Home | deutsch  | Department | Legals | Data Protection | KIT

Elastic full-waveform inversion of shallow seismics and applications to real data using time-frequency windowing

Elastic full-waveform inversion of shallow seismics and applications to real data using time-frequency windowing
sws:

14.01.2020

Referent:

Nikolaos Athanasopoulos (GPI)

This presentation will be given in english!
 
Full-waveform inversion of shallow seismic wavefields is a promising method to infer multiparameter
models of elastic material properties (S-wave velocity, P-wave velocity, mass density)
of the shallow subsurface with high resolution. Previous studies used either the refracted
P-waves to reconstruct models of P-wave velocity or the high amplitude Rayleigh waves
to infer the S-wave velocity structure. In this work we propose a combination of both wavefields
using continuous time-frequency windowing. We start with the contribution of refracted
P-waves and gradually increase the time window to account for scattered body waves, higher
mode Rayleigh waves and finally the fundamental Rayleigh wave mode. The opening of the
time window is combined with opening the frequency bandwidth of input signals to avoid cycle
skipping. Synthetic reconstruction tests revealed that the reconstruction of P-wave velocity
model and mass density can be improved. The S-wave velocity reconstruction is still accurate
and robust and is slightly benefited by time-frequency windowing. In a field data application we
observed that time-frequency windowing improves the consistency of multi-parameter models.
The inferred models are in good agreement with independent geophysical information obtained
from ground penetrating radar and full waveform inversion of SH-waves.