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Phytosociology and succession on earthquake-uplifted coastal wetlands, Copper River Delta, Alaska
Phytosociology and succession on earthquakeuplifted coastal wetlands Copper River Delta Alaska Author:John F. Thilenius The delta formed by the Copper River stretches more than 75 kilometers along the south-central coastline of Alaska. It is the terminus of the outwash deposits from a large part of the most heavily glaciated region of North American, and all major rivers that flow into the delta carry extremely high levels of suspended sediments. Coastal wetlands... more » extend inland for as much as 20 kilometers. In 1964, an earthquake of Richter Scale 8.4 to 8.6 raised the entire delta from 1.8 to 3.4 meters above the previous mean sea level. Subtidal areas became intertidal, and intertidal areas supertidal. Marshland advanced seaward as much as 1.5 kilometers in the intertidal zone. Vegetation on many, but not all, newly supertidal levees began to change from herb to shrub. A change in frequency and duration of tidal inundation and water salinity has been thought to be the most obvious cause of this succession, but explanation is lacking.« less