Kenneth M. Cruikshank
Royse Debris Flow, Dodson, Oregon

Kenneth M. Cruikshank
Royse Debris Flow, Dodson, Oregon

This page shows the complete map of the Royse Debris flow deposit. The original map is about 2.5 metres long and was made at a scale of 1:250. The original field maps were pasted together, photocopied at 25% of the original scale, scanned in two sections at a resolution of 300 dpi, digitally pasted together. The image size was changed for the web page, and the resolution changed to 100 dpi. The whole map or either of the two sections of the map at 300 dpi can be downloaded. The scanned version of the map has a 20m UTM grid (NAD 27) overlayed on the image.

Links to map images

How the map was made

A Total Station was used to survey in 750 control points. At each control point location some flagging with the point number was left. The data from the Total Station was downloaded to a computer and plotted on ten overlapping 22"x17" sheets of paper. On each map sheet the relative location of points, point number, and elevation were plotted. The scale of the maps was 1:250 (1 cm represented 2.5 m).

The map sheets were then taken to the field. By standing on one of the field marks and looking towards other field marks major boulders (greater that about 1 m in diameter) and trees were drawn in. These major features could then be used as control points for mapping smaller features. This procedure was continued until the debris flow deposits had been completely mapped. When the features were all mapped, the contours were drawn. By using the elevation of control points and an Abney level the path of a contour across the mapped features was determined.

When all the sheets were mapped, they were joined to form a single map. This map was then field checked. The map presented here is the compilation of the field maps. The final map is currently being drafted.

At a later date the location of cross-section lines was determined and the lines surveyed with a Total Station. The sections were then drawn using the same technique as the map. The total station was also used to measure the height and slope of deposit in several places.

I did not draw every boulder! Boulders larger than 1m in diameter are correctly drawn. In the boulder fields I show the approximate size and packing of the blocks. Where there are small groups of boulders I usually represented the approximate size and number.

The map

All-Map-Small.jpg (49737 bytes)

Geology Department

Copyright © 1994-2015 · K.M. Cruikshank ·