Rockfall hazard and risk assessment: an example from a high promontory at the historical site of Monemvasia, Greece

H Saroglou,V Marinos,P Marinos,G Tsiambaos

doi:10.5194/nhess-12-1823-2012

Abstract

Abstract. The paper presents the kinematics of rock instability of a high limestone promontory, where the Monemvasia historical site is situated, in Peloponnese in Southern Greece. The instability phenomena poses a significant threat to the town located at the base of the slope. Rockfall episodes occurred in the past due to the relaxation of the high cliff, whereas significant undermining of the castle frontiers has been observed at the slope crest. The predominant types of instability are of planar, wedge and toppling failure of medium to large blocks. In order to investigate the existing stability conditions and decide upon the protection measures, stability and rockfall analyses were carried out for numerous slope sections under different loading conditions and protection measures were suggested. A rock-fall risk rating system is proposed, which is based on morphological and structural criteria of the rock mass and on vulnerability and consequences. The rating system is applied for individual sections along the slope and a risk map was produced, which depicted areas having different degree of risk against rockfall occurrences.

Highlights

The impact of rockfalls on archaeological sites and historical monuments in the Greek territory is significant, since most of the landscapes are mountainous and the sites are usually found near or on steep rock slopes
The main scope of the paper is the presentation of a new rock-fall risk rating system, which is based on morphological and structural criteria of the rock mass and on vulnerability and consequences
This system is applied for the risk assessment of the rock slopes on the Monemvasia historical site

Summary

Introduction

The impact of rockfalls on archaeological sites and historical monuments in the Greek territory is significant, since most of the landscapes are mountainous and the sites are usually found near or on steep rock slopes. The main scope of the paper is the presentation of a new rock-fall risk rating system, which is based on morphological and structural criteria of the rock mass and on vulnerability and consequences. This system is applied for the risk assessment of the rock slopes on the Monemvasia historical site. The site is a typical example with high impact of rockfalls. The city at the foot is inhabited and attracts many visitors under a high risk

Methods

Results

Conclusion