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The percentage of events occurring on each of these six conditioning factors was computed. This percentagewas subsequently applied to measure the weight of each conditioning factor for the susceptibility map production(e.g. 27% of Bedrock Slides occur on Shale. A weight of 27 was given to areas underlain by Shale bedrock).The same principle was applied to each landslide type combined with each conditioning factor.BedrockThe bedrock geology of the Bréifne area is rather complex. Numerous bedrock formations are present in thearea and bedrock type is a very important factor in susceptibility to landsliding. The percentage of eventsoccurring on each formation was calculated. A simplified bedrock geology map, containing nine bedrock typeswas selected for the analysis. The reasons for using a simplified map of nine bedrock types are listed below:• The bedrock formations are regionally distributed and would give higher weights in areas where eventsare concentrated.• A smaller number of bedrock types in the analysis will give a better distribution of weights.• Simplified bedrock geology types have similar structural, petrological and lithological characteristics.The percentages calculated for each landslide type are shown in Fig. 5.13. It should be noted that Limestone,Sandstone and Shale comprise the highest percentages of events.Fig. 5.13 Percentage of Landslides by Bedrock type.Soil parent material (Subsoil)Not all of the study area is covered by this thematic dataset. The Co. Leitrim dataset was not available for thisstudy. A total of 399 events are within the areas covered by Co. Sligo and Co. Cavan. These were categorizedas follows.• 66 Bedrock slides• 128 Peat slides• 55 Flow• 144 FallsOnly five soil parent material types were involved in the slide events in the area. Final calculations (Fig. 5.14)show bedrock slides and falls occurring mostly on areas where rock is at or close to the surface. Peat slidestake place in peat-covered areas, but, according to the IFS parent material map, some occurrences arehappening in non-peat covered areas. This may be explained by the fact that only those areas with peat of 1m+in depth are mapped as peat covered, and slides may occur in areas of thin peat. Flows chiefly occur on rockat or near surface. This is attributable to the fact that 60% of the flows occur in areas dominated by shale, orlimestone and shale, and these are bedrock types susceptible to flowing when water saturated.54