Full Waveform Inversion Used to Recover Glacier Seismic Properties
E. Pearce, A. Booth, I. Jones and G. Stuart
Event name: 81st EAGE Conference and Exhibition 2019
Session: FWI Case Studies III
Publication date: 03 June 2019
Info: Extended abstract, PDF ( 404.47Kb )
Price: € 20
Glaciers preserve a climatic record in the seismic properties of firn, a transition-phase material as snow is compacted and densified into ice. The density gradient within the firn/ice column varies as a function of snow accumulation, thereby offering a link to climate change modelling. Due to the importance of various relationship between firn profiles and component glaciological processes, without the availability of seismic compressional wave velocity or real sample measurements from within the firn, it is not possible to recover values for the subsurface firn properties. Currently, Herglotz-Wiechert inversions are used to obtain estimates for the seismic velocity of the profile, but this technique is limited as it uses only the first-arrival travel times of wavelets and is unable to deal with velocity inversions that occur due to seasonal partial melting and refreezing. Additional information (e.g., density) must be obtained through empirical relationships rather than directly from seismic data. Full Waveform Inversion is able to offer an improved standard for glaciological seismic modeling through using the whole seismic dataset and subsequently improving the velocity:depth models for firn. This methodology presents an alternative technique to reconstruct glacier firn profiles, without the need to obtain core profiles, or rely upon empirical conversions.