GEOLOGY 470: FIELD EXERCISE 1 SPRING 2007-- BASIC SURVEYING AND COMPASS USE Objectives: 1. Determine pace, eye height, and height for use in rough surveying 2. Learn basic compass skills: reading, setting declination, taking bearings, determining vertical angles, use as a level 3. Learn how to use other simple surveying instruments: hand level, Suunto clinometer 4. Learn how to perform simple profile survey with hand level, tape and surveying rod 6. Learn basic techniques of measuring strike and dip 7. Develop field note-taking and data-collection skills Location: HSU campus Founders Hall - Van Matre Hall vicinity and campus to west and south. 1. Determination of eye height Method 1: Using carpenter’s level and surveying rod -- you will need someone to assist you with this. a. Set the surveying rod upright -- hold it vertically 6 in to a foot in front of you, with the rod rotated so that the numbers are nearly parallel to your line of sight and facing outward. b. Stand up straight -- don’t slouch. c. Have your assistant take the carpenter’s level and hold its top surface next to the side of your face at eye-height. d. Have your assistant level the carpenter’s level and read-- to the nearest 0.01 foot --where the top intersects the numbers on the surveying rod. e. Neatly record this as “eye height” inside the front cover of your notebook. Convert it to meters and enter that also. f. Use the level and surveying rod to determine your top-of-head height and record it inside your notebook front cover as “height”. Convert to meters and enter that also. Method 2: Using mark on wall and tape -- you will need someone to assist you with this. a. Stand sideways next to a wall. Have someone put a small pencil mark on the wall at your eye height. b. Measure the height of the mark with a tape to the nearest 0.01 ft. 2. Determination of your pace -- Founders Hall hallway Starting at 0 near the north basement door of Founders Hall, I have marked the hallway floor at 100, 200, 300, and 350 ft. You will use this to determine your pace, and to assess its variability. Your pace is not your ordinary walking or ambling-along step, nor is it some extreme, forced step. Instead, it is an attempt to smoothly step out a regular, consistent, comfortable distance with each step. My own surveying pace is slightly longer than my ordinary walking step. I consider it slightly forced -- but it is remarkably consistent. Practice in pacing improves your consistency. a. Set up your notebook for data collection. Starting on a fresh page, put the date at the top of the page. Then put in a header label, like “Determination of pace in Founders Hall basement”. Then lay out a table similar to that below: Determination of pace in Founders Hall basement distance, ft cumulative no of no of paces in distance in pace length, ft paces increment increment, ft 0 ----- ----- ----- ----- 100 100 200 100 300 100 350 50 300 50 200 100 100 100 0 100 total distance, ft total paces ----- ----- mean pace length, ft 700 ----- ----- Note: when collecting numerical or semi-quantitative data, it is good practice to do it using a table. First, it makes it easy to collect and extract the data, because it’s clearly organized. Second, and most important, it reminds you of what data needs to be collected at each site, and thus prevents you from making errors and omissions. The table should be laid out in your notebook before you begin collecting data. b. Starting at the “0” mark at the N end of the Founder Hall corridor, pace evenly and smoothly down the hallway; record the total (i.e., cumulative) number of paces you have taken as you cross the 100, 200, 300, and 350 ft tape marks; when you reach 350, turn around and count your paces back to the far end. The table will remind you where you need to record your cumulative number of paces. c. Determine the number of paces in each increment by successively subtracting your cumulative values. Divide the number of paces into the increment distance to determine your pace length. Round it to the nearest 0.1 ft. Comparing these numbers will give you an idea of the variability in your pace over short distances. (If you feel there was too much variability in your pace, then do it all over again, until you are satisfied.) d. Determine your mean pace length by dividing the total distance paced (700 ft) by the total number of paces taken (last entry in “cumulative no of paces” column. Enter this in your table, and also inside the front cover of your notebook. Convert it to meters and enter that as well. 3. Introduction to reading, setting, and use of Brunton compass, hand level, and Suunto clinometer for surveying Return to classroom. We’ll go through and briefly practice the following: a. reading of Brunton compass b. setting declination of Brunton compass c. taking bearings with Brunton compass d. taking vertical angles with Brunton compass e. using Brunton compass as a hand level f. adjusting and using a hand level, including reading surveying rod g. using Suunto clinometer to measure vertical angles 4. Field practice: measuring distances, bearings and vertical angles From here on, all the field measurements you make should be neatly and clearly recorded in your notebook. Everything must be labeled well enough that anyone looking at your notebook can figure it out. I suggest that you use table form wherever appropriate. Exercises in and adjacent to Founders Hall: a. Bearing of Founders Hall basement corridor 1. Stand in front of the midpoint of the Founders Hall south basement door. Determine the bearing to the midpoint of the Founders Hall north basement door. 2. Walk up the hallway to a point opposite the stairs. Stand above the middle line in the concrete that runs the length of the hall. Carefully align the compass so that its centerline lies along the floor line, pointing toward the N door. Record this bearing. How much does it differ from that you determined in step 1? Caution: there is metal rebar or pipe under the concrete floor which will affect the compass bearing if you hold the compass close to the floor or lay it on the floor. b. Founders Hall courtyard -- go upstairs to the courtyard door. 1. Vertical angle: Walk through the east courtyard door and stand on the first red concrete band running parallel to the long axis of Founders Hall. You can stand to either side of the door, but be sure you’re on the red band. Look west and determine the vertical angle to the topmost point of Kerr Tower. Record this. 2. Bearing: Cross the courtyard to the west door., but don’t go through it. Stand along center line of the west door take a bearing to the center line of the east door. Record this. 3. Distance: Pace the distance from the west door to the east door. Record your paces and convert it to feet. c. Length of the Redwood Bowl grandstand back -- pacing along Laurel Ave: Start at the north end of the concrete back of the grandstand where it abuts Laurel Ave (the road next to Founders Hall). Pace to the south end. Record the number of paces, and then convert it into the length in feet. We will later tape the distance and compare it with our estimates. Exercises in and adjacent to Van Matre Hall: d. Bearings and vertical angles taken from the Van Matre loading dock: Near the northeast corner of the loading dock is a small brass benchmark. Stand over (or very near) to the benchmark. 1. Bearing: Determine the bearing to the stadium lightpole at the SW end of the grandstand (see sketch below). 2. Vertical angle: Determine the vertical angle (slope angle) to the platform just below the lights on this lightpole. 3. Bearing: Determine the bearing to the stadium lightpole at the NE end of the grandstand (see sketch below). 4. Vertical angle: Determine the vertical angle (slope angle) to the platform just below the lights on this lightpole. Redwood Bowl grandstand SW NE stadium stadium lights lights VMH loading dock not to scale e. Bearings and vertical angles taken from the top of the stairway west of Van Matre Hall. Stand next to the concrete post immediately south east of the top of the stairs that lead downhill just west of Van Matre Hall. stairs concrete down post Van Matre Hall not to scale 1. Bearing: Determine the bearing to the stack of the pulp mill on the Samoa Peninsula in the distance. 2. Bearing: Determine the bearing to the top center of the Student Services Building skylight. 3. Bearing: Determine the bearing to the campus flagpole near the Library. 4: Vertical angle: Determine the vertical angle down to the topmost point of the western new campus gateway 5. Field practice: surveying a slope profile above Redwood Bowl with tape, hand level, and surveying rod. Reference: surveying handout The field site is on the hillslope above Redwood Bowl, next to the lightpost opposite the east basement door of Founders Hall. Two tapes will be stretched from the top of the slope next to the street to the pavement at the slope base. This will allows two teams to work at a time. The northern tape is Tape 1, the southern one is Tape 2.