The Importance Of Landslides In Ethiopia

1.1 Introduction

1.1.1 Background

Landslides belong to the most destructive phenomena of nature that cause damage to both property and life every year throughout the world. For example, a report from the year 2001 in the United States, landslides caused approximately 3.5 billion dollars in damage, and kill between 25 and 50 people annually (US Geological Survey Fact Sheet 2004). Therefore, the study of landslides has drawn global attention mainly due to increasing awareness of its socio-economic impacts and also increasing pressure of urbanization on the mountain environment (Aleotti and Chowdhury, 1999; Kanungo et al., 2006).

In Ethiopia, landslide hazard is one of the crucial environmental problems for all the activities performed

Several field-based hazard zonation techniques have been applied in the last few decades to the problem of landslide categorization in Ethiopia. These include: heuristic approach or expert evaluation techniques; the landslide hazard zonation evaluation factors (LHEF) (Anbalagan, 1992); slope susceptibility evaluation parameter (SSEP) rating approach (Raghuvanshi et al., 2014); and statistical analysis approaches.

Most of the people of the countryside in the present study area are living near to the toe and sloppy side of mountain leaving the plain land for agricultural purpose. In towns also, due to the shortage of suitable lands for building construction, as a result of increasing number of population, and increased cost of land, peoples are forced to live in mountainous area. Therefore, the population in the area is vulnerable to the risks of landslides. Therefore, it is of utmost importance to delineate the area into various hazard zones so that appropriate mitigation measures may be worked out or the high hazard zones may be avoided for any developmental works in the

However, effective landslide mitigation requires new methodologies to develop a better understanding of landslide hazard and to make rational decisions on the allocation of funds for management of landslide risk (Dai et al., 2002). In this context, a new slope susceptibility evaluation parameter (SSEP) rating scheme was developed by Raghuvanshi et al., (2014) as an approach for landslide hazard zonation by considering both intrinsic and external triggering parameters that are responsible for slope instability. The SSEP technique was successfully applied in the area around Wurgessa Kebelle of North Wollo Zone, Amhara National Regional State, which is also situated about 150 km northeast of the present study area. The results pointed out that all past landslide activities and potential instability areas were found to be within very high- and high hazard zone of the landslide hazard zonation map prepared during the study. Thus, according to Raghuvanshi et al. (2014), this satisfactory agreement confirmed the rationality of considered governing parameters, the adopted SSEP technique, tools and procedures in developing the landslide hazard map of the study