Question and Discussion

7.0 QUESTION QUESTION AND DISCUSSI DISCUSSION ON

(1) Give two (2) methods to draw the structural geology data and discuss based on what situation we choose that method (each method).

a)

Cross Section Techniques

This kind of technique is generated from geological maps and can be seen as vertical slices through a map area showing a profile view of subsurface structure. ross!sections are either trial sections" drawn to solve structural problems" or are drawn to supplement a fair copy map or illustrate a report. They are also drawn to site boreholes in the search for a lost aquifer or ore body. The geological cross sections drawing are not a small or trivial undertaking and methods for their generation have become sophisticated. This is because we are trying to make interpretations about the geometry of features (e.g. bedding" faults) at depth on the basis of surface geometries. #ome aid in this regards may e$ist in the form of borehole or  geophy geophysic sical al data. data. %oweve %owever" r" this is often often the e$cept e$ception ion and skill skills s should should be tuned tuned for cross cross sectio section n construction without such subsurface information.

30°

& cross section of the map

b)

'ip and strike of a bedding plane

Streonet Techniques

n this technique" all circles on the sphere plot as circles on the plane" making it easier to construct the proection. The proection is conformal" meaning that angles and small shapes on the sphere proect are true on the plane. *ach proection represents the important data in the map so the contour can be made. #mall regions on the sphere proect true on the plane" making the stereographic a good map proection for small areas" but radial distortion increases away from the tangency point.

(2) *$plain the type of geological structure structure plotted in the stereonet stereonet with the aid of diagram. diagram.

 &ccording to the geological structure that has been plotted in this e$periment by the stereonet" we can determine the earth geographysuch as the hill" mountain and many other earth surface that represent by the contour. There are several datas that required in this e$periment such as the dip directions and dip angles in the geological map. t can be plotted on polar stereonet which dip direction and dip degree is being used. n this e$periment" we have 12+ datas to be plotted. ,sing the tracing paper" we have plotted 12+ dotes on it which is requires focus on the plotting work or else the result will be slightly unaccurate base on the datas. &fter the datas were plotted" there are groups of plotted dotes then calculated. &fter that" another  tracing paper was used to plot the contour. -y using this kind of plotting contour method" the slope stability and the failure of slope can be determined. The failure of slope is whether planar" wedge" circular or toppling.

() *$plain the methodology to determine the discontinuities survey data. 'iscontinuities can be defined as any form of mechanical breaks or fractures within a rock mass which can cause tensile strength across the fracture planes to approach /ero or even lower. To determine the discontinuities survey data" we need to collect some data and assuming some parameters in order to measure he discontinuities. To collect such data" the best tool is the geological compass. ollecting datas by using geological compass is a better method because it can save a lot of time while using other method that wasting much time on calculation to find the data needed. There are another kind of method to determine the discontinuities which called #canline #urvey. -efore conducting this ob" there is some preliminary preparation before we do the right procedure smoothly. The discontinuities survey data sheet is prepared which is containing all of the data that we need to measure on the site.