SUMMER 2003GEOHAZARDS COURSE AT UWI, MONA - page 104

Prepared and compiled by Rafi Ahmad, Unit for Disaster Studies,
Department of Geography and Geology,
University of the West Indies, Mona, Kingston 7, Jamaica

LANDSLIDE INVENTORY:
Field investigations and compilation of landslide inventory map followed the procedures outlined in " Landslides Investigations and Mitigation, Special Report 247, National Academy Press, Washington" edited by A. K Turner and R.L. Schuster (1996, Part 2: investigations).
The procedure comprised the following steps:
(i) Stereoscopic interpretation of vertical aerial photographs (1961 Series, scale 1:50K and 1991-92 Series, scale 1:15K, Survey Department, Jamaica),
(ii) Recognition of anomalous topographic features indicative of landslide landforms on aerial photographs and topographic maps (Jamaica Survey Department Sheets 13 and 18, scale 1:50K, Metric Edition),
(iii) Compilation of landslide data from previous investigations including information provided by Mines and Geology Division (Section 2.3),
(iv) Field verification of the above data , - and
(v) Compilation of the landslide inventory map and digitization of data.

Landslides were subdivided into the groups, each identified by a unique mapping symbol following the methodology of Weiczorek (1988).
We use the term "scarp" to indicate the entire source area of a landslide, not just the headscarp, which is the more typical meaning. Thus, our label "Scarp" is synonymous with the entire landslide feature, its source area including the scar and the landslide deposit.

A Landslide inventory of the area includes:
1) Active landslide (small individual slide, 5 -10m wide)
2) Active landslide zone (zones of small slides, up to 30m wide)
3) Scarp-Definite
4) Scarp-Probable
5) Scarp-Questionable
6) Deposit-Definite
7) Deposit-Probable
8) Deposit-Questionable.

The landslide inventory of KMA contains 2,321 landslides (Table 1).
Landslides are subdivided into :
(a) - active (landslides, n=46; zones, n=341),
(b) - scarps (definite, n=613; probable, n=958; questionable, n=340), - and
(c) - deposits (definite, n=18; probable, n=4; questionable, n=1).

Landslides cover 19.786 km 2, or 3.57% of the entire study area.
Excluding the Liguanea Plain, landslides cover 4.77% of the mountainous areas.


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