Abstract

We use the stratigraphy preserved in a washover fan to reconstruct the timing or emplacement and environmental conditions along the Matagorda Peninsula, Texas, during Hurricane Ike in 2008. Washover fan stratigraphy preserves a topset-foreset break (TFB) that rises 0.42 m in elevation as the fan built landward. We constrain overwash flow depths to 0.1–0.32 m through deposit sedimentology, and tie the rising trajectory of the TFB to rising storm surge water levels measured in the back-barrier bay (0.03 m h–1) as the hurricane approached the coast. This relation allows us to estimate that the fan took 0.52–0.90 days to build, and was finished building before the storm surge peaked. This is 15–25% of the 3.5 days of hurricane-induced storm surge near the site. We show how washover stratigraphy can be used to constrain the timing and amount of sediment redistribution on a coast associated with a hurricane; information that is necessary to test and/or calibrate existing numerical models that predict shoreline change during hurricanes.

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