Gravity Survey Techniques and Concepts

The video tutorial introduces geophysical methods, focusing on the gravity method. It explains how changes in rock density affect gravity fields and how these measurements can be used to identify subsurface rock types. The tutorial covers gravity survey techniques, the importance of accurate field data recording, and the impact of earth tides on measurements. It provides detailed instructions on setting up and using a gravity meter and discusses the applications of the gravity method in finding subsurface resources and aiding archaeological expeditions.

What is the primary factor that the gravity method in geophysics relies on?

• Seismic activity

• Magnetic field strength

• Rock density changes

• Temperature variations

How does a rock with higher density affect the gravity field?

• It decreases the gravity field

• It has no effect on the gravity field

• It increases the gravity field

• It creates a magnetic field

What is the purpose of conducting a gravity survey?

• To map surface vegetation

• To analyze weather patterns

• To measure temperature changes

• To detect hidden rock contacts

What should be recorded in the field notebook during a gravity survey?

• Only the location

• Only the time of day

• Only the weather conditions

• Station number, reading, time, location, and field conditions

Why is it important to return to the base station during a gravity survey?

• To change the battery

• To account for solid earth tides

• To recalibrate the instrument

• To avoid bad weather

What is the first step in setting up a gravity meter?

• Adjusting the tripod height

• Turning on the instrument

• Leveling the gravity meter

• Entering the station number

What is the significance of the blue light on the gravity meter?

• It indicates a low battery

• It signals the start of measurement

• It means the device is malfunctioning

• It shows the device is off

What is the effect of solid earth tides on gravity measurements?

• They improve measurement accuracy

• They cause significant errors

• They have no effect

• They cause minor changes that need to be accounted for

How sensitive is the gravity method in measuring elevation changes?

• It can measure changes of 1 kilometer

• It can measure changes of 5 meters

• It can measure changes of 3 centimeters

• It can measure changes of 10 meters

What resources can the gravity method help to find?

• Minerals, water, and archaeological sites

• Only archaeological sites

• Only minerals

• Only water