| Abstrak/Abstract |
Research on tsunami deposits generated by subaerial and subaqueous landslide-triggering mechanisms, such as the 2018 Anak Krakatau tsunami, remains comparatively scarce. Consequently, the characterization of these deposits is less comprehensive than that of earthquake-induced tsunamis. Few investigations have specifically targeted the characteristics of deposits resulting from this particular tsunami generation mechanism, and the geochemical characteristics of the 2018 Anak Krakatau tsunami deposit have yet to be systematically explored. Previous research has shown that organic geochemical patterns can serve as indicators for identifying paleotsunami deposits by comparing them to underlying pre-tsunami soil horizons. This study analyzes the organic geochemistry of sandy tsunami deposits from the 2018 Anak Krakatau event and compares them with samples from adjacent beach, dune, and pre-tsunami soil horizons. Using gas chromatography–mass spectrometry (GC–MS), we identified marked variations in organic composition and anthropogenic contamination across the sample types. Soil samples exhibited a more natural and stable chemical environment as they were primarily composed of terrestrial organic matter. Tsunami deposits, in contrast, showed a high concentration of synthetic pollutants, especially those derived from plastics and industries. Dune and beach samples reflected their respective coastal contexts, with the dune being influenced more by land pollution and the beach showing a dynamic assemblage of terrestrial and marine materials. This study not only improves our knowledge concerning deposits produced by the short-wavelengths tsunami but also establishes a preliminary and new criteria for identifying and reconstructing paleotsunamis on a worldwide scale. |
