lecture overview - · pdf file1 1 lecture overview definition: geomorphology geomorphic...
TRANSCRIPT
1
1
Lecture Overview
Definition: geomorphologyGeomorphic mappingReview: Landslide terminology & classification systemsCharacteristics of landslidesMapping of landslide typesExamples of geomorphic mapping in landslide studies
2
Linkages
Form
Material
Process
Geomorphology is the science of relief forms, forming materials and the changing processes.
Rotmoostal /Gurgler Tal
2
3
Iceland - Photopraphs
Aerial photography of Bíldudalur, viewto North
Bíldudalur,Westfjords
(Photo: Matz Wibelund)
Glade & Jensen 2002
4
Geomorphological map
Glade & Jensen (2004)
Geomorphic mapping
3
5
Sediment origin
Soil creep / solifluction
Appl. Model
Assumption: 25mm/yr with 0.5m
6
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto
& D
ikau
, 200
4
4
7
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Thematic components of the geomorphologic map of the Turtmann valley
Otto
& D
ikau
, 200
4
Field observationHatched polygonsNot specifiedSubsurface Material
Field observation,topographic maps
Line symbols and polygons
Not specifiedHydrology/Glaciology
Field observation,process recognition,material properties, inferring of past processes based on landform geometry and material.
Coloured polygonsAll scales (active and past processes)
Process Domain
Field observation, analysis of DTM and topographic maps
Line symbolsNot specifiedGeomorphography(steps and breaks of slope, valleys and drainage ways)
Field observationLine or point symbolsPartly specifiedSingular Landform
Field observation,state of activity according to indicators (see text)
Point symbols (red or black)
Activity 1 in the last 5 years (red)No Activity in the last 5 years (black)
GeomorphologicProcess
Information sourceMap legend symbolTemporal scaleThematic layers
1Types of activity: continuous, intermittent, episodic, singular
8
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Qualitative sediment flux model of the Brändjitälli hanging valley
Otto
& D
ikau
, 200
4
5
9
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
10
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
6
11
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
12
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
7
13
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
14
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
8
15
Example: Geomorphic mapping in the Turtmannvalley, Switzerland
Otto & Dikau, 2004
16
Example: Sediment storage - Rain valley, Germany
9
17
Linking storage – process / Activity of storages
18
Geomorphic mapping in landslide studies
Mös
sing
en-Ö
schi
ngen
GMK 25Leser 1972
10
19
Landslide terminologyCrownMain scarpTopHeadMinor scarpMain BodyFootTipToe
Surface of ruptureSurface of separationZone of depletion
Zone of accumulationDepletionDepleted massAccumulationFlank
Adopted from Cruden & Varnes, 1996
20
Landslide classifications
Material: Rock, Soil, Lithology, structure, Geotechnical properties
Geomorphic attributes: Weathering, Slope formLandslide geometry: Depth, Length, Height etc.Type of movement: Fall, Slide, Flow etc.Climate: Tropical, Periglacial etc.Water: Dry, wet, saturatedSpeed of movement: Very slow, slow etc.Triggering mechanism: Earthquake, rainfall, etc.
11
21
Landslide classifications (1/3) – Sharpe 1938
Material: earth, rockMovement: flow, slipVelocity: slow to very rapidWater/ice content
22
Landslide classifications (2/3) – Varnes 1978
Material: bedrock, debris, earthMovement: fall, topple, slide, flow, complexSecondary: water content, velocity
12
23
Landslide classifications (3/3) – Wieczorek 1984
YESF:Y = Dormant-YoungE = EarthS = SlideF = Flow
24
Landslide characteristics: Morphology
13
25
Landslide characteristics: Vegetation
26
Landslide characteristics: Drainage
14
27
Landslide characteristics: Active vs. Non-active
28
Mapping Landslide Types
15
29
Mapping Landslide Types
30
Field methods – topographic measurements Tachymeter
Petrahn 1996
Petrahn 1996
Großmann 1983
Keaton & de Graff1996
16
31
Field methods – topographic measurements Tachymeter
Petrhn 1996
Keaton & de Graff 1996
32
Natural Hazards/Risk & Geomorphology
Geomorphologic mappingIdentification of distributions of processesEstimation of temporal occurrenceAnalysis of materialAssessment of sediment storageBasic information for process modeling
Geomorphologic process studiesVerification of assumptionsEstimation of sediment production
17
33 Demoulin & Glade 2004
Mapping
34
GPS
Demoulin & Glade 2004
Period: Okt 01 – Mai 02Okt-Dez: no movementJan: 3cm – snow meltingFeb: ~30cm – heavy rainfallsMarch: no movement
Field methods – topographic measurements
18
35
Geomorphic mapping
Legend of Terhorst (2001)
36
Geomorphic mapping
19
37
Geomorphic mapping
38
General geomorphological Mapping with focus on landslides1:50,000(Kallinich 1999)
Only cuesta and landslide heads were mapped
Geomorphic mapping in landslide studies
20
39
Geomorphic mapping in landslide studiesM
össi
ngen
-Ösc
hing
en
40
Geomorphic mapping in landslide studies
Geological profile derivedfrom geomorphologicalmapping
21
41
Geomorphic mapping in landslide studiesM
össi
ngen
-Ösc
hing
en
42
Geomorphic mapping in landslide studies
Mös
sing
en-Ö
schi
ngen
22
43
Geomorphic mapping in landslide studiesM
össi
ngen
-Ösc
hing
en
44
Elements at risks - Houses
Mös
sing
en-Ö
schi
ngen
23
45
Elements at risk – Classified regionsM
össi
ngen
-Ösc
hing
en
46
Elements at risk – Classified regions
Mös
sing
en-Ö
schi
ngen
24
47
Mapping of Rockfall impact – (1/2)
Wieczoreck et al. (2000)
48
Mapping of Rockfall impact – (2/2)
Wieczoreck et al. (2000)
25
49
ConclusionForm – Geomorphometric features• Approximation of age• Topographic measurements (Tachymeter, GPS)
Material – Near subsurface material• 1m drillings
Process domains• Dominant process – spatially distributed• Grade of activity
50
ReferencesCruden, D.M. and Varnes, D.J. 1996: Landslide types and processes. In Turner, A.K. and Schuster, R.L., editors, Landslides: investigation and mitigation,Washington, D.C.: National Academey Press, 36-75.Demoulin, A. and Glade, T. in prep.: Recent landslide activity in Manaihan, Belgium. Landslides.Glade, T. and Jensen, E.H. 2004: Landslide hazard assessments for Bolungarvíkand Vesturbyggð, NW-Iceland. Reykjavik: Icelandic Meteorological Office.Glade, T., Kadereit, A. and Dikau, R. 2001: Landslides at the Tertiary escarpement of Rheinhessen, Southwest Germany. Zeitschrift fürGeomorphologie, Supplement Band 125, 65-92.Kallinich, J. 1999: Verbreitung, Alter und geomorphologische Ursachen von Massenverlagerungen an der Schwäbischen Alb auf der Grundlage von Detail-und Übersichtskartierungen.Knödel, K., Krummel, H. and Lange, G., editors 1997: Geophysik. Berlin: Springer Verlag.Reynolds, J.M. 1997: An Introduction to Applied and Environmental Geophysics. Chichester, UK: John Wiley & Sons.
26
51
ReferencesSharpe, C.F.S. 1938: Landslides and Related Features - A Study of Mass Movements of Soil and Rock. New York. pp. 137.Selby, M.J. 1993: Hillslope materials and processes. Oxford: Oxford University Press.Otto, J.-C. and Dikau, R. 2004: Geomorphic system analysis of a high mountain valley in the Swiss Alps. Zeitschrift für Geomorphologie N.F. 48, 323-341.Terhorst, B. and Kirschhausen, D. 2001: Legends for mass movements in the MABIS-Project. Zeitschrift für Geomorphologie, Supplement Band 125, 177-192.Varnes, D.J. 1978: Types of slope movement.Wieczorek, G.F. 1984: Preparing a Detailed Landslide-Inventory Map for Hazard Evaluation and Reduction. Bulletin of the Association of Engineering Geologists21, 337-342.Wieczorek, G.F., Snyder, J.B., Waitt, R.B., Morissey, M.M., Uhrhammer, R.A., Harp, E.L., Norris, R.D., Bursik, M.I. and Finewood, L.G. 2000: Unusual July 10, 1996, rock fall at Happy Isles, Yosemite National Park, California. GSA Bulletin no.1, 75-85.