LANDSLIDE IMPACT IN KINGSTON METROPOLITAN AREA (KMA):

Landslides have occurred for thousand of years in KMA and rank high on the list of geohazards that affect this area.
For the inhabitants of KMA, landslide hazard is a major constraint on land use.
Unstable slopes pose a continuous threat to their lives, property and the infrastructure, especially the road network. Landslides have affected both the natural slopes as well as those modified for human use and have caused significant damage to property and infrastructure.
Some of the residential areas of Kingston and St.Andrew are located on marginally stable slopes that were disturbed by pre-historic and historic landslides.
For example, the Geological Map of Kingston area prepared by the Geological Survey of Jamaica (1994 b) shows that between Papine and Jacks Hill landslips cover an area of some 0.8 km² (80 hectares), or approximately 16.89 % of the total slope area of 4.75 km².
Many of these ancient landslide scarps and their deposits are concealed by vegetation and have been extensively modified by both natural processes and human interventions.
These areas may remain stable for a long period of time until natural processes (e.g. intense rainfall) and/or human interference (e.g. construction activity) disturb the slope stability conditions.
An excellent example of this is provided by the widespread occurrence of debris and mudflows in the Jacks Hill area that were triggered by the rainfall associated with 1973 tropical storm Gilda, and more recently, the rainfall during 20th October to 3rd November 1998.
Several retaining walls were also destroyed in this area as a consequence of the failure of backfill.
The spectacular submarine landslide triggered by the MMI X, June 6, 1692, earthquake that destroyed the buccaneer town of Port Royal best illustrates the impact of landslides on the coastal environment of the capital city of Jamaica.
This earthquake, as well as the M 6.5 Kingston earthquake of 1907, caused localized submarine slumping-related tsunamis and liquefaction in the coastal areas and also triggered widespread landslides in eastern Jamaica including the Port Royal Mountains.
While not every landslide that has occurred in KMA since the time for which historic records are available can be classified as catastrophic, the cumulative damage from many small-scale rainfall induced landslides is more serious than that of a single major slope failure.
It has been estimated that during the period 1910 to 1965, for which published data are available, some 7. 3% of the total expenditure of the Public Works Department of the Government of Jamaica, accounted for damage-repair costs related to landslides and flooding - and this trend continues (Naughton, 1984).