Current Research

I am using body wave tomography to study the mechanisms of continental collision. I work with Keith Priestley, Frederik Tilmann (now at GFZ) and Steve Roecker (at Rensselaer Polytechnic Institute ) and Ross Heyburn (AWE Blacknest). I have been looking at an area on the northeastern margin of the Tibetan Plateau, which includes the Qiangtang and Songpan-Ganzi terranes as well as the Kunlun Shan and the Qaidam basin. I have constructed tomographic images of P- and S-wave velocities in the crust and upper mantle beneath this part of the plateau. I explored the influence of the starting model on these inversions, and used three different starting models for these inversions, using a combination of results from recent surface wave investigations and Moho depth maps from receiver function studies. I found that the incorporation of surface wave models considerably aids our interpretation of the body wave based images. 

Next Phase

The next phase of my project involves carrying out joint surface wave and body wave inversions. Teleseismic regional tomography is most sensitive to lateral velocity contrasts, and in particular cannot resolve layer averages or very long range velocity variations; neither can it image variations in thickness or properties of the crust. Furthermore, the depth resolution of body wave tomography is relatively poor. In contrast, surface wave tomography has good depth resolution (down to 250-300 km depth), but tends to smear short wavelength horizontal anomalies. By combining these different observations, we hope that these observations will prove to be complementary, and will produce sharper tomographic images. 

My PhD is funded by NERC with additional CASE sponsership from AWE Blacknest.

Submitted Publications 

P- and S- body wave tomographic model of the northeastern Tibetan Plateau and its margins with additional constraints from surface wave tomography
Ceri Nunn, Steven W. Roecker, Frederik J. Tilmann , Keith F. Priestley, Ross Heyburn, James Mechie, Eric A. Sandvol, James F. Ni, Yongshun John Chen , Wenjin Zhao, and the INDEPTH IV and ASCENT Team
Submitted to Geophys. J. Int. 

Conference Proceedings

P-wave tomographic structure of NE Tibet
Nunn, C, Tilmann, F. J., Roecker, S. W., Priestley, K. F, Heyburn, R and the INDEPTH IV and ASCENT Team
EGU, 2011, poster

Abstract

P- and S-wave tomographic structure of NE Tibet
Nunn, C, Tilmann, F. J., Roecker, S. W., Priestley, K. F, Heyburn, R, Mechie, J., Sandvol, E. A., Ni, J. F., Chen, Y. J., Zhao, W., and the INDEPTH IV and ASCENT Team
American Geophysical Union, Fall Meeting 2011, abstract #T43A-2302, poster

Abstract


Last updated on 27-Sep-12 14:27