Geophysical investigations on the contribution of irrigation channels to landslide activity in Tusion, Tajikistan
Keywords:
post-glacial landslide, gravitational creep, refraction seismics, geoelectrics, water infiltration, irrigation channelsAbstract
Post-glacial geomorphological settings bearing vast amounts of colluvium as well as alluvial and moraine deposits are typical features in high mountainous environments such as the Himalayas, the Hindu Kush, the Pamir, the Karakoram and the Tien Shan. Due to a lack of alternative living space in narrow valleys, agglomerations are often located on these unstable grounds and regularly experience displacements across the ground surface and subsequent damage to building stock and infrastructure.
Hosting two post-glacial landslide deposits and one gravitational creep within its inhabited areas, the village of Tusion, South-Western Tajikistan, was chosen to conduct geophysical surveys with the aim to determine the geomorphological causes of regularly experienced slope deformations with a particular interest in the contribution of non-isolated irrigation channels crossing the mountain flanks. Over the last two decades, uncontrolled seepage from a network of small-scale irrigation channels is believed to be responsible for water infiltration to deeper horizons and–thereby–reactivate ancient sliding surfaces within the two landslide deposit zones. Also, the gravitational creep in one village part seems to be likewise triggered.
Using refraction seismics and Schlumberger geoelectrics, stratigraphic structures, properties of involved rock material and saturation patterns were assessed in order to provide complementary information about the underground of concerned slopes to a previously conducted hazard assessment by separate Non-Governmental Organizations. Results of the geophysical surveys show conclusive correlations with the hazard maps and local damage reports straining that one of the major destabilizing factors for all concerned slopes consists of uncontrolled water dissipation to the underground.
References
Bichler, A., Bobrowsky, P., Best, M., Douma, M., Hunter, J., Calvert, T., Burns, R., 2004. Three-dimensional mapping of a landslide using a multi- geophysical approach: the Quesnel Forks landslide. Landslides, 1(1), 29-40.
Bogoslovsky, V. A., Ogilvy, A. A., 1977. Geophysical methods for the investigation of landslides. Geophysics, 42(3), 562-571.
Breckle, S. W., Kleinn, E., 2011. Vegetation. In: Hauser, M. The Pamirs. Tourist Map of Gorno-Badakhshan. Gecko Maps, Zurich.
Brooke, J. P., 1973. Geophysical investigation of a landslide near San Jose, California. Geoexploration, 11(2), 61-73.
Brookfield, M. E., 2000. Geological development and Phanerozoic crustal accretion in the western segment of the southern Tien Shan (Kyrgyzstan, Uzbekistan and Tajikistan). Tectonophysics, 328(1), pp. 1-14.
Cummings, D., Clark, B. R., 1988. Use of seismic refraction and electrical resistivity surveys in landslide investigations. Bulletin of the Association of Engineering Geologists, 15(4), 459-464.
FOCUS (Focus Humanitarian Assistance), NFG (Norwegian Forestry Group), NGI (Norwegian Geotechnical Institute), MSDSP (Mountain Society Development Support Program), 2009.
Final report on the hazard and vulnerability risk assessments conducted in the Tusyon Sub-district of the Roshtqala District in the Gorno-Badakhshan Autonomous Oblast of Tajikistan. FOCUS Humanitarian Assistance, Khorog, 19 p.
Glade, T., Stark, P., Dikau, R., 2005. Determination of potential landslide shear plane depth using seismic refraction - a case study in Rheinhessen, Germany. Bulletin of Engineering Geology and Environment, 64(2), 151-158.
Google Earth, 2012. CNES/Spot Image. Hack, J. T., 1957. Studies of longitudinal stream profiles in Virginia and Maryland. United States Geological Survey Professional Paper, 294B, 59 p.
Hack, R., 2000. Geophysics for slope stability. Surveys in Geophysics, 21(4), 423-448.
Havenith, H. B., Jongmans, D., Abdrakhmatov, K., Trefois, P., Delvaux, D., Torgoev, I.A., 2000. Geophysical investigations of seismically induced surface effects: case study of a landslide in the Suusamyr Valley, Kyrgyzstan. Surveys in Geophysics, 21(4), 349-369.
Havenith, H. B., Torgoev, I., Ischuk, A., 2018. Integrated Geophysical- Geological 3D Model of the Right-Bank Slope Downstream from the Rogun Dam Construction Site, Tajikistan. International Journal of Geophysics, 2018(ID 1641789), 16 p.
INTERPEX, 2008a. IXRefraX Instruction Manual (version 1.2). Interpex Limited, Golden, 73 p.
INTERPEX, 2008b. IX1D Instruction Manual (version 1.0). Interpex Limited, Golden, 67 p.
Jongmans, D., Garambois, S., 2007. Geophysical investigation of landslides: a review. Bulletin Société Géologique de France, 178(2), 101-112.
Karapetov, S. S., Sonin, I. I., Khain, V. Y., 1975. On some important features of structure and evolution of the Afghan-Pamir segment of the Alpine fold belt. Bulletin of the Moscow University of Geology, 3, 38-46. (in Russian)
Konagai, K., Numada, M., Zafeirakos, A., Johansson, J., Sadr, A., Katagiri, T., 2005. An example of landslide-inflicted damage to tunnel in the 2004 Mid- Niigata prefecture earthquake. Landslide, 2(2), 159-163.
Kordonskaya, N. W., Shebalin, N. W., 1977. New strong earthquake catalog for the territory of the USSR from the past to the year 1975. Nauka, Moscow, 536 p. (in Russian)
Kreutzmann, H., 2011a. Pamir ecology: glaciers and high mountain desert. In: Hauser, M. The Pamirs. Tourist Map of Gorno-Badakhshan. Gecko Maps, Zurich.
Kreutzmann, H., 2011b. Introduction. In: Hauser, M. The Pamirs. Tourist Map of Gorno-Badakhshan. Gecko Maps, Zurich.
Mauritsch, H. J., Seiberl, W., Arndt., R., Römer, A., Schneiderbauer, K., Sendlhofer, G. P., 2000. Geophysical investigations of large landslides in the Carnic Region of southern Austria. Engineering Geology, 56(3-4), 373-388.
Searle, M., 2008. Geology of Tajikistan. In: Middelton, R., Thomas, H. Tajikistan and the High Pamirs. Odyssey Books & Guides, Hong Kong, 236-240.
Singh, R. P., Dubey, C. S., Singh, S. K., Shukla, D. P., Mishra, B. K., Tajbakhsh, M., Ningthoujam, P. S., Sarma, M., Singh N., 2012. A new slope mass rating in mountainous terrain, Jammu and Kashmir Himalayas: application of geophysical technique in slope stability studies. Landslides, 10(3), 255-265.
Slavin, V. I., 1976. Tectonics of Afghanistan. Nedra, Moscow, 204 p. (in Russian)
Strom, A., Abdrakhmatov, K., 2018. Rockslides and Rock Avalanches of Central Asia - Distribution, Morphology, and Internal Structure. Elsevier, Oxford, 458 p.
