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

The Kula volcanic province lies in an area of active normal faulting in wes tern Turkey. Ttl this study, we show that the interaction of the basalts wi th the local drainage, and in particular the Gediz river, can be used to de termine the history of fault movements downstream. The lava flows have been studied previously and some of them dated. We use these results and combin e them with new field observations of lavas that Bowed into the river valle y to measure the rate of down-cutting of the river and hence the rate of up lift 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 wi th time during the last 2 Ma. This increased activity of the graben-boundin g 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 mat ched by a similar increase in volume of volcanic activity.