What geological activities may cause tidal gauges to move vertically?

The movement of tidal gauges vertically is significantly influenced by geological activities, primarily through processes such as post-glacial rebound and tectonic uplift.

Post-glacial rebound refers to the rise of land that has been depressed by the weight of ice sheets during the last Ice Age. As the ice melts and the weight is removed, the land gradually rises back to its original elevation, which can affect the vertical position of tidal gauges located on that land. This process is ongoing and can vary regionally based on the amount of ice cover that was present and the geological makeup of the area.

Tectonic uplift occurs due to the movements of tectonic plates. When these plates collide, one may be forced upward, leading to a gradual rise in land elevation in certain regions. This uplift can also cause shifts in the elevation of tidal gauges, impacting the measurement of sea level changes over time.

These geological processes are fundamental to understanding the mechanisms that can alter the positions of tidal gauges and thus affect local and global sea level monitoring efforts.