Effects of volume and topographic parameters on rockfall travel distance: a case study from NW Himalayas, Pakistan

This paper presents an analysis of rockfall travel distance for incidents along the roads of the Abbottabad and Mansehra Districts, Khyber Pakhtunkhwa, Pakistan. Data for 121 rockfall events ranging from 100 m 3 to 10 000 m 3 volume were gathered during field investigations and used to facilitate an assessment of parameters such as height of fall, travel angle, travel distance and rockfall volume. The relationship between the height of fall and travel distance was investigated using well-established empirical approaches published in the literature. This analysis showed that travel angle decreased with increase in the rockfall volume, but that there was a weak correlation between the volume of rockfall and travel distance. A strong positive relationship between the travel distance and the height of fall was also identified. Comparison of the rockfall events identified during this study and existing data published from other regions in the world shows that the characteristics of the rockfalls are largely consistent with those identified by previous investigations. The study findings provide a useful set of data for empirical analyses that may be used for hazard and risk assessment in the region.