Array-based extraction of weak mantle reflections

Summary Seismic reflections from mantle discontinuities provide critical constraints on the structure and dynamics of Earth’s interior, but their extraction remains challenging due to low signal-to-noise ratios (SNR), interference from other seismic phases and uneven spatial distributions. In this study, we propose an array-based extraction strategy that integrates data reconstruction with subsequent denoising for enhancing the extraction of weak mantle reflections. This proposed strategy is independently implemented using the Curvelet-, F–K, and Radon transforms, and the performance of the three implementations is systematically evaluated. Compared with the time-space domain, coherent signals and noise are more easily separated in the transformed domain. We apply these methods to synthetic waveforms generated using a modified ak135 Earth model and test their effectiveness in retrieving reflections from the mantle transition zone (SS/PP precursors) and the D″ discontinuity (ScS/PcP precursors), including cases with random noise and missing traces. All three methods effectively isolate weak mantle reflections, with the Curvelet transform demonstrates the highest robustness and SNR improvement, particularly under conditions of sparse or noisy data. Field applications to data sampling the Central Pacific and Central America further confirm the methods’ ability to recover weak mantle reflections and expand the distance range of usable data. These results demonstrate the potential of array-based extraction strategy to advance deep Earth seismic imaging.