Liu, HuafengDai, NanxunNiu, FenglinWu, Wei2014-03-282014-03-282014Liu, Huafeng, Dai, Nanxun, Niu, Fenglin, et al.. "An explicit time evolution method for acoustic wave propagation." <i>Geophysics,</i> 79, no. 3 (2014) Society of Exploration Geophysicists: T117-T124. http://dx.doi.org/10.1190/GEO2013-0073.1.https://hdl.handle.net/1911/75786Cost-effective waveform modeling is the key to practical reverse time migration (RTM) and full-waveform inversion (FWI) implementations. We evaluated an explicit time evolution (ETE) method to efficiently simulate wave propagation in acoustic media with high temporal accuracy. We started from the constant-density acoustic wave equation and obtained an analytical time-marching scheme in the wave number domain. We then formulated an ETE scheme in the time-space domain by introducing a cosine function approximation. Although the ETE operator appears to be similar to the second-order temporal finite-difference (FD) operator, the exact nature of the ETE formula ensures high accuracy in time. We further introduced a set of optimum stencils and coefficients by minimizing evolution errors in a least-squares sense. Our numerical tests indicated that ETE can achieve similar waveform accuracy as FD with four times larger time steps. Meanwhile, the compact ETE operator keeps the computation efficient. The efficiency and capability to handle complex velocity field make ETE an attractive engine in acoustic RTM and FWI.engArticle is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.Journal articlehttp://dx.doi.org/10.1190/GEO2013-0073.1