9:35 AM - 9:50 AM
[HCG25-03] Uplift-induced drainage divide migration and channel reorganization : Laboratory model experiment
Keywords:fluvial morphology, drainage divide
A drainage divide is modified by external forcing, changing its position and elevation, which results in reorganization of the channel. Tilt uplift, i.e. uneven uplift rate,is a common factor as forcing, and a key for understanding of past and future landforms in tectonically complicated regions such as Japan.Its detailed dynamics, however, are not still well understood. Here, we consider divide migration and channel reorganization caused by tilt uplift, through topographic analysis of Sado Island, where tilt uplift occurrs, along with laboratory model experiment. In the tilt uplift, it is possible to distinguish between the seaward uplift side, where the uplift is dominant, and the landward uplift side, where the uplift is dominant, and it is thought to move toward the seaward uplift side. On the western side of Osado Island, the seaward uplift is considered to move the to the west, but the divide is located in the center from the south to the center, and to the east in the north. A comparison of the Gilbert metrics and χ across the, which is an index to estimate the movement of the, does not suggest the movement of the in the south to the center, while it suggests the movement to the west in the north. The geomorphic development of Osado will be discussed along with the results of the laboratory model.