Submarine terraces off the coast of Dokdo reveal how volcanic island topography responds to sustained geological subsidence and fluctuating sea levels over hundreds of thousands of years.
The findings map how Dokdo’s topography changed across a 600,000-year timeline despite roughly 35 distinct sea-level standstill periods. The research team published their findings in the international earth science journal Geophysical Research Letters.
Numerical models simulate terrain evolution at Dokdo
By combining these observational datasets with a custom numerical model capable of calculating wave-induced erosion and geomorphic change, the team simulated long-term terrain evolution in a sinking marine environment.
Dokdo represents an isolated volcanic island where volcanic activity ceased between one million and 500,000 years ago. Subsidence measurements indicate the island sinks gradually at a rate of 0.13 meters per thousand years. This slow-sinking baseline provides an ideal natural laboratory for studying how marine terraces form and persist when tectonic subsidence outpaces or coincides with glacio-eustatic sea-level fluctuations.
Contrasting Preservation Patterns in Subsiding Volcanic Islands
Traditional marine terrace research focuses heavily on uplifting coastal regions, where higher elevation terraces generally correspond to older formation dates during specific highstand periods.
Although historical data records approximately 35 sea-level stillstands over the past 600,000 years around Dokdo, current underwater surveys identify only six distinct terrace levels preserved along the submarine slopes. The numerical modeling explains that ongoing subsidence subjects earlier marine platforms to repeated wave action and submergence, erasing most historical shorelines while leaving behind a durable subset of wave-cut platforms.
Frequently Asked Questions About Dokdo Submarine Terraces
How fast is Dokdo sinking into the sea?
Geological analysis shows that Dokdo sinks at an average rate of 0.13 meters every 1,000 years as an isolated volcanic island following the end of its active volcanic phase.
How many marine terraces currently survive underwater near Dokdo?
Out of approximately 35 sea-level standstill periods occurring over the past 600,000 years, exactly six distinct terrace structures remain clearly preserved on the submarine floor.