ROAD DISTANCE AND ALL LANDSLIDE TYPES:

The road network examined included all the major and minor roads outside of the Liguanea Plain area shown on Jamaica, 1:50,000 metric sheets 13 and 18.
Limitations:
Due to the paper (non-stable) base maps from which we digitized the minor roads, there may be minor locational discrepancies between the road raster map and all other maps.
Some landslide types appear to correlate strongly with distance to roads.
In the granodiorite outcrop area surrounding Lawrence Tavern, all of the mapped active landslides (small circles) and active slide zones (small V's) occur very close to roads.

These slides occur in two settings:
Where the roads occupy ridge crests, active landslides are either downslope of the road grade, or on small roadcuts on the ridge crest itself.
Where roads occupy the valley bottoms the landslides occur upslope of the road.
In both cases it appears that human actions have caused the landslides, either by diverting concentrated roadside runoff onto slopes below the roads, or by cutting into steep sideslopes in the valley bottoms.
The landslide inventory contains 46 relatively small active landslides, and 341 zones of multiple small active landslides, with a combined area of 0.89km².
On an areal basis:
60% of these active landslides and zones (0.53 km²) occur within 90m of roads,
whereas the other 40% are spread rather uniformly across the terrain at distances of 90-2000m from roads.
In terms of landslides density: within 90m of roads there are 2368 active slide pixels out of a total of 368,823 pixels in the study area yielding a landslide density of 0.642%.
beyond 90m from roads there are 1611 active slide pixels out of a total of 1,558,129 pixels (this pixel total excludes the Liguanea Plain, where slopes are too gentle for landsliding).

THUS, DENSITY OF ACTIVE LANDSLIDES WITHIN 90M OF ROADS IS 6.23 TIMES HIGHER THAN THAT BEYOND 90M FROM ROADS.