ES304 Self-assessment Test, Page 4

The questions in this test are similar to those in the sample paper for the end-of-semester assessment. However, the actual assessment will have few multiple-choice questions, and many single-word answer questions compared with this version.

If you have difficulties with any of the answers, don't hesitate to see or email me.

In each section, either choose answers with the radio buttons, or from the pulldown menus, then press the "submit" button to have the test scored and to get some feedback. At this time there is no record of your performance retained on the system.

 

Test 1

Test 2

Test 3

Test 4

Questions about rock and mineral properties will usually be one-word-answer style in the final paper:

First part

The choices in some of these menus may sometimes seem strange or unlikely—but most of them have been served up as answers in exams, so don't scoff too loudly!

 

1
 Which elastic wave is always recorded in a seismic survey?  
2
 Which direction of ground motion is usually recorded in a land seismic survey?  
3
 Why are seismic sections (reflection records) often presented with time as the vertical axis rather than depth?  
4
 The critical angle of refraction at a boundary, important in seismic refraction theory, depends on ...?  
5
 In a travel-time versus distance plot in seismic refraction, the slopes of the segments depend on the ...  
6
 In a travel-time versus distance plot in seismic reflection, the shape of the reflection curve (hyperbola) depends on the ...?  
 
 

Second Part

The next set of questions are based on this seismic refraction traveltime diagram.

 

1
 How many layers are evident?  
2
 Which symbol refers to the direct-wave response?  
3
 Which symbol refers to the maximum-velocity segment?  
4
 Having found the velocities, which symbol refers to the part of the diagram from which the layer-2 thickness might be found?  
5
 The velocity of sound in water is about 1500 m/s. What sound velocities might be observed in rocks?  
6
 What is the effect of lithification on seismic velocity?  
 
 

Third Part

Unfortunately, it is difficult to create neat questions based on seismic reflection images - but I'm working on it for next year!

1
 Seismic reflections arise from what kind of surfaces?  
2
 Seismic stratigraphy is an interpretation scheme which recognises that seismic reflection geometry is determined by...?  
3
 High-resolution seismic surveys are now repeated at regular intervals over some oil/gas reservoirs. Why?  
4
 Why has it been unusual to use seismic reflection methods in the search for mineral orebodies in hardrock environments?  
5
 Which of the following energy sources has not been used for seismic survey purposes?  
6
 The reflection coefficient at an interface depends on the change in the velocity*density product at the interface. What are typical values for reflectors in sedimentary sequences?