skip to primary navigationskip to content
 

E421: Bridging the Moho: Joint inversion of seismic body and surface wave data for crust and lithospheric mantle structure (Lead Supervisor: Nicholas Rawlinson, Earth Sciences)

Supervisors: Nicholas Rawlinson (Earth Sciences) and Robert (Bob) White (Earth Sciences

Importance of the area of research:

Seismic imaging methods such as reflection profiling, wide-angle imaging, surface wave tomography and teleseismic tomography have played a crucial role in advancing our understanding of the architecture and physical properties of the lithosphere. However a key challenge that remains is to unravel the structural relationship between the lower crust and adjacent lithospheric mantle; this is essential if we are to properly understand fundamental Earth processes such as continental growth, subduction, rifting, volcanism, delamination and mineralisation. Traditional imaging methods have struggled to address this issue due to the need to account for the Moho and the lack of datasets which can resolve both crustal and upper mantle structure. While several recent advances, including the joint inversion of multiple datasets and ambient noise imaging, have helped to address these challenges, considerable work is still required if we are to achieve a truly integrated view of the lithosphere.

Project summary:

The aim of the project is to develop and apply methods for the joint inversion of body and surface wave data in order to image structure throughout the full thickness of the lithosphere, thereby achieving a greater understanding of the processes which shape the crust-upper mantle system. Active and passive source body wave data will be utilised in addition to surface waves from teleseismic events and the ambient noise wavefield. Joint inversion of these datasets for 3-D seismic velocity and interface structure will be carried out. The new methodology will be applied to datasets from Australia, Borneo Malaysia and Iceland.

What the student will do:

The student will work with the two supervisors in order to extend existing methodology, which allows for the joint inversion of multiple body wave datasets, to include constraints from surface waves. Although inversion for 3-D variations in seismic wavespeed is now standard, the inclusion of potentially complex interface surfaces is not, and one of the challenges will be to successfully integrate both body and surface waves into what is necessarily a sophisticated parameterization and inversion framework.  This will involve extensive code development and testing of advanced geophysical inversion methods. The student will also be involved with the processing of seismic data, application of the new method to pre-existing datasets, and interpretation of the results. Suitable datasets are already available from eastern Australia and Iceland, and the student will have the opportunity to assist with the collection of new datasets in Iceland and North Borneo.

Please contact the lead supervisor directly for further information relating to what the successful applicant will be expected to do, training to be provided, and any specific educational background requirements.

References:

Greenfield, T., White, R. S. & Roecker, S. The magmatic plumbing system of the Askja central volcano, Iceland as imaged by seismic tomography, Journal of Geophysical Research, 121, doi: 10.1002/2016JB013163 (2016).

Rawlinson, N. & Fishwick, S., Seismic structure of the southeast Australian lithosphere from surface and body wave tomography. Tectonophysics, 572-573 (2), 111-122 (2012).

Rawlinson, N. & Urvoy, M., Simultaneous inversion of active and passive source datasets for 3-D seismic structure with application to Tasmania. Geophysical Research Letters, 33, L24313 (2006).

Follow this link to find out about applying for this project.

Other projects available from the Lead Supervisor can be viewed here.

Filed under: