TWO SETS OF MOUNTAIN LINEARS IN SOUTH WESTERN B.C

Since the early 1980’s mountain linears or “sackungen” have been identified in increasing numbers in South Western B.C. These features include tension cracks, anti-slope or obsequient scarps, ridge-top trenches and double ridges (“dopplegrate”). Potentially linked to deep-seated deformation in the rock slopes, some authors have suggested that certain linear features represent an incipient condition which may evolve into rapid rock failures.

Data for two linear sets are presented. Brohm Ridge linears near Squamish, B.C. have been previously identified and mapped. New data from this study includes the spatial distribution of geotechnical properties of the rock units that the linears are developed within. In addition, the location of the linears with reference to specific geomorphological features is examined. The linears at Mount Mercer in the Chilliwack Valley, B.C. are ,to the author’s knowledge, previously undescribed within the literature. New data regarding geotechnical properties of the bedrock as well as morphological mapping is presented. The field data from each study site will be used in future analysis of linear formation using geomechanical modeling.

The large amounts of field data are organized using a GIS. In addition, the field data is combined with digital terrain models (DTMs) for visualization and further geomorphological investigation. Finally, the GIS provides the geostatistical tools required to evaluate the spatial distribution of the geotechnical properties of the bedrock at each study site. To facillitate data collection, a database application running on a hand held computer has been developed incorporating a MS Access database and the ESRI geodatabase data model.