Open AccessTeleseismic waveform modelling with a one‐way wave equation
Author(s) -
Audet Pascal,
Bostock Michael G.,
Mercier JeanPhilippe
Publication year - 2007
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1111/j.1365-246x.2007.03586.x
Subject(s) - lithosphere , geology , subduction , terrane , mantle (geology) , seismic anisotropy , seismometer , geophysics , anisotropy , waveform , seismology , physics , tectonics , optics , quantum mechanics , voltage
SUMMARY It is now widely accepted that elastic properties of the continental lithosphere and the underlying sublithospheric mantle are both anisotropic and laterally heterogeneous at a range of scales. To fully exploit modern three‐component broad‐band array data sets requires the use of comprehensive modelling tools. In this work, we investigate the use of a wide‐angle, one‐way wave equation to model variations in teleseismic 3‐D waveforms due to 2‐D elastic heterogeneity and anisotropy. The one‐way operators are derived based on a high‐frequency approximation of the square‐root operator and include the effects of wave propagation as well as multiple scattering. Computational cost is reduced through a number of physically motivated approximations. We present synthetic results from simple 1‐D (layer over a half‐space) and 2‐D (subduction zone) models that are compared with reference solutions. The algorithm is then used to model data from an array of broad‐band seismograph stations deployed in northwestern Canada as part of the IRIS‐PASSCAL/LITHOPROBE CANOE experiment. In this region radial‐component receiver functions show a clear continental Moho and the presence of crustal material dipping into the mantle at the suture of two Palaeo‐Proterozoic terranes. The geometry of the suture is better defined on the transverse component where subduction is associated with a ∼10 km thick layer exhibiting strong elastic anisotropy. The modelling reproduces the main features of the receiver functions, including the effects of anisotropy, heterogeneity and finite‐frequency scattering.