A study on landslides and subsurface piping, facilitated by dykes, using vertical electrical sounding and δO18 and δH2 stable isotopes

• Published in: Bulletin of engineering geology and the environment 2017-11, Vol.76 (4), p.1297-1306
• Main Authors: Sajinkumar, K. S., Unnikrishnan Warrier, C., Muraleedharan, C., Shahul Hameed, A., Rani, V. R., Pradeepkumar, A. P., Sundarajan, P.
• Format: Article
• Language: English
• Subjects: Dikes; Earth and Environmental Science; Earth Sciences; Electrical raceways; Electrical resistivity; Foundations; Geochemistry; Geoecology/Natural Processes; Geoengineering; Geological engineering; Geotechnical Engineering & Applied Earth Sciences; Hydraulics; Isotopes; Landslides; Nature Conservation; Original Article; Piping; Sequencing; Soundings; Stable isotopes
• ISSN: 1435-9529; 1435-9537
• DOI: 10.1007/s10064-017-1056-x

A combination of vertical electrical sounding (VES) and δO 18 and δH 2 stable isotope geochemistry is used in this study to trace out the extension of a dyke and for deciphering the subsurface piping phenomena in a landslide-affected hamlet, Pasukadavu, in the Western Ghats of Kerala, India. VES was successful in extracting three to four different subsurface layers characterized by differing resistivity. Two VES sections were prepared from 24 different VES locations, each one for understanding the dyke extension and for delineating subsurface conduits. The dyke was characterized by high resistivity of 800–5000 Ω.m and shows varying thickness. In the second profile, the void zone, which is characteristic of piping, is delineated through a low resistivity zone (75 to 350 Ω.m). δO 18 and δH 2 stable isotopes collected along the second VES profile show the same chemistry, indicating that it is the same water which flows all along the VES profile 2. A four-stage conceptual model was developed to illustrate and narrate the sequence of development of the piping phenomena and landslide activity.