Geology Lesson - How Are Waterfalls Formed
Waterfalls are formed as water flows over different layers of rock which each erode at different rates.
Materials in the image are not found in Hawaii
As the water flows over the years, the soft rock is cut into by the water ultimately making the watercourse steeper beyond the hard rock layer, initially forming a step in the riverbed. As the rock erodes away, the watercourse becomes steeper and the water's speed increases thanks to gravity increasing the rate of erosion. Typically cascades and rapids are at this 1st stage of waterfall development.
With the water continuing to cut into the softer rock, the pool gets deeper, increasing the relative height of the waterfall, and the soft rock directly beneath the waterfall gets undercut. At this 2nd stage of waterfall development the water will not touch the cliff as the hard rock layer at the top is overhanging the softer eroded layers below.
As this process continues over time, eventually the hard rock layer will be undercut so much it will collapse into the base of the waterfall. Once the hard rock layer has eroded and collapsed completely, the watercourse will eventually revert back to a stream or a rapid.
Please send the answers to me and do not post them to your log.
- 1. What are the 5 water falls and their heights listed at the posted coordinates?
- 2. Using the cache page and by observing the waterfall, what stage of it's life would you say 'Akaka Falls are at?
- 3. What is the soft rock listed at the alternate coordinates that eroded away quickly?
- 4. What is the hard rock listed at the alternate coordinates that remained to create the waterfall?
- 5. Optional: A picture of your caching group at the observation point to 'Akaka Falls.
World of Waterfalls
Congratulations to KFinders on the FTF!