EPSC 181 Lecture Notes - Lecture 9: Sitka, Alaska, Tectonic Uplift, Post-Glacial Rebound
6 Nov 2018
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Document Summary
Tectonic activity can result in subsidence or uplift of land with respect to sea level, translating into relative sea-level rise or fall. Mantle is squishy and the plates slide along it. If a mountain were added to the crust, it would sink down. If a mountain were removed, it would rise back up. Most places have rising sea levels that can reflect that globally. Galveston, texas, sea levels are rising much faster because the land is also sinking. Sitka, alaska, sea levels are decreasing because the land is rising. Coral reefs require shallow water (sunlight to photosynthesis) Both erosion and isostatic adjustment lower the volcano. We"ve built stuff based on where we think the shoreline is, but the shoreline is changing. Cities built on coastal sands and muds often sink (weight of buildings and groundwater extraction) The water that floods the city is half salty half fresh so it can"t be used for drinking.
