Geophysics Department Seminar - Aurélien Mordret: Exploring the Greenland Cryosphere with Ambient Seismic Noise Interferometry
- Thursday, Oct 11, 2018 12:00 PM
- Mitchell 350/372
- Faculty/Staff, Students, Alumni/Friends, Members
- Geophysics Department
Ambient seismic noise methods have been around for more than a decade now but they have not run out of applications yet. Both imaging and temporal monitoring of seismic velocities techniques bring invaluable information on the structure and dynamic of the Earth crust and some environmental phenomena affecting it.
This is particularly true for remote and seismically quiet areas such as Greenland. I will present two studies of the Greenland crust using ambient noise correlation methods. In the first one, I monitored the Greenland ice-sheet seasonal mass variations by measuring the loading-induced pore-pressure variations in the crust as seen through the prism of shear-wave speed temporal fluctuations. In the second study, I used the Rayleigh waves contained in the noise correlations computed between each pair of sensors from the GLISN seismic network to image the crustal and uppermost mantle structures associated with the Iceland hotspot track beneath Greenland. I observed high velocity anomalies linked to magmatic intrusions in the middle crust and a remnant low velocity/High temperature/low viscosity anomalies in the upper mantle at the location where the Iceland hotspot was the most active 60 Ma ago.