Choice of regularization in adjoint tomography based on two-dimensional synthetic tests

0448532 - GFÚ 2016 RIV GB eng J - Journal Article
Valentová, L. - Gallovič, F. - Růžek, Bohuslav - de la Puente, J. - Moczo, P.
Choice of regularization in adjoint tomography based on two-dimensional synthetic tests.
Geophysical Journal International. Roč. 202, č. 2 (2015), s. 787-799. ISSN 0956-540X. E-ISSN 1365-246X
Institutional support: RVO:67985530
Keywords : numerical approximations and analysis * seismic tomography * Europe
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 2.484, year: 2015

We present synthetic tests of 2-D adjoint tomography of surface wave traveltimes obtained by the ambient noise cross-correlation analysis across the Czech Republic. The data coverage may be considered perfect for tomography due to the density of the station distribution. Nevertheless, artefacts in the inferred velocity models arising from the data noise may be still observed when weak regularization (Gaussian smoothing of the misfit gradient) or too many iterations are considered. To examine the effect of the regularization and iteration number on the performance of the tomography in more detail we performed extensive synthetic tests. Instead of the typically used (although criticized) checkerboard test, we propose to carry out the tests with two different target models-simple smooth and complex realistic models. The first test reveals the sensitivity of the result on the data noise, while the second helps to analyse the resolving power of the data set. For various noise and Gaussian smoothing levels, we analysed the convergence towards (or divergence from) the target model with increasing number of iterations.
Permanent Link: http://hdl.handle.net/11104/0250207