UGA Geophysics group uses earthquakes from Indonesia to image Earth's crust under Georgia.

Devon Verellen, Erik Alberts, Gustavo Larramendi, Horry Parker, and Rob Hawman just published a paper in the journal Geophysical Research Letters that studied the nature of the boundary between the tectonic plate beneath the southern Appalachians and the underlying, more fluid mantle. They used echo soundings to determine the depth and physical characteristics of major layers. Hawman states "Our strategy was to use seismic waves generated by earthquakes on the opposite side of the planet as an energy source. We see a major transition at depths of 120–135 km that we interpret as drag‐induced flow just beneath the plate. We also see evidence for a thickening of Earth's crust beneath the highest elevations of the southern Appalachians that suggests that these very old mountains are in gravitational equilibrium." 

The main goal of this work was to study the nature of the boundary between the tectonic plate beneath the southern Appalachians and the underlying, more fluid mantle. We used echo soundings to determine the depth and physical characteristics of major layers. Our strategy was to use seismic waves generated by earthquakes on the opposite side of the planet as an energy source. We see a major transition at depths of 120–135 km that we interpret as drag‐induced flow just beneath the plate. We also see evidence for a thickening of Earth's crust beneath the highest elevations of the southern Appalachians that suggests that these very old mountains are in gravitational equilibrium.

(DOI: 10.1029/2020GL089648)