B. Cagnoli et Tj. Ulrych, Singular value decomposition and wavy reflections in ground-penetrating radar images of base surge deposits, J APP GEOPH, 48(3), 2001, pp. 175-182
High-pass eigenimages of ground-penetrating radar (GPR) profiles were compu
ted in order to quantify the amount of wavy reflections. These wavy reflect
ions are caused by the presence of subsurface trains of climbing dune-forms
in the base surge deposits of the Ubehebe hydrovolcanic field (Death Valle
y National Park, California). The profiles were collected along a flow dire
ction radial to the Ubehebe Crater to study the lateral facies variation of
the pyroclastic deposits. The reflections become increasingly less wavy mo
ving away from the crater because the number and size of the climbing dune-
forms decrease downflow. The high-pass eigenimages act as a filter discardi
ng the highly correlated parts of the traces (i.e. those forming the flat r
eflections) and leaving the portions of the profiles with the wavy reflecti
ons. For this reason, the energy of the eigenimages appears to be an index
of the waviness of the reflections. This index is relatively fast to comput
e and quantifies the decrease of the number and size of the climbing dune-f
orms in the deposits. (C) 2001 Elsevier Science B.V. All rights reserved.