What is a Raised Beach?
Succinctly, this is a landform that was once a beach, but now lies considerably above sea level.
Raised beaches are also known as marine terraces, perched coastlines, and coastal terraces. This denotes flat, or gently sloping, nascent coastal land forms. Originating from the sea, raised beaches are platforms formed out of coastal erosion. While sea level remains the same, land that was once at sea level is eroded. This leaves the adjacent land further above sea level. Hence, a "raised" beach is formed.
How Are Raised Beaches Formed?
Factors that affect the formation of raised beaches are determined by tectonic activity and. climate conditions, Changes in climate have often affected the changes in sea level. Movement in the Earth's crust, particularly tectonic uplifts, can result in some raised beaches having defined terracing. These movements often vary between glacial and interglacial periods. Changes in sea level being a gradual transition can result in a raised beach not having overt signs of terracing. Glacial activity plays another factor in the formation of raised beaches. As glaciers melted, the land recovers from the weight of the ice. This process is known as isostatic rebound. The land begins to rise.
Depending on what the former range of the tides are, the platform of a raised beach varies. This can vary between one to five degrees. The profile will also vary between concave to linear. Raised beaches will also vary in width. They can be as wide as 1,000 metres (3,300 feet).
What is the Connection Between Raised Beaches and Earthquakes?
Because of how raised beaches are formed, they play a role in studying earthquakes. This is due to tectonic uplift. As tectonic uplift contributes to raised beaches, raised beached could also show patterns and the rates in which tectonic lift takes place. In measuring these rates, this can be used in estimating how much tectonic activity takes place in a region.
Raised beaches are found throughout the word. Countries such as, but not limited to, Chile, New Zealand, the United Kingdom (notably Scotland), Spain, Ireland, Canada, and the USA are all places they can be found.