Discovery Learning 1
Was Dokdo always this small?
Underwater Topography near Ulleungdo and DokdoUlleung Plateau, Ulleungdo, Mt. An Yong-bok, Dokdo, Mt. Simheungtaek, Mt. Isabu
Submerged mountains over 1,000 meters in height are called underwater mountains.
Dokdo was formed approximately 4.6 million years ago when an underwater volcano erupted. Jejudo, Ulleungdo, and Dokdo are a few of the Korean islands that formed from underwater volcano eruptions. Dokdo was the first to form and is the smallest of the three. It is also the furthest from the mainland. Ulleungdo was formed about 2.5 million years after Dokdo, and Jejudo appeared around 3.4 million years after Dokdo.
When viewed underwater, Ulleungdo and Dokdo are part of a series of underwater mountain ranges and valleys. It is likely that these all formed from similar volcanic activity. The underwater mountain ranges to the east of Ulleungdo and Dokdo are older.
Seodo and Dongdo’s formationSeodo and Dongdo’s shapes were formed by wind and water erosion!
The islands were shaped by underwater volcanic activity!
※ ※ The height of the mountain has been exaggerated and enhanced by four times in relation to the width of the base.
Since Dokdo and Ulleungdo were created with similar volcanic activity, their geological composition is very similar. Japan’s Oki Islands have a completely different geological content than those found in Dokdo and Ulleungdo. In geographical terms, Ulleungdo and Dokdo are of the same formation, while Oki Islands are completely unrelated.
Dokdo features an underwater mountain approximately 2,200 meters in height, meaning that it is higher than Jejudo’s Mt. Halla. Dokdo was originally a volcanic mountain in which Seodo and Dongdo were unified. Over hundreds of thousands of years, wind and waves have slowly eroded away its original shape and today we have Seodo and Dongdo.
- Discovery Learning 1
1. Explain how Ulleungdo and Dokdo are geologically similar.
2. Describe how volcanic activity and erosion have shaped Dokdo.