# Determination of the Probabilities of Landslide Events—A Case Study of Bhutan

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## Abstract

**:**

## 1. Introduction

## 2. Study Area

## 3. Methodology

#### 3.1. One-Dimensional Bayesian Probability

_{R,}number of landslide events being M

_{A}, number of precipitation events of degree B be M

_{B}and the number of precipitation events leading to slide initiation be M

_{(B|A)}, then Equation (1) reduces to the computation of the following frequencies:

_{A}/M

_{R}

_{B}/M

_{R}

_{(B|A)}/M

_{A}

#### 3.2. Two-Dimensional Bayesian Probability

## 4. Data

## 5. Results

## 6. Conclusions

- The use of a probabilistic approach can be a better approach than empirical thresholds as the latter provides a single value of a specific rainfall parameter for landslide incidences.
- The use of two-dimensional probability for determining probabilities for landslide events is better as compared to one-dimensional as the latter depicts that a single rainfall parameter may not be a significant factor to trigger landslides.
- The validation of the thresholds for event rainfall parameter depicts that the model has an accuracy of 57%. However, with the addition of more landslide records and temporal rainfall data, the accuracy will improve. The use of such technique would help in setting up an operational early warning system and help in landslide mitigation.

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

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**Figure 3.**Box and whisker plots showing the annual variation of monthly rainfall measures in the study area for the 11-year period 2004–2014.

**Figure 4.**One-dimensional probability considering (

**a**,

**b**) Event Rainfall (

**c**,

**d**) Rainfall Duration (

**e**,

**f**) Rainfall Intensity for Chukha region.

**Figure 5.**Two-dimensional probability considering rainfall intensity and rainfall duration parameters.

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**MDPI and ACS Style**

Sarkar, R.; Dorji, K.
Determination of the Probabilities of Landslide Events—A Case Study of Bhutan. *Hydrology* **2019**, *6*, 52.
https://doi.org/10.3390/hydrology6020052

**AMA Style**

Sarkar R, Dorji K.
Determination of the Probabilities of Landslide Events—A Case Study of Bhutan. *Hydrology*. 2019; 6(2):52.
https://doi.org/10.3390/hydrology6020052

**Chicago/Turabian Style**

Sarkar, Raju, and Kelzang Dorji.
2019. "Determination of the Probabilities of Landslide Events—A Case Study of Bhutan" *Hydrology* 6, no. 2: 52.
https://doi.org/10.3390/hydrology6020052