Geoinformatics approach to classifying landslide hazard in the Hantana Mountain and its vicinity in Sri Lanka

Abstract

Landslide is one of the common natural disasters experience in central highlands in Sri Lanka. Even though landslide risk predominates in the central highlands, urbanization has been increasing within last three to four decades in this region. This study has focused to classify landslide hazard in the Hantana mountain and its vicinity in the Kandy district which is belong to the central highlands. Initially a base map of the study area was prepared using 1:10,000 topographic sheets of the survey department of Sri Lanka. According to the criteria of landslide hazard and risk classification introduced by the National Building Research Organization (NBRO) - Sri Lanka, bedrock geology, surface deposits, slope, hydrology and drainage, land use and landform are the main six factors influenced to create landslides. Also based on the influence of creating landslide, this criterion has introduced different weightages and ranks for each factor and conditions within each factor respectively. These weightages and ranks are considered to create weighted thematic layers for six factors mentioned in the above using hard copy maps, digital maps, and aerial photographs. Thereafter, the landslide hazard map for the study area has created using ArcGIS software with the help of Multi Criteria Decision Analysis (MCDA) method and overlay analysis technique. Finally, landslide hazard map has created and classified into five landslide hazardous zones i.e. very high, high, moderate, low, and very low and are distributed about 4%, 11%, 31%, 33% and 21% of the total extension of the study area respectively.