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Maps are a useful and convenient tool for presenting information on landslideHazards. They can present many kinds and combinations of information at di erentLevels of detail

Three Important Criteria for Landslide Maps

(1) landslide inventory maps( ) landslide susceptibility maps(!) landslide hazard maps

Landslide-inventory maps

" landslide inventory map sho#s the location$ spatial e%tent andtype of landslides in a region $ and records the date of occurrence

and the types of mass movements that have left recognizabletraces in an area #hich can be identi&ed in the &eld$ or in aerialphotographs and satellite Landslide.

Inventory maps are prepared for multiple purposesincluding:

1. 'ocumenting the e%tent of landslide phenomena in areas

. "s a prior step to#ard landslide susceptibility$ hazard$ andrisk assessment.

!. To investigate the distribution$ types$ and patterns oflandslides in relation to geological characteristics.

. To study the evolution of landscapes dominated by mass#asting processes.

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Methods to Generate Landslides inventory maps:

• Image interpretation data collected in this method #ecollect data from aerial photographs$ high resolution satelliteimages$ or hill shading images derived from detailed 'igital*levation +odels.

• Field investigation by mapping landslide signs$ scarp area$accumulation areas$ and veri&cation of landslides mappedthrough image interpretation and,or classi&cation.

• Community reporting $ by intervie#ing local people on

locations$ dates and impacts of past landslide event.

• Archive studies $ by studying ne#spaper archives$ oldreports$ road maintenance reports.

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(1) relict landslides$ ( ) very old landslides$ (!) landslides olderthan 1- 1$ ( ) active landslides in 1- 1$ ( ) active landslides in1- $ (/) landslides in the period 1- 01- /$ ( ) active landslidesin 1- $ (2) landslides in the period 1- 201-2 $ (-) active

landslides in 1-2 $ (13)$ landslides mapped in the &eld in #inter313.

landslide susceptibility map:

landslide susceptibility map goes beyond an inventory map it’s detect areasthat have the potential for landsliding

These areas are determined by link some of the factors that contribute tolandsliding (such as steep slopes, weak geologic units that lose strength whensaturated or disturbed, and poorly drained rock or soil

These maps indicate only the relative stability of slopes; they do not make absolute predictions.

Landslide susceptibility maps can be considered derivatives of landslide inventorymaps because an inventory is essential for preparing a susceptibility map

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Landslide-hazad maps

describe the relative likelihood of future landsliding based only onthe fundamental properties of a locale or site $

+aps usually divide the study area into zones according todi erent levels of hazard to slope movement.

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They can also be called landslide hazard zonation maps$

These maps made ased on

1. statistical analysis of landslide distribution. the identi&ed controlling factors

!. based on variables such as rainfall thresholds$ slope angle$soil type$ and levels of earth4uake shaking.

"n ideal landslide hazard map sho#s not only the chances that alandslide may form at a particular place$ but also the chance thatit may travel do#nslope a given distance