Physical Geodesy Overview

Play an AI-generated podcast conversation about this lesson

What is the geoid primarily used as a model for?

Describing the Earth's gravity field (correct)

Calculating depths of earthquakes

Defining the Earth's topography

Modeling the Earth's curvature

How does the geoid differ from the Earth's actual shape?

It is perfectly spherical

It does not coincide with the mean sea level

It is affected by tides and oceanic currents

It is irregular due to Earth's rotation and topography (correct)

Why is the geoid described as an 'equipotential surface'?

Because it is greatly affected by gravity (correct)

Because it coincides with the ocean surface

Because it defines zero elevation

Because it has an irregular shape

Which factor contributes the most to the irregular shape of the geoid?

Earth's rotation and topography Signup and view all the answers

How do surveyors use the geoid in their calculations?

To extend imaginary lines through continents Signup and view all the answers

What role does physical geodesy play in geodesy?

Modeling the Earth's gravity field Signup and view all the answers

What geometric shape represents an ellipsoid in terms of its cross sections?

Circles Signup and view all the answers

In an ellipsoid, how many principal semiaxes are there?

Three Signup and view all the answers

What geometric shape results when the principal semiaxes of an ellipsoid are equal?

Sphere Signup and view all the answers

Which field of study utilizes measurements of the Earth's gravity field to deduce the shape of the geoid?

Physical Geodesy Signup and view all the answers

What does the geoid represent?

The equipotential surface at mean sea level Signup and view all the answers

What happens to the ocean surface if it were at rest according to the text?

It coincides with the geoid Signup and view all the answers

What is the main application of gravimetry in the oil and gas industry?

Determining subsurface density structure Signup and view all the answers

Why is gravimetry considered advantageous over other techniques in the oil and gas industry?

It is inexpensive Signup and view all the answers

What is a common use of gravimetry in geotechnical engineering projects?

Determining tunnel layouts Signup and view all the answers

What does the geoid approximate?

Mean sea level Signup and view all the answers

What fundamental difference exists between the mathematical geoid model and the real object?

The geoid approximates mean sea level Signup and view all the answers

Why is the shape of the ellipsoid different from the real shape of the earth?

Because it is a mathematical approximation Signup and view all the answers