Seismicity and Crustal Structure in North Greenland

Abstract

The crustal structure of Greenland varies greatly across the island. Previous studies have revealed that the region of North Greenland differs from the rest of Greenland, with a more shallow crustal thickness. Although this region is far from any plate boundary, earthquakes do occur. Locating these intraplate earthquakes can lead to a better understanding of the seismicity in the area. A challenge of understanding this region is the lack of seismic data available, as few seismic stations are in operation. However, four temporary stations were in operation from 2004 to 2007, and the data obtained gives new insights in the tectonic processes in the remote area. The velocity model used in this region today is a uniform velocity model for all of Greenland. Using the same velocity model for the entire island is not logical, as the crustal structure varies. It is thus beneficial to obtain a regional velocity model for North Greenland. The main objective of this thesis has been to find a new velocity model for North Greenland and this has been done using information about the crustal structure in the region. To obtain the knowledge needed, a joint inversion of receiver functions and apparent S-wave velocities has been performed. Shear wave velocity as a function of depth beneath the seismic stations was obtained and further implemented into a new regional velocity model. Earthquakes in the area were then relocated and the different locations were compared to locations obtained with the Greenland Velocity Model.