[MTT45-P02] P-wave tomography beneath Greenland
Keywords:Seismic tomography, Greenland, Iceland plume, GLISN project
We inverted a number of P-wave arrival-time data of both local and teleseismic events, observed at 30 GLISN stations, to estimate a 3-D P-wave velocity (Vp) model beneath Greenland and surrounding regions. All of the GLISN arrival-time data are downloaded from the Bulletins of the International Seismological Centre. We used the seismic tomography method by Zhao et al. (2012).
In the polar region, if grid nodes are arranged on the basis of equatorial coordinates, distance between two adjacent nodes in the same latitude decreases as it gets closer to the pole. To overcome this problem, we converted our study region from the equatorial coordinates to the ecliptic coordinates. This scheme enables us to solve tomographic equations in quasi-Cartesian coordinates (e.g., Kobayashi & Zhao, 2004; Gupta et al., 2009; Takenaka et al., 2017). We set up a 3-D grid with a horizontal grid interval of 2° and a vertical grid interval of 15–30 km (at depths of 5–700 km).
The results of this study are summarized as follows.
(1) There is a prominent low-Vp anomaly beneath Iceland (depth < 500 km), which is related to the current Iceland plume.
(2) In the shallow mantle (40-250 km depths) beneath central and offshore eastern Greenland, Vp is relatively lower than those in the other inland areas of Greenland in the depth range, which may reflect the ancient motion path of the Iceland plume. This feature coincides with known basalt areas at central western and eastern coasts of Greenland.
Kobayashi, R. & D. Zhao (2004) PEPI, 141, 167–181.
Gupta, S., D. Zhao & S. Rai (2009) Gondwana Res, 16, 109–118.
Takenaka, H. et al. (2017) EPS, 69, 67.
Toyokuni, G. et al. (2014) Antarctic Record, 58, 1–18.
Zhao, D. et al. (2012) GJI, 190, 816–828.