Sub-module 2.4 A Lectures # 17-21 LANDSLIDE HAZARD
(MODIFIED FROM: Jerry DeGraff, Ahmad, McCalpin )
The geological processes and natural forces that have created the present-day landscape on the island of Jamaica are the same that make it most vulnerable to natural hazards.
Landslide activity is one of the principal geomorphic processes through which hillslopes evolve.
These features represent locations where the resisting strength of rock and soil masses that make up a slope are overcome by the force of gravity which is continuously acting on a slope to move slope materials downslope.
Every location on a hillslope can be considered as a part of an on-going tug-of-war between the driving force of gravity and resisting forces due to materials that constitute a slope.
Both natural processes and human modifications of slopes can change this balance in the favour of gravity.
The strength of the slope materials is reduced due to internal changes (weathering, seepage erosion, ground water changes etc.),
while stresses on slope can be increased as a result of external factors (steepening of slopes through excavations, loading of slopes etc.).
The landslide triggering mechanisms include :
rainfall associated with tropical storms and/or earthquakes.