The determination of fault movement history from the interaction of local drainage with volcanic episodes

Abstract

The Kula volcanic province lies in an area of active normal faulting in western Turkey. In this study, we show that the interaction of the basalts with the local drainage, and in particular the Gediz river, can be used to determine the history of fault movements downstream. The lava flows have been studied previously, and some of them dated. We use these results and combine them with new field observations of lavas that flowed into the river valley to measure the rate of down-cutting of the river and hence the rate of uplift of the footwall block due to movement of the graben-bounding fault. We show that there has been, in general, an acceleration of fault movement with time during the last 2 Ma. This increased activity of the graben-bounding fault is matched by an intensification of volcanic activity. An inferred four-fold increase in fault movement rate over the last 0.2 Ma has been matched by a similar increase in volume of volcanic activity.