Effect of rock weathering, clay mineralogy, and geological structures in the formation of large landslide, a case study from Dumre Besei landslide, Lesser Himalaya Nepal

Regmi, Amar Deep; Yoshida, Kohki; Dhital, Megh Raj; Devkota, Krishna Chandra

doi:10.1007/s10346-011-0311-7

Cited by 95 publications

(29 citation statements)

References 32 publications

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“…Past studies have focused on simulating various situations by modifying variables in spatial models [24][25][26]. The measures should also consider general adaptation plans to deal with climate change.…”

Section: The Effect Of Adaptationmentioning

confidence: 99%

Assessing the Cost of Damage and Effect of Adaptation to Landslides Considering Climate Change

2018

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Abstract:The amount of damage caused by landslides has increased due to climate change. Adaptation plans are required to help cope with landslides in order to reduce the extent of the damage. Landslide hazard analysis can help create adaptation plans. Analyzing the cost of damage of and the effect of adaptation to landslides is an effective way to support decision makers. The cost of damage is calculated using the costs of damage incurred in residential and transportation areas in the past, based on data from annual reports. Spatial distribution models are used to analyze landslide hazard areas in the present and the future. Future or potential landslide hazards are estimated by using climate change scenarios through representative concentration pathways. The effects of adaptation measures are assessed using modified variables and a cost-benefit analysis. The uncertainty of the cost of damage is considered using average, minimum, and maximum values. As a result, the methods used to estimate future costs of damage are developed, and the effects of adaptation are analyzed. The future cost of damage is calculated for every climate change scenario. The effect of adaptation are analyzed and areas with a reduced risk of landslides are identified, reducing the cost of damage and adaptation costs, as well as the costs and benefits of adaptation measures. Improving soil drainage is the most effective measure among the four measures analyzed. This study can help estimate future costs of damage and analyze the effect of adaptation in creating effective adaptation plans.

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Section: The Effect Of Adaptationmentioning

confidence: 99%

Assessing the Cost of Damage and Effect of Adaptation to Landslides Considering Climate Change

2018

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“…Rainfall and Earthquakes are main triggering factor for mass movements [3] [4] [5] [6], however the rock type, type of bedrock, type of cover material, geotechnical and hydrogeological properties, land use, slope gradient, slope shape, and so on can be considered as contributory other contributory factors [3] [7] [8] [9] [10]. Sri Lanka is located in earthquake free zone [11] Therefore in Sri Lankan contest, rainfall can be considered as a main landslide triggering factor.…”

Section: Introductionmentioning

confidence: 99%

A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

Perera¹,

Jayawardana²,

Jayasinghe³

2017

GEP

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Mass movement in Sri Lanka is mainly triggered by heavy rainfall. International literature is rich of works defining rainfall intensity-duration models to identify the rainfall threshold for various types of Mass movement. However, studies have not focused to establish a relationship between intensity and duration of rainfall in Sri Lanka. Therefore, this study focused to establish rainfall intensity-duration models to identify the rainfall threshold for mass movements in Badulla district in Sri Lanka, where forty four (44) rainfall events that resulted in same number of landslides during the last three decades were considered. Results indicate the rainfall threshold relationship fits to the log linear model of the exponential function, I = α·D −β . The constructed I-D curve revealed that short duration (<2 h) and high-intensity (>54 mm/h) in rainfall events can potentially trigger the landslide. However, long-duration (>8 h) and low-intensity (<25 mm/h) in rainfall events may also trigger mass movements in Badulla. As per the results, most mass movements occur during northeast monsoons and inter-monsoons. In general, higher mean rainfall intensities trigger the debris flows, while long-duration rainfall events can trigger both landslides and debris flow. When compared to Sri Lankan mass movements triggering threshold intensities are fairly higher than the global threshold values. It confirms that within Badulla, mass movements are triggered by very high intense and/or long duration rainfalls events only. Further, time series analysis of the rainfall events shows an upward trend of extreme rainfall events, which increased landslide occurring frequency in last six (6) years.

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“…However, there exists only very few literature from Nepal focusing in the role of rock weathering and geological structures in landslide formation. Regmi et al (2012) reported that there is a considerable effect of rock weathering and geological structures in the formation of large landslides. It is essential to make more rigorous studies in this aspect to get accurate information regarding the relationship between rock weathering and geological structures in landslide formation in the Himalaya.…”

Section: Introductionmentioning

confidence: 99%

The relationship between geology and rock weathering on the rock instability along Mugling–Narayanghat road corridor, Central Nepal Himalaya

Regmi

Yoshida

Nagata³

et al. 2012

Nat Hazards

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The present study was conducted along the Mugling-Narayanghat road section and its surrounding region that is most affected by landslide and related mass-movement phenomena. The main rock types in the study area are limestone, dolomite, slate, phyllite, quartzite and amphibolites of Lesser Himalaya, sandstone, mudstone and conglomerates of Siwaliks and Holocene Deposits. Due to the important role of geology and rock weathering in the instabilities, an attempt has been made to understand the relationship between these phenomena. Consequently, landslides of the road section and its surrounding region have been assessed using remote sensing, Geographical information systems and multiple field visits. A landslide inventory map was prepared and comprising 275 landslides. Nine landslides representing the whole area were selected for detailed studies. Field surveys, integrated with laboratory tests, were used as the main criteria for determining the weathering zones in the landslide area. From the overall study, it is seen that large and complex landslides are related to deep rock weathering followed by the intervention of geological structures as faults, joints and fractures. Rotational types of landslides are observed in highly weathered rocks, where the dip direction of the foliation plane together with the rock weathering plays a principle role. Shallow landslides are developed in the slope covered by residual soil or colluviums. The rock is rather fresh below these covers. Some shallow landslides (rock topples) are related to the attitude of the foliation plane and are generally observed in fresh rocks. Debris slides and debris flows occur in colluviums or residual soil-covered slopes. In few instances, they are also related to the rock fall occurring at higher slopes.The materials from the rock fall are mixed with the colluviums and other materials lying on the slope downhill and flow as debris flow. Rock falls are mainly related to the joint pattern and the slope angle. They are found in less-weathered rocks. From all these, it is concluded that the rock weathering followed by geological structures has prominent role in the rock slope instability along Mugling-Narayanghat road section and its surrounding regions.

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Effect of rock weathering, clay mineralogy, and geological structures in the formation of large landslide, a case study from Dumre Besei landslide, Lesser Himalaya Nepal

Cited by 95 publications

References 32 publications

Assessing the Cost of Damage and Effect of Adaptation to Landslides Considering Climate Change

Assessing the Cost of Damage and Effect of Adaptation to Landslides Considering Climate Change

A Rainfall Intensity-Duration Threshold for Mass Movement in Badulla, Sri Lanka

The relationship between geology and rock weathering on the rock instability along Mugling–Narayanghat road corridor, Central Nepal Himalaya

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