Study Questions

Earth Sciences Department

King Fahd University of Petroleum & Minerals

Electric Methods Gravity and Magnetic Exploration SeismologySolid Earth GeophysicsEarthquake Seismology

Condo Hotel
Southern Living Magazine Subscription


  1. What is the approximate value for the acceleration of gravity?
  2. How do we know that the interior of the Earth must be composed of rocks denser than those on the Earth's surface?
  3. What causes the Earth's oblateness?
  4. Define:
  • spheroid
  • geoid
  1. What is the name of the formula used to calculate the theoretical value of "g" at any latitude?
  2. In what two ways may one measure the actual value of g at a particular location?
  3. What is a gravity anomaly? a positive gravity anomaly? a negative gravity anomaly?
  4. Name the reasons why the actual value of g measured at a particular place is not the same as the theoretical value.
  5. What corrections are applied to:
  • "correct" actual values of g to remove that portion due to the mass between sea level and the elevation at which g was measured,  correct actual values of g to remove the effects of nearby mountains and valleys,
  • correct actual values of g to sea level?
  1. Define:
  • Free Air anomaly
  • Bouguer anomaly
  1. Which of the three most commonly applied corrections is the least important and is often ignored?
    If not ignored, how is the corrections usually made? Why is the topographic correction always added to the measured value?
  2. What are the characteristic values for Bouguer Anomalies in the following places?
  • mountain regions
  • continental shields
  • oceans
  1. How are positive anomalies produced? negative anomalies?
  2. Describe Pratt's and Airy's concepts of isostasy. Which is probably correct?
  3. What is another name for small scale anomalies which remain after regional anomalies are removed?
  4. Outline the procedure for interpreting gravity anomalies.
  5. What kinds of anomalies (sign and shape) would be produced by the following geologic features?
  • salt domes
  • sedimentary basin
  • mass of granite
  • ultramafic mass
  • buried ridges and valleys
  • anticlines
  • synclines
  • oceanic trenches
  • oceanic ridges
  • fault
  • buried stream channel
  • continental crust/oceanic crust boundary
  1. What is the "International Gravity Formula"? What does each term in the definition signify? Explain what the formula is used for.
  2. Define Free Air, simple Bouguer and complete Bouguer anomalies. What is the significance of each term in the definitions?
  3. Explain how the three anomalies behave on a regional scale and on a local scale. Which anomaly is preferred for exploration? Explain why.
  4.  Explain several ways to separate regional and residual gravity fields. What are the advantages and disadvantages of each method? In what circumstances would each be preferred?
  5.  Compare and contrast gravity methods with other geophysical methods for solving various problems such as...
  6.  Explain how to convert gravity meter readings into gravity anomalies relative to a base station. What data do you need in addition to the meter readings?
  7. Write a good original question to add to this list.


King-Fahd University of Petroleum and Minerals, P.O.Box:1946, Dhahran 31261, Saudi Arabia, Telephone: (966) (03) 860-1661  Fax : (966)(250) 860-2595