villavicenciolies just below this zone, but its main access road has to cross it.The terrain is mostly made up of Mesozoic and Palaeozoic sedimentaryseries, with prominent black lutites; Tertiary sedimentaries are found in the foreland. All rocks are strongly folded and faulted. Precipitation is in the order of 3500-5500 mm per year. Records on river discharge events are scarce or absent. Seismic events are frequent in the area. This area is prone to strong and rapid geomorphic processes posing hazards to the inhabitants. The town of Villavicencio is the gateway to the Llanos Orientales. It is the major town for hundreds ofkilometres around, and a commercial, educational and health centre for the [ABSTRACT FROM AUTHOR]