(a) Likelihood evolution. Black dots show the likelihood of MCMC samples by 20 non-tempered chains. The underlying grey dots show the results of independent inversion without parallel tempering for which 100 non-tempered chains were employed. The yellow-shaded area highlights iterations after the burn-in period. (b) Histograms of the likelihood sampled by non-tempered MCMC chains at the 6 000 000th iteration. The black and grey histograms show the results with and without the tempering scheme, respectively.