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The accompanying map, located on the back page of Section A, shows ground contours at 5 metre vertical intervals - Leaving Cert DCG - Question C-1 - 2014
Question C-1
The accompanying map, located on the back page of Section A, shows ground contours at 5 metre vertical intervals. (a) On the drawing supplied, draw a vertical secti... show full transcript
Worked Solution & Example Answer:The accompanying map, located on the back page of Section A, shows ground contours at 5 metre vertical intervals - Leaving Cert DCG - Question C-1 - 2014
Step 1
On the drawing supplied, draw a vertical section (profile) on the line AB.
Answer
To create the vertical section along line AB, follow these steps:
- Measure Heights: Using the map supplied, measure the height at various points along line AB based on the 5-metre vertical intervals indicated by the contours.
- Draw Horizontal Lines: For each measured height, draw horizontal lines across the section to represent the contour levels. This forms the baseline for plotting the vertical profile.
- Project Intersections: Identify the intersections of line AB with the contour lines and project these points vertically down to the horizontal lines.
- Outline of Profile: Connect the projected points to create the vertical profile, ensuring to represent steep and gentle slopes accurately.
Step 2
Determine the strike and dip of the stratum.
Answer
To find the strike and dip of the stratum defined by points C, D, and E, proceed as follows:
- Join Points in Plan: Draw a line on the plan connecting points C, D, and E to visualize the orientation of the outcrop.
- Draw Triangle in Elevation: Construct a triangle to represent the elevation changes between points C, D, and E, which helps visualize the slope of the stratum.
- Determine Horizontal Line in Elevation: Establish a horizontal line in elevation based on the lowest point of the triangle to measure the angle appropriate for the dip.
- Strike in Plan: The strike can be defined as the direction of a horizontal line intersecting the inclined surface of the stratum. Measure the angle from north to get the strike direction.
- Viewing Direction for Dip: Establish a viewing direction that will help visualize the angle of dip from the horizontal.
- Determine Dip: Calculate the dip by measuring the angle between the horizontal line in elevation and the inclined surface of the stratum. Report this angle to describe how steeply the stratum descends.