Modeling the influence of Moho topography on receiver functions: A case study from the central Hellenic subduction zone

Pseudospectral 2D modeling of wave propagation provides a fresh look at receiver function data from the Hellenic subduction zone. It is shown that distinct Moho topography, which is suggested for this complex subduction environment from various geophysical data sets, can provide a conclusive explanation for previously observed “inverted” Moho phases in the forearc as well as for a complex sequence of apparently dipping conversions in the volcanic arc. Prominent effects of strongly dipping discontinuities include the change of sign in Ps phases refracted past the vertical and multiple P reflections that cannot be separated from Ps conversions during receiver function processing. Unambiguous identification of these phenomena can be hampered by poor azimuthal coverage of the data. Still, in regions where discontinuity topography can reasonably be expected, its effects should be considered when interpreting receiver functions, as results might be spurious otherwise.