the 22nd Pacific−Asian Marginal Seas meeting (PAMS)

For paleo-extreme event reconstruction, considerable interest has focused on identifying geochemical signatures capable of distinguishing sediment transport events triggered by earthquakes and storms. However, validation of such proxies using deposits that can be unequivocally linked to specific triggering events remains limited. In 2024, a sediment trap experiment was conducted offshore of Hualien, a region frequently impacted by both earthquakes and typhoons. Event deposits associated with an M6.3 earthquake and a flood induced by Super Typhoon Kong-Rey were successfully captured. Dual carbon isotopic (¹³C and ¹⁴C) and molecular analyses of organic matter reveal that the earthquake enhanced the remobilization of pre-aged organic carbon, whereas the typhoon facilitated the export of fresh organic carbon enriched in lignin to the deep sea. These results underscore the important role of typhoons in carbon sequestration and provide a modern calibration of carbon fingerprints that can be used to distinguish event deposits generated by different triggering mechanisms.

Density flow,organic carbon burial,Sediment transport,Typhoon,Earthquake