Tentative laboratory topics
Aug. 22: Pendulum measurement of "g" Week 1 homework
Aug. 29: Gravity - a function of elevation (Field).
Download gravity data here
No lecture or lab on Labor Day. There might be room for volunteers to assist with a field project.
Sept. 12: Field gravity measurements (Field).
Gravity data: locations, elevations and dial
readings. Do not use GPS elevations, use values next to dial readings.
Image (click to enlarge): New gravity stations (yellow triangles) on LIDAR
data, color classified at 2-foot intervals. Blue is low, dark brown is
high, with green and yellow intermediate. Can you pick out any geographic
features?
You have everything you need to calculate the simple Bouguer gravity values for the 4 new stations, please use the 1930 IGF and 2,670 kg/cubic meter for your reductions.
Previously collected gravity data and other useful stuff
Sept. 19: Gravity data reductions and interpretation (computer lab).
Sept. 26: Field magnetometer survey.
Oct. 3: Magnetic data processing (computer lab)
Magmodel - a
spreadsheet that calculates the total field anomaly due to a buried dipole.
DATA - downloaded last
Wednesday. "Save as" to your storage media and make a series of Surfer
maps as per instructions. Remember, make one contour map using all data of
each kind (top sensor, bottom sensor, gradient - 3 contour maps in all) and a
second contour map of each type after you have removed high-amplitude spikes
(positive and/or negative) from the data (not just from the grid).
Note: a spike on the lower sensor does not necessarily mean a spike on the top
sensor (although the gradient will spike - after all, gradient is simply top
minus bottom divided by distance between them - or is it bottom minus top?
Another issue: Top sensor data should be a lot smoother than bottom sensor data. Is it possible that the top/bottom are reversed? The last profile may have lots of noise on the bottom sensor if the metal decorations on the operator's belt were magnetic.
See this page for an example of a magnetometer report. Links on the page direct you to figures.
Oct. 10: Ground-penetrating radar (Field)
Oct. 17: Autumn Break – no lecture or 4610 lab, probably will have field research expedition (willing workers welcome!).
October 24: Synthetic seismograms. Spreadsheet that does convolution. Note that one sheet generates a wavelet - you can change the frequency, then copy and 'paste as' values into column A on the Series page. Please allow the macros to be activated, else the program will not run. Put your reflection coefficient time series in Column B, then hit the Run button for the convolution, which should appear in Column C. Set up to graph C(t) as a function of T (this may take some copying/past or generating cell addresses on the third page - insert additional pages for the graph if necessary). My guide has not been updated to reflect improvements in the spreadsheet so, where conflicts exist, use the wavelet from the spreadsheet rather than the wavelet from the handout. Also, compare and contrast synthetic seismograms using low-frequency and high-frequency wavelets, once reflections from the base of the thin bed begin to seriously degrade the reflection from the top of the page. Do not use frequencies greater than 100 hz or less than 10 hz.
Oct. 31: Reflection seismograms, interpretation.
Nov. 7: There will be no lab on the afternoon of Nov. 7 (Midterm - take-home, open book, distributed Monday at 9 AM, due Tuesday at 10 AM).
Friday, Nov. 11 Veterans' Day - NOTE!! Seismic refraction - our annual Veterans' Day turkey shoot - we spend all day at a remote field research site - TBA.
Nov. 14: Seismic refraction interpretation (computer lab)
Seismic refraction
interpretation software
Nov. 21: Lecture AM, perhaps a video for lab.
Nov. 28: Earthquake seismograms I
Dec. 5: Earthquake seismograms II
FINAL EXAM (if needed): Tuesday, December 13, 10:15 – 12:15.
Formal report or short report?
ORGANIZE AND USE YOUR TIME PROPERLY. Laboratory reports take a lot of time. You cannot hope to complete an entire report (data analysis to written draft) overnight. I cannot do that, and I know all of the tricks and shortcuts. Your data analysis and graphs should be completed within 48 hours of the fieldwork, and a rough draft should be completed no less than 48 hours prior to the deadline. If you seek help with data processing on a Monday morning and the report is due that Monday afternoon, it will be clear to me that you did not begin report preparation according to instructions.
You should put this draft aside over night, reread it carefully and critically, and pencil in editing changes right on the hard copy. Did you really mean what you wrote, and did you write what you need to communicate? Is each graph necessary and does it have an informative caption? Is it properly numbered? Is your abstract informative and concise? At this point, rewrite your report and make those necessary revisions. Then FILE YOUR FIRST DRAFT (keep it handy, do not throw it away). Logjams will occur if everyone delays report writing until the last minute. I am often unavailable the day before a report is due - you should come to me with questions while doing that first draft! In the professional world, reports are needed so that decisions can be made, bids submitted, plans finalized and budgets drafted. A late report may require a client to proceed without benefit of what we were supposed to be able to tell him, for which he might sue for failure to fulfill the contract. It is your responsibility to make timely use of the resources at your disposal - including your time.
Late reports distract you and me from concentrating on current topics. This is not efficient.