How To Use A Brunton Compass

THE PARTS OF A BRUNTON COMPASS

WHAT IS DIP AND STRIKE

MEASURING STRIKE AND DIP

Measuring strike:

We volition begin by taking the strike of a bedding plane. For these measurements we volition use a Brunton compass like the one yous meet in the pictures above. In order to measure the strike, place the side or edge of the compass confronting the plane of the outcrop. Sometimes it is easier to put your field volume against the outcrop and and then the compass against the book to get a smoother and/or a larger surface. Now, rotate the compass keeping the lower side border of the compass fixed, until the bulls-eye level chimera is centered (the round tube; not the long narrow 1). When the bubble is centered, the compass is horizontal against the aeroplane and parallel to the line of strike. Now, with the bulls-eye bubble centered, tape the number that either end of the compass needle is showing.

In other words:

Place the bottom Edge of the compass flat confronting the plane of interest.

Adjust the compass orientation, making sure the bottom edge is always flat against the plane, until the air bubble in the "Bull's eye level" is centered.

Read either end of the compass needle to obtain the value of strike.

Measuring Dip:

To measure the dip of the bedding airplane, take your compass and put its side against the rock so that it points in the same management as the line of dip (The dip line is perpendicular to the strike line). Motility the clinometer until the clinometer level bubble is centered. As we did when we found the strike, record where the white tipped cease of the clinometer needle is pointing. Note the degrees and the direction. Recall that the dip direction MUST always be perpendicular to the strike management (e.grand., a strike of 40° could only dip to the SE or NW, never NE or SW)

In other words:

AFTER you determine strike, rotate the compass xc°.

Place the SIDE of the compass flat confronting the airplane.

Suit the lever on the dorsum of the compass until the air bubble in the "Clinometer level" is centered.

Read the dip directly from the calibration in the compass.

Measuring Trend:

The "Fold-out pointer" should betoken downwards-plunge.

Concord the compass horizontally To a higher place the aeroplane (the bubble in the "Balderdash'southward eye level" should exist centered).

Look directly down through the "Slot" in the "Fold-out pointer".

Rotate the compass, keeping it horizontal, until the slot is parallel with the line to exist measured. (the line should run straight downwardly the middle of the slot).

Read the North cease of the compass needle to obtain the value of trend.

Measuring Plunge:

Place the bottom EDGE of the compass flat on the line (the border should be parallel to the line).

Make certain the compass is vertical.

Suit the lever on the back of the compass until the air bubble in the "Clinometer level" is centered.

Read the plunge straight from the scale in the compass (the same fashion y'all read dip).

The images have been copied from: http://courses.geo.ucalgary.ca/glgy203/images/sd.htm.