Sea caves facts for kids

A Sea cave in Oregon

A sea cave is a hollow space or chamber found in a coastal cliff. These amazing natural features are carved out by the powerful force of crashing waves. Other cool shapes like "sea arches" and "sea stacks" are also created from these same rocky cliffs. The ocean's waves are constantly at work, both wearing away the land and depositing new materials. The process where the sea wears away the land is called marine erosion.

What Are Sea Caves?

Sea caves are basically tunnels or rooms that form in the sides of cliffs along the coast. They are created over many, many years by the ocean. Imagine waves constantly hitting the same spot on a rock. Over time, this steady pounding can wear away the rock, forming a cave.

How Sea Caves Form

Sea caves form mainly through a process called erosion. Here's how it works:

• Wave Power: Waves carry a lot of energy. When they crash against a cliff, they can break off small pieces of rock.
• Hydraulic Action: As waves hit the cliff, air gets trapped in cracks and crevices. When the wave pulls back, this trapped air expands quickly, putting pressure on the rock and making cracks bigger.
• Abrasion: Waves also carry sand, pebbles, and even larger rocks. These materials act like sandpaper, grinding against the cliff face and wearing it down.
• Chemical Weathering: Sometimes, the water itself can dissolve certain types of rock, like limestone, which also helps to form caves.

Over time, these processes work together to carve out the rock, creating the hollow space of a sea cave.

Sea Arches and Sea Stacks

Sea caves are often part of a bigger story of coastal erosion that also creates other interesting landforms:

• Sea Arches: If a sea cave forms on both sides of a narrow headland (a piece of land sticking out into the sea), the waves might eventually meet in the middle. This can create a hole right through the headland, forming a natural arch.
• Sea Stacks: Over even more time, the top of a sea arch might collapse. When this happens, it leaves behind isolated pillars of rock standing in the sea. These are called sea stacks. They are like lonely towers of rock that once were part of the coastline.

Where to Find Sea Caves

Sea caves can be found all over the world, especially in areas with rocky coastlines. Some famous examples include:

• The Oregon Coast in the United States, known for its many sea caves and arches.
• The Na Pali Coast in Hawaii, which has stunning sea caves accessible by boat.
• The Blue Grotto in Capri, Italy, famous for its glowing blue water inside the cave.
• Many islands and coastlines with basalt rock, like Akun Island in Alaska, also feature impressive sea caves.

These caves are often explored by kayakers, divers, and adventurers, offering a unique way to experience the power and beauty of the ocean.

Images for kids

• 

  Sea cave formation along a fault on Santa Cruz Island, California, United States

• 

  Sea cave collapse

• 

  Akun Island basalt sea cave

• 

  Exploring a sea cave