1. A Deep-seatedGravitationalSlopeDeformation in the northernMonasheeComplex, Monashee Mountains, British Columbia, Canada Danilo Moretti Earth Science Department Universityof Bologna VisitingStudent

2. Presentation Outline Introduction: What is a deep-seated gravitational slope deformation? Methods of studying DsGSD Different approaches to and representations of DsGSD Objectives for this study Field site description Methodology Timeline

4. Twomainrepresentations Sackung Lateral Spreading open fractures scarps toe bulging of brittle formations on ductile units homogeneous rocks Bisci et al. (1996) Varnes (1978)

6. High variable ratio run-out/volume

8. A slidingsurfaceisnotanessentialfeature (the deformational mechanismiscomplex) “Deep-seatedGravitationalSlopeDeformation”

9. Traditionalapproachesto the studyofDsGSD The geomorphological method: Double ridges Trenches Elongated depressions Sliding steps Isolated rock walls Up hill facing scarps Slope bulgings Talus sheets The structural method: Shear zones Fault scarps Collapse zones Horst and Graben Gravitational Thrusts

12. regional variables, offering a “static” conditioning to the system (e.g. lithology as an “internal” cause of DsGSD controlling shear strenght) Mathews and Monger, 2005 © Google 2009

15. Field mapping

16. GIS

18. Site Description © Google 2009

20. No previous works on DSGsD in this area

22. The Geology of Blais Creek 5 km J. Murray Journeay, 1986

25. “Heritage” of the Evolution of the continental crust in the Monashee Complex R. L. Brown and J. M. Journeay, 1987

28. Linear features in the Blais Creek Area “Passive” origin: Old tectonic linear features “Active” Origin: Release of energy after deglaciation or neotectonic or both

29. L Cross Sections J. Murray Journeay, 1986 E’ E K Legend Da = marble Db = quartize Geological Survey Of Canada, 1964

30. Methods summary Field methods: Mapping of surface features Geotechnical investigation Trench ? Laboratory techniques Yield strength of samples collected in the field Remote sensing and software-aided data analysis Photogrammetry GIS database Geotechnical analysis for numerical modeling

31. Field methods 1: Surface features Map geomorphological features: Double ridges Trenches Elongated depressions Sliding steps Isolated rock walls Antislope scarps Slope bulging Talus sheets Flow of water into and out of slope Glacial features and interaction with DsGSD features Data entered into handheld GPS unit SRG2 toolbar for ArcPad (modified for this project)

32. SRG2 toolbar

33. Field methods 2: Geotechnical Detailed geotechnical characterization of the rock mass: Intact rock strength (Schmidt hammer) Rock mass quality (GSI) Weathering grade and Discontinuities (ISRM) Spot measurements, scanlines in select locations Stereo-couple photographs for later photogrammetry www.abbeyspares.co.uk

37. DsGSD database In concert with Gabriel Hensold Format based on Giardino et al. (2004) First phase: Inventory of data from past published studies in B.C. Naming and localization of sites Geospatial and geotechnical data Interpretations Second phase: add the main data from the European (especially Italian) past published studies Third phase: application of database format to detailed new studies Blais Creek (me) Handcar Peak (Gabriel Hensold)

38. Outline of data entry format General inventory metadata (ID, data source, date, reporter) Geographical position of feature Geomorphology of DsGSD DsGSD geometry Slope morphology Surface deformation features Other landforms Hydrology Structural geomorphology of Valley slopes Slope and bedding/schistosity relationship Orientations of structural discontinuities (foliation, joints, faults) Geology Structural units Lithological units Geotechnical properties Intact rock Rock mass Discontinuities

40. Possible RocPlane prelim analysis

41. Possible Phase2 analysis

42. Explicit model (FLAC or UDEC)Continuum or discontinuum? Depends on stress conditions and the rock mass. Agliardi et al. (2001)

43. Timeline: Summer 2009 Course: Photogrammetry short course with MatthieuSturzenegger Office work: Complete inventory of previous DsGSD studies in B.C. Obtain GIS shape files and Digital Elevation Models from Turin Map surface features at Blais Creek through GIS and Google Earth using digitized aerial photos Plan logistics for field work in Blais Creek and Handcar Peak Field work: Field research at Blais Creek (3-4 weeks) Field research in Handcar Peak (3-4 weeks)

45. Compilation, organization and analysis of spatial and geotechnical data gathered in the field in a GIS database

46. Point load strength testing on rock samples from Blais Creek

47. Creation of initial numerical models

48. Departure for Italy (around 20th of September 2009)

49. Course:

50. Final course – Matlab Class at the University of Bologna

51. Office work:

52. Creation of initial numerical models

54. References Agliardi F, Crosta G, Zanchi A. 2001. Structural constraints on deep-seated slope deformation kinematics. Engineering Geology 59(1-2):83-102. Bovis MJ. 1982. Uphill-facing (antislope) scarps in the Coast Mountains, Southwest British Columbia. Geological Society of America Bulletin 93(8):804-812. Bovis MJ, Evans SG. 1996. Extensive deformations of rock slopes in the southern Coast Mountains, southwest British Columbia, Canada. Engineering Geology 44(1-4):163-182. Giardino M, Giordan D, Ambrogio S. 2004. G.I.S. technologies for data collection, management and visualization of large slope instabilities: Two applications in the Western Italian Alps. Natural Hazards and Earth System Science4(2):197-211. Holm K, Bovis M, Jakob M. 2004. The landslide response of alpine basins to post-Little Ice Age glacial thinning and retreat in southwestern British Columbia. Geomorphology 57(3-4):201-216. Jahn A. 1964 Slopes morphological features resulting from gravitation. Annals of Geomorphology 1964:59. Kinakin D. 2004. Occurrence and Genesis of Alpine Linears Due to Gravitational Deformation in South Western, British Columbia. MSc thesis, Simon Fraser University, Burnaby, BC. Monger JWH, Journeay JM. 1994. Geology of the Southern Coast and Intermontane Belt. Geological Survey of Canada, Open File 2490, map, scale 1:500,000 Nichol SL, Hungr O, Evans SG. 2002. Large-scale brittle and ductile toppling of rock slopes. Canadian Geotechnical Journal 39:773-788. Savage WZ, Varnes, DJ. 1987. Mechanics of gravitational spreading of steep-sided ridges. Bulletin of the International Association of Engineering Geology 35(1):31-36. Stepanek M. 1992. Gravitational deformations of mountain ridges in the Rocky Mountain foothills. Proceedings of the International Symposium on Landslides 6:231-236.

55. Thankyou! John Clague Doug Stead Marco Giardino Dan Gibson And toeveryone in the EarthSciencesDepartmentofSFU….