Assessment of Rockfall Hazard on Steep Slopes: Ermenek (Karaman, Turkey)

Ermenek is a extraordinary settlement area due to its topographical features in Karaman (Turkey). The city is located in the northern side of the steep cliffs, which are formed of jointed limestone that abruptly increases from 1250 m to 1850 m. Moreover, these cliffs, having a slope dip of nearly 90°, are the main rockfall source areas due to their lithological characteristics, climatic effects and the engineering properties of rock units. Up to now, depending on the rockfall event, nearly 500 residences have been severely damaged, and the loss of life has occurred in Ermenek. The rockfall phenomenon is initiated by discontinuities, lithological changes, weathering and the freeze-thaw process in the study area. In this study, extensive fieldwork including the determination of locations and dimensions of hanging, detached and fallen blocks; a detailed discontinuity survey; and the description of geological, morphological and topographical characteristics was performed. Additionally, rockfall hazard has been evaluated by two-dimensional rockfall analysis involving 10 profiles. While these profiles were determined, the locations where the most of the fallen blocks are observed are selected in the field study. During the rockfall analysis, run-out distance, bounce height, kinetic energy and the velocities of various sizes of blocks for each profile were determined through the use of RocFall v4.0 software. The results obtained from the rockfall analysis were used to map the areas of possible rockfall hazard zones, and rockfall source areas were interpreted. According to the rockfall analysis, field study and laboratory testing, protective and preventive recommendations can be suggested for the areas threatened by rockfall. However, the most widely known remedial measures in literature, such as trenches, retaining walls (barriers), wire mesh, cable/stretching nets and rock bolting, etc., are not sufficient in the study area due to its topographical, atmospheric and lithological features. For these reasons, hanging blocks in the reachable locations can be removed, the total evacuation of the danger zone may applied, and then taking safety measures in this area to make it safer for the residents.

Anahtar Kelimeler:

Ermenek, hazard, limestone, rockfall, zonation map

PDF

___

Agliardi F, Crosta GB., 2003. High resolution three-dimensional numerical modelling of rockfalls. International Journal of Rock Mechanics and Mining Science, 40, 455–471. Azzoni A, de Freitas MH.,1995. Experimentally gained parameters, decisive for rockfall analysis. Rock Mechanics and Rock Engineering 28(2), 111–124.
Bassant, P., van Buchem, F.S.P., Strasser, A. and Görür N., 2005. The stratigraphic architecture and evolution of the Burdigalian carbonate–siliciclastic sedimentary systems of the Mut basin, Turkey. Sedimentary Geology, 173, 187-232.
Bassato G, Cocco S, Silvano S., 1985. Programma di simulazione per lo scoscendimento di blocchi rocciosi. Dendronatura, 6(2), 34–36.
Binal A, Ercanoğlu M., 2010. Assessment of rockfall potential in the Kula (Manisa, Turkey) Geopark Region. Environmental Earth Science, 61, 1361–1373.
Bozzolo D, Pamini R., 1986. Modello matematico per lostudio della caduta dei massi. Laboratorio di FisicaTerrestre ICTS. Dipartimento Pubblica Educazione, Lugano-Trevano. Bourrier, F., Berger, F., Tardif, P., Dorren, L. and Hungr, O., 2012. Rockfall rebound: comparison of detailed field experiments and alternative modelling approaches. Earth Surface Process. Landforms.
Buzzi O, Giacomini A, Spadari M., 2012. Laboratory investigation on high values of restitution coefficient Rock Mechanics and Rock Engineering 45, 35-43.
Chau KT, Wond RHC, Lee CF.,1996. Rockfall problems in Hong Kong and some new experimental results for coefficient of restitution. International Journal of Rock Mechanics and Mining Science, 35, 662–663.
Chen H, Chen RH, Huang T.,1994. An application of an analytical model to a slope subject to rockfalls Bulletin of Engineering Geology and Environment, 31, 447–458.
Dorren LKA., 2003. A review of rockfall mechanics and modeling approaches. Progress in Physical Geography, 27(1), 69–87.
Dorren LKA, Maier B, Putters US, Seijmonsbergen AC., 2004. Combining field and modelling techniques to assess rockfall dynamics on a protection forest hillslope in the European Alps Geomorphology, 57, 151–167.
Duncan C. Wyllie, 2014. Calibration of rock fall modeling parameters, International Journal of Rock Mechanics and Mining Sciences, 67, 170-180.
Evans SG, Hungr O.,1993. The assessment of rockfall hazard at the base of talus slopes. Canadian Geotechnical Journal, 30, 620–636.
Falcetta JL.,1985. Un nouveau mod’’ele de calcul de trajectoires de blocs rocheux. Revue Francaise de Geotechnique, 30, 1–17.
Guzzetti F, Crosta G, Detti R, Agliardi F., 2002. STONE: a computer program for the three-dimensional simulation of rockfalls. Computer Geoscience, 28, 1079–1093.
Guzzetti F, Reichenbach P, Wieczorek GF., 2003. Rockfall hazard and risk assessment in the Yosemite Valley, California, USA. Natural Hazards and Earth System Science, 3, 491–503.
Gul M and Eren M., 2003. The sedimentary characteristics of Dagpazarı patch reef (Middle Miocene, Mut-Icel/Turkey). Carbonates and Evaporites, 18 (1), 51-62
Hoek E.,1987. Rockfall—a program in BASIC for the analysis of rockfall from slopes. Unpublished note, Golder Associates/ University of Toronto, Canada. Hoek E., 2007. Practical rock engineering. Course note.
Ilgar, A. and Nemec, W., 2005. Early Miocene lacustrine deposits and sequence stratigraphy of the Ermenek Basin, Central Taurides, Turkey. Sedimentary Geology, 173, 233–275.
Jones CL, Higgins JD, Andrew RD., 2000. Colorado rockfall simulation program version 4.0. Colorado Department of Transportation, Colorado Geological Survey.
Katz O, Reichenbach P, Guzzetti F., 2011. Rock fall hazard along the railway corridor to Jerusalem, Israel in the Soreq and Refaim valleys. Natural Hazards, 56, 649–665.
Keskin I., 2013. Evaluation of rock falls in an urban area: the case of Boğazici (Erzincan/Turkey). Environmental Earth Science, 70, 1619– 1628.
Okura Y, Kitahara H, Sammori T, Kawanami A., 2000. The effects of rockfall volume on runout distance. Engineering Geology, 58,109–124.
Özgül, N., 1976.Torosların bazı temel jeoloji özellikleri. Türkiye Jeoloji Kururultayı Bülteni, Ankara, 19, 65-78.
Perret S, Dolf F, Kienholz H., 2004. Rockfalls into forest: analysis and simulation of rockfall trajectories-consideration with respect to mountainous forest in switzerland. Landslides, 1,123–130.
Pfeiffer TJ, Bowen TD., 1989. Computer simulation of rockfalls.Bulletin of the International Association of Engineering Geology, 1, 135– 146.
Robotham ME, Wang H, Walton G., 1995. Assessment of risk from rockfall from active and abandoned quarry slopes. Transactions of the Institution of Mining and Metallurgy, 104(1–4), A25–A33.
Rocscience 2002. RocFall software—for risk analysis of falling rocks on steep slopes. Rocscience user’s guide, p 59.
Schweigl J, Ferretti C, Nossing L., 2003. Geotechnical characterization and rockfall simulation of slope: a practical case study from South Tyrol (Italy). Engineering Geology, 67, 281– 296.
Şafak, Ü., 1997. Karaman yöresi Üst Miyosen-Pliyosen istifinin ostrakoda faunası ve ortamsal yorumu. MTA Dergisi, 119, 89-102. Taga, H., Zorlu, K., 2007. Ermenek İlçesindeki (Karaman) Kaya Düşmelerinin Kinetik Enerji Dağılımı Açısından Değerlendirilmesi. 60. Türkiye Jeoloji Kurultayı Bildiri Özleri Kitabı, s.317.
Topal T, Akin M, Ozden AU., 2007. Assessment of rock fall hazard around Afyon Castle, Turkey. Environmental Geololgy, 53, 177–189.
Topal T, Akin M. K., Akin M., 2012. Rockfall hazard analysis for an historical Castle in Kastamonu (Turkey), Natural Hazards 62, 255-274.
Tunusluog˘lu MC, Zorlu K., 2009. Rockfall hazard assessment in a cultural and natural heritage (Ortahisar Castle, Cappadocia, Turkey). Environmental Geology, 56(5), 963–972.
Ulusay R, Gokceoglu C, Topal T, Sonmez H, Tuncay E, Erguler ZA, Kasmer O., 2006. Assessment of environmentel and engineering geological problems for the possible re-use of an abandoned rock-hewn settlement in Ürgüp (Cappadocia) Turkey. Environmental Geololgy, 50, 473–494.
Varnes DJ., 1978. Slopemovement types and processes. In: Schuster RL, Krizek RJ (ed) Landslides, analysis and control. Transportation and Road Research Board, National Academy of Science, Washington, DC, pp 11–33.
Whalley WB., 1984. Rockfalls. In: Brunsden D, Prior DB (eds) Slope stability. Wiley, New York, pp 217–256.
Yılmaz I, Yildirim M, Keskin I., 2008. A method for mapping the spatial distribution of RockFall computer program analyses results using ArcGIS software. Bulletin of Engineering Geology and Environment, 67, 547–554.
Yurtsever, T.Ş., Ilgar, A. ve Gürçay, B., 2005. Ermenek (Karaman)-Mut-Gülnar (İçel) Arasında Kalan Tersiyer Havzasının Jeolojik Ve Sedimantolojik İncelenmesi. MTA Rapor No:10776 (Unpublised).
Zorlu, K., Taga, H., 2009. Effects of geologic factors on rockfall events: Ermenek (Karaman), Turkey. EGU General Assembly 2008, Wien,Austria, Abstract No. EGU2009- A-2882.
Zorlu K, Tunusluoglu MC, Gorum T, Nefeslioglu HA, Yalcin A, Turer D, Gokceoglu C., 2011.
Landform effect on rockfall and hazard mapping in Cappadocia (Turkey). Environmental Earth Science, 62(8), 1685–1693.