Abstract Tsunami deposits offer valuable insights into the frequency, magnitude, and potential sources of historical and paleo‐tsunamis. However, previous studies have often overlooked the interaction between tsunamis and tides in sediment simulations, leaving a significant gap in evaluating tsunami‐induced inundation and sediment transport under tidal conditions. In this study, we investigated the impact of tides on tsunami‐induced sediment transport associated with potential earthquakes (∼Mw 9.0) from the Manila Subduction Zone (MSZ) in the South China Sea (SCS). Using the forward model COMCOT‐SED, simulations were conducted at a reported tsunami deposit site in the Qing'ao Embayment on Nan'ao Island. The experiments include scenarios incorporating time‐varying tidal effects at four different phases: high tide, low tide, flood tide, and ebb tide. Our findings reveal that tsunami‐tide interactions at different tidal phases significantly affect nearshore tsunami wave height, and nonlinear effects are most pronounced during the ebb tide scenario. The tidal level is the primary factor controlling onshore inundation and sediment distribution, while tidal current velocity and direction have a secondary influence. These interactions primarily influence sediment deposition and erosion processes by altering water depth and flow velocity, affecting volume flux and sediment transport rate during the tsunami flooding process. The results underscore the importance of considering the effects of tidal phases and sea level variation on tsunami inundation and deposition onshore when interpreting historical and paleo‐tsunamis with tsunami deposits. This study provides a quantitative understanding of tidal levels and current influences on tsunami hazard assessments and paleo‐tsunami research, offering critical insights for future studies.
Li et al. (Sun,) studied this question.