Suggested nomenclature for landslides - Springer Link

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These have been largely adop- ted by the leading North American geological dictio- nary (Bates and Jackson, 1987). French language terminology follows theĀ ...
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BULLETIN

of the International Association of ENGINEERING

N~

GEOLOGY

de I'Association Internationale de GEOLOGIE DE L'INGI~NIEUR

SUGGESTED NOMENCLATURE

41

PARIS

1990

FOR LANDSLIDES

P R O P O S I T I O N D E D I ~ F I N I T I O N S P O U R LA D E S C R I P T I O N

DES G L I S S E M E N T S

DE TERRAIN

IAEG Commission on Landslides *

Abstract The IAEG Commission on Landslides and other Mass Movements on Slopes has proposed English and French names for 19 identifiable features of slope movements and for 7 dimensions of those features. The Commission intends to publish this list in other languages and to supplement and revise it from time to time.

Rrsume La Commission de r A I G I ~ Glissements de terrain et autres mouvements des sols ~ sugg~re des termes anglais et franqais pour 19 61~ments caractrristiques des mouvements de pentes et pour 7 dimensions de ces 61ements. La Commission publiera cette liste en d'autres langues et aussi t'augmentera et la r~visera de temps en temps.

Introduction

Since its inception in 1968, the IAEG Commission on Landslides and Other Mass Movements on Slopes has been concerned with establishing the nomenclature of slope movements. A basic task of the Commission was to correlate the various national terminologies and classifications of slope movements to enable mutual understanding between the scientists of individual countries (Pasek, 1971). The first meeting of the Commission in 1970 resolved to compile an illustrated terminological glossary. Chairman Pasek sent Commission members a drawing of a typical landslide to be completed with corresponding terms used in their countries. By the end of 1971 responses had been received. However, in 1973, several members had not yet submitted their final drafts and were urged to do so (Pasek, 1973). Meanwhile Pasek synthesized the landslide terminology with the preparatory work of the IAEG Working Group on Terminology for a Dictionary of Engineering Geology. In 1975, Pasek sent a review of English terminology concerning landslides and other mass movements to Commission members from English speaking countries for editing. The revised terminology was then submitted to the IAEG Working Group on Terminology. Much of the Commission's activity on terminology was motivated by its 1971 commitment to supply the landslide information to the UNESCO Annual Summary of

*

Chairman

:

Information on Natural Disasters (UNESCO, 1973, 1974, 1976, 1979). This ceased publication in 1979. Under Chairman Hutchinson, the Commission then focused on the problems of classifying debris flows and a number of papers on this topic will appear in IAEG Bulletins. The imminent International Decade for Natural Disaster Reduction and the proposed World Inventory of Landslides have suggested, however, that the publication of this nomenclature is now timely.

Nomenclature

We have divided landslide nomenclature into two groups, those terms that refer to identifiable features of the slope movement and those terms that refer to the dimensions of those features. The English language terms are based (unless otherwise noted) on those proposed in a review by Commission member Varnes in 1978 (Varnes, 1978). These have been largely adopted by the leading North American geological dictionary (Bates and Jackson, 1987). French language terminology follows the review by Colas and Commission member Pilot (Colas, Pilot, 1976) unless otherwise noted. Numbers placed next to the terms refer to those on Figure 1. We have begun on the crown and proceeded

D.M. Cruden. Department of Civil Engineering, University of Alberta, Edmonton, Alberta, Canada T6G 2G7.

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Plan

Head (4): The upper parts of the landslide along the contact between the displaced material and the main scarp (2).

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Minor scarp (5) : A steep surface on the displaced material of the landslide, produced by differential movements within the sliding mass. Main body (6) : The part of the displaced material of the landslide that overlies the surface of rupture between the main scarp (2) and the toe of the surface of rupture (11). Foot (7): The portion of the landslide that has moved beyond the toe of the surface of rupture (11) and overlies the original ground surface. Tip (8): The point of the toe (9) farthest from the top (3) of the landslide. Toe (9) : The lower, usually curved margin of the displaced material of a landslide, it is the most distant from the main scarp (2).

Sections

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A

15

Surface of rupture (I0) : The projection of the main scarp (2) surface under the displaced material of a landslide. Toe of surface of rupture (11) : The intersection (sometimes buried) between the lower part of the surface of rupture (10) of a landslide and the original ground surface. Surface of separation (12) : The part of the original ground surface overlain by the foot (7) of the landslide.

Fig. 1 : Suggested nomenclature for landslides. Cross hatching indicates undisturbed ground, stippling shows the extent of the displaced material (13).

down the movement to its tip, returning by an underground route, then turned our attention to the flanks. Terms are thus not arranged in alphabetic order (either in English or in French).

Landslide features Crown (1) : The practically undisplaced material still in place and adjacent to the highest parts of the main scarp. Main scarp (2) : A steep surface on the undisturbed ground at the upper edge of the landslide, caused by movement of the slide material away from the undisturbed ground. Top (3) : The highest point of contact between the displaced material (13) and the main scarp (2).

Displaced material (13) : Material displaced from its original position on the slope by movement in the landslide. Zone of depletion (14) : The area of the landslide within which the displaced material (13) lies below the original ground surface. Zone of accumulation (15) : The area of the landslide within which the displaced material lies above the original ground surface. Depletion (16) : The volume bounded by the main scarp (2), the depleted mass (17) and the original ground surface (Cruden, 1980). Depleted mass (17) : Part of the displaced material which overlies the rupture surface (10) but underlies the original ground surface. Accumulation (18) : The volume of the displaced material (13) which lies above the original ground surface (Cruden, 1980).

15 Flank (19): The side of the landslide. Compass directions are preferable in describing the side but if left and right are used, they refer to the slide viewed from the crown.

Caract~ristiques du glissement Couronne (1) : Zone siture au-dessus de l'escarpement principal (2), souvent peu affectre par les drsordres. Seules quelques fissures ou crevasses trmoignent de la mise en traction des terrains dans cette zone. Escarpement principal (2) : Surface inclinre ou verticale souvent concave, limitant le glissement ~ son extrrmit6 sup~rieure. Sommet (3) : Limite amont du glissement, point le plus 61ev6 ofa le matrriau gliss~ (13) se trouve en contact avec l'escarpement principal (2).

Zone d'accumulation (15) : Zone d'un glissement de terrain o~ la masse gliss+e (13) est au-dessus de la surface topographique originale. Niche d'arrachement (16): Volume situ~ au-dessus de l'escarpement principal et la masse affaissre (17) et au-dessous de la surface topographique originale. Masse affaissre (17) : Partie de la masse glissre (13) recouvrant la surface de glissement (11), qui est siture audessous de la surface topographique originale (Cruden, 1980). Accumulation (18) : Partie de la masse glissre (13) qui est siture au-dessus de la surface topographique originale. Flanc (19) : Limite latrrale du glissement prolongeant l'escarpement principal (2). Le flanc droit est /~ droite quand les flancs sont vus de la couronne.

Landslide dimensions

T~te (4) : Partie amont de la masse glissre sur I'escarpement principal (2).

L~ the length of the rupture surface : the distance from the toe of the surface of rupture to the crown.

Escarpement secondaire (5) : Cicatrice semblable h l'escarpement principal (2) mais visible dans la masse glissre.

Ld length of the displaced mass : the distance from the tip to the top.

Corps (6) : Partie du matrriau gliss~ (13) au-dessus de la surface de glissement (10) en amont du pied de la surface de glissement (1 1). Pied (7) : Partie de la masse gliss~e (13) en aval du pied de la surface de glissement (I 1). Extr~mit~ aval (8) : Extrrmit~ aval du matrriau gliss6 (13). Front (9) : Partie la plus aval du matrriau gliss6 (13), en grnrral de forme convexe. Surface de glissement (10) : Prolongation en profondeur de l'escarpement principal (2) au-dessous de la masse glissre (13). Pied de la surface de glissement (1 1) : L'intersection aval de la surface topographique initiale et la surface de glissement (10). Surface de s~paration (12) : Surface srparant la masse gliss~e (13) des terrains en place, partie de la surface topographique initiale. Mat~riau gliss~ (13) : Matrriau qui a gliss~, partie d'un glissement de terrain. Zone d'affaissement (14) : Zone d'un glissement de terrain oO la masse glissre (13) est au-dessous de la surface topographique originale.

L total length : the distance from the tip of the landslide to its crown. Wr width of the rupture surface : the maximum width between the flanks of the landslide, perpendicular to the length, Lr. Wj width of the displaced mass : the maximum breadth of the displaced mass perpendicular to the length, Ld. D r the depth of the rupture surface : the maximum depth of the rupture surface below the original ground surface measured perpendicular to the original ground surface. D 0 depth of the displaced mass : the maximum depth of the displaced mass, measured perpendicular to the surface of the displaced material.

Dimensions du glissement Lf longueur de la surface de rupture : distance entre le front de la surface de rupture et la couronne. L~ Iongueur de la masse glissre : distance entre le sommet et l'extrrmit~ aval. L longueur totale : distance entre la couronne et le front de la masse glissre. W r largeur de la surface de glissement : distance maximum entre les flancs.

16 W d largeur de la masse glissee : largeur m a x i m u m de la masse gliss6e darts une direction p e r p e n d i c u l a i r e ~ la longueur, Ld. Dr p r o f o n d e u r de la surface de rupture ' distance entre la surface de rupture et la surface t o p o g r a p h i q u e originale. D~ p r o f o n d e u r de la masse glissee : p r o f o n d e u r de la masse gliss6e dans u n e direction p e r p e n d i c u l a i r e ~ la longueur, Ld.

Discussion While the n o m e n c l a t u r e is p u b l i s h e d in the t w o official languages of I A E G a n d the C o m m i s s i o n , the Commission would also welcome n o m e n c l a t u r e in other languages from n a t i o n a l groups or i n d i v i d u a l members. After review, these lists might form a multilinguaI landslide dictionary. The C o m m i s s i o n is also willing to consider a d d i n g to its n o m e n c l a t u r e . Proposed a d d i t i o n s may be sent to the C h a i r m a n of the C o m m i s s i o n . They s h o u l d be a c c o m p a n i e d by d o c u m e n t a t i o n to show that the terms are both in use a n d are useful.

Acknowledgements N o m e n c l a t u r e has c o n c e r n e d the I A E G C o m m i s s i o n since its creation in 1968 a n d all its past a n d current

members have c o n t r i b u t e d to this synthesis, the current m e m b e r s h i p is A p p e n d i x A. J. de Lugt drafted the figure. The m a n u s c r i p t was r e v i e w e d in detail by R. Gervais, R. Schuster a n d D. Varnes.

References BATES R.L., JACKSON J.A., 1987 : Glossary of Geology, American Geological Institute, Falls Church, Virginia, 788 p. COLAS G., PILOT G., 1976: Description et classification des glis,sements de terrain, Bulletin de liaison des laboratoires des ponts et chauss~es, Num6ro sp~ciat, 2, pp. 21-30. CRUDEN D.M., 1980: The anatomy of landslides, Canadian Geotechnical Journal, 17 : 295-300. PASEK J., 1971 : Report on the activity of the Working Group IAEG, Landslides and Other Mass Movements, Bulletin, International Association of Engineering Geology 3 : 69-71. PASEK J., 1973 : Landslides and Other Mass Movements, Bulletin, International Association of Engineering Geology, 8 : 64--66. UNESCO, 1973 : Annual summary of information on natural disasters, 1971. The Unesco Press, Paris, 6 : 65-71. UNESCO, 1974 : Annual summary of information on natural disasters, 1972. The Unesco Press, Paris, 7 : 68-75. UNESCO, 1976 : Annual summary of information on natural disasters, 1974. The Unesco Press, Paris, 9 : 73-80. UNESCO, 1979 : Annual summary of information on natural disasters, 1975. The Unesco Press, Paris, 10 : 85-88. VARNES D.J., 1978: Slope Movement Types and Processes, in Schuster R.L., Krizek R.J., eds., Landslides: Analysis and Control, Transportation Research Board, National Academy of Sciences, Washington, D.C., Special Report 176, Chapter 2, 11-33.

Appendix A International Association of Engineering Geology Commission on Landslides and other Mass Movements on Slopes Dr. D.M. Cruden, Chairman Dept. of Civil Engineering University of Alberta Edmonton, Alberta T6G 2G7 CANADA

Dr. R.K. Bhandari Director Central Building Research Institute Roorkee, UP, PIN 247672, INDIA

Ing. S. Novosad GEOtest np Gottwaldova 287 709 00 Ostrava, CZECHOSLOVAKIA

Professor V. Cotecchia Direttore, lnstit. Geologia Applicata and Geotecnica University of Bari Via Re David 200 1-70125 Bari, ITALY

Dr. G.A.F. Pilot Laboratoire Central des Ponts et Chauss6es 58 boulevard Lefebvre 75732 Paris, Cedex 15, FRANCE Dr. E. Krauter Geologisches Landesamt Rheinland-Pfalz Flachsmarkstrasse 9 6500 Mainz, GERMANY

Dr. H. Nakamura Public Works Research Institute Ministry of Construction Government of Japan 1, Ashahi, Tsukuba-shi Ibaraki-ken, 305 JAPAN Dr. C.O. Okagbue Department of Geology Faculty of Physical Sciences

University of Nigeria Nsukka Campus NIGI~RIA Professor Zhang Zhuoyuan President Chengdu College of Geology Chengdu, Sichuan, 610059 PEOPLE'S REPUBLIC OF CHINA Professor J.N. Hutchinson Department of Civil Engineering Imperial College London, SW7 2BU UNITED KINGDOM Dr. D.J. Varnes United States Geological Survey MS 903, Box 25046 Denver, Colorado U.S.A., 80225 Professor Dr. G.I. Ter-Stepanjan 9, avenue Lenin, apartment 11 Yerevan 375002 U.S.S.R.