Fig. 1: Simplified Iliamna terrace data and interpretations
We estimated the height of elevated beaches along the Lake Iliamna coast by surveying across beach ridges and erosional scarps until we surpassed the highest scarp. Our observations appear to show that there is a step in the height of this beach, likely caused by an active fault. For comparison, hypothetical no-deformation and tilting cases are plotted. Tilting can explain much of the data, but in many places the crucial scarp must have been coincidentally undercut by a later scarp. Also, two scarps in the middle of our transects cannot be explained by tilting. The data here is simplified for clarity, and more detailed data and interpretation figures are provided in on our technical Lake Iliamna terraces section. All the data is shown on Map 5, and an additional figure shows details of the two transects bracketing the apparent fault.