Abstract
The Earth, in large portions, is covered in oceans, sediments, and
glaciers. High-resolution body wave imaging in such environments often
suffers from severe reverberations, that is, repeating echoes of the
incoming scattered wavefield trapped in the reverberant layer, making
interpretation of lithospheric layering difficult. In this study, we
propose a systematic data-driven approach, using autocorrelation and
homomorphic analysis, to solve the twin problem of detection and
elimination of reverberations without a priori knowledge of the elastic
structure of the reverberant layers. We demonstrate, using synthetic
experiments and data examples, that our approach can effectively
identify the signature of reverberations even in cases where the
recording seismic array is deployed in complex settings. For example,
using data from (1) the Alaska amphibious community seismic experiment
(AACSE), (2) Earthscope transportable array stations deployed in the
sedimentary basin around the Mississippi embayment, and (3) stations
deployed on ice-sediment strata in the glaciers of Antarctica. The
elimination of the reverberation is implemented by a frequency domain
filter whose parameters are automatically tuned using seismic data
alone. Application of our technique to single stations shows that signal
enhancement is best when reverberation is attributable to a single
layer. On glaciers where the reverberating sediment layer is sandwiched
between the lithosphere and an overlying ice layer, homomorphic analysis
is preferable in detecting the signature of reverberation. We expect
that our technique will see wide application for high-resolution body
wave imaging across a wide variety of conditions.