Tortola - coastal erosion 🌊 EarthCache

As you enter Road Town Harbor, you will be able to observe the cliff face to your right.

What Is Erosion and How Does It Shape the Earths Surface
Erosion is the name for the processes that both break down rocks (weathering) and carry away the breakdown products (transportation). As a general rule, if rock is just broken down through mechanical or chemical means, then weathering has occurred. If that broken-down material gets moved at all by water, wind or ice, then erosion has occurred. 

 
Agents of Erosion
The agents of erosion are ice, water, waves, and wind. As with any natural process that takes place on the Earth;s surface, gravity plays a major role as well.

Water is perhaps the most important (or at least most visible) agent of erosion. Raindrops strike the surface of the Earth with enough force to break apart soil in a process known as splash erosion. Sheet erosion occurs as water collects on the surface and moves toward small streams and rivulets, removing a widespread, thin layer of soil along the way.

Gully and rill erosion occurs as runoff becomes concentrated enough to remove and transport larger amounts of soil. Streams, depending on their size and speed, can erode away banks and bedrock and transport large pieces of sediment. 

Glaciers erode through abrasion and plucking. Abrasion occurs as rocks and debris become embedded on the bottom and sides of a glacierAs the glacier moves, the rocks scour and scratch the surface of the Earth.

Plucking takes place when meltwater enters cracks in the rock beneath a glacier. The water refreezes and breaks off large pieces of rock, which are then transported by glacial movement. U-shaped valleys and moraines are visible reminders of the awesome erosive (and depositional) power of glaciers. 

Waves cause erosion by cutting away at the shore. This process creates remarkable landforms like wave-cut platforms, sea arches, sea stacks, and chimneys. Due to the constant battering of wave energy, these landforms are usually short lived. 

Wind affects the surface of the Earth through deflation and abrasion. Deflation refers to the removal and transport of fine-grained sediment from the winds turbulent flow. As the sediment is airborne, it may grind and wear away surfaces with which it comes in contact. Like with glacial erosion, this process is known as abrasion. Wind erosion is most common in flat, arid areas with loose, sandy soils. 

Human Impact on Erosion
Although erosion is a natural process, human activities like agriculture, construction, deforestation, and grazing can greatly increase its impact. Agriculture is particularly notorious.
Areas that are conventionally plowed experience upwards of 10 times more erosion than normal. Soil forms at about the same rate that it naturally erodes, meaning that humans are currently stripping away the soil at a very unsustainable rate. 

Coastal Erosion
Coastal erosion is the wearing away of land and the removal of beach or dune sediments by wave action, tidal currents, wave currents, drainage or high winds

Cliffs are very steep, even overhanging rock faces formed by erosion. They overlap with escarpments, which are large tectonic cliffs.

To log this cache you must first send your answers to questions below then you may log the cache: 

Q1: Would you say weathering or erosion has occurred at the cliff face? Please give your reason for your answer.

Q2: What conditions have occurred to cause this?

Q3: Starting below the green roof building and ending below the large group of all white buildings; How many large valleys have been formed? Which is tallest, deepest (going inland away from the shore), and/or widest?

Once you have obtained your answers enjoy your holiday or boat trip and submit answers when you return home.