2025 Volume 81 Issue 17 Article ID: 25-17016
One type of Natech (natural hazard-triggered technological accident) involves the secondary impact caused by chemical substances that leak from industrial facilities into rivers during earthquakes and subsequently spread due to tsunami run-up.
In this study, based on previous research, a two-dimensional/three-dimensional hybrid numerical simulation was conducted to account for the effects of density-driven flow and tsunami propagation. The distribution of leaked chemicals was visualized in both horizontal and vertical directions, and the influence of differences in chemical density and release location on diffusion behavior was evaluated.
The results revealed that higher-density chemicals are more strongly affected by density currents, tend to diffuse into lower layers, and are more influenced by riverbed topography. In addition, regardless of the release location, chemicals were found to accumulate near the upper right bank. Furthermore, a hazard map was developed for the post-tsunami scenario, providing valuable insights for improving the impact assessment of water intake facilities.
