Gravity and Geodesy

Description of lectures

The goal of this series of lectures is to evidence the benefit of recent techniques in gravimetry and geodetic positionning to the quantitative study of the Earth’s deformation and gravity field.

After a theoretical recall on the elastic or visco-elastic deformation of the Earth and induced gravity perturbations, we will first review the different types of ground gravimeters (spring, superconducting and absolute) as well as the space gravity techniques (GRACE, GOCE).

The time and space variable gravity will be investigated in relation to vertical motion of the Earth’s surface and (possible) associated mass transfer. We will focus on the hybrid gravimetry approach which consists in combining various types of gravimeters to study a specific problem related to surface or underground loading process (atmosphere, oceans, ice melting, continental hydrology, as well as gas, petrol, or geothermal reservoirs). We will also introduce the geodetic and gravity consequences of lunisolar tides, Earth rotation, volcanic activity and tectonics.

Aimed competence

To better understand the gravity changes in time and space. How to measure them to the best precision, how to treat the data and how to interpret the results and constrain the geophysical processes. To establish a link between gravity changes and vertical motion to infer mass transfers.

Prerequisite :

Theoretical Geophysics, elasticity.