Wave pounding

Last updated

Wave pounding is the 'sledge hammer' effect of tonnes of water crashing against cliffs. It shakes and weakens the rocks leaving them open to attack from hydraulic action and abrasion. Eroded material gets carried away by the wave. Wave pounding is particularly fierce in a storm, where the waves are exceptionally large, and have a lot of energy. It is an important engineering consideration in the construction of structures such as seawalls and dams.

Water chemical compound

Water is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.

Hydraulic action

Hydraulic action is the erosion that occurs when the motion of water against a rock surface produces mechanical weathering. Most generally, it is the ability of moving water to dislodge and transport rock particles. Within this rubric are a number of specific erosional processes, including abrasion, attrition, corrasion, saltation, and scouring (downcutting). Hydraulic action is distinguished from other types of water facilitated erosion, such as static erosion where water leaches salts and floats off organic material from unconsolidated sediments, and from chemical erosion more often called chemical weathering. It is a mechanical process, in which the moving water current flows against the banks and bed of a river, thereby removing rock particles.I am going to fail my geography test so if you want a free mcflurry or something ill be working in mcdonalds so hit me up.

Erosion Processes which remove soil and rock from one place on the Earths crust, then transport it to another location where it is deposited

In earth science, erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, animals, and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolic) erosion, zoogenic erosion, and anthropogenic erosion. The particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion; this contrasts with chemical erosion, where soil or rock material is removed from an area by its dissolving into a solvent, followed by the flow away of that solution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres.

Wave pounding is a force of erosion along coast lines. The effects of wave pounding are influenced by wave shape, ocean chemistry, rock type, and morphology of the coastal landscape. There are three different types of waves to consider in this process: spilling, plunging, and surging waves. Spilling waves have the least amount of energy associated with them due to their shallow ocean floor. Plunging and surging waves contain the energy associated with wave pounding. Plunging and surging waves occur on moderate to steep angled beach plains.

Wave power Transport of energy by wind waves, and the capture of that energy to do useful work

Wave power is the capture of energy of wind waves to do useful work – for example, electricity generation, water desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC).

Along with energy, the water chemistry will also affect the rock exposed to the erosion. Salt, calcium, and acid levels in the ocean have adverse effects on specific rock types. The chemical weathering due to wave processes is part of why wave pounding is so damaging. Wave pounding is not primarily caused by tectonic margins. Wave pounding will occur any place around the world as long as the angle of the beach plain is steep enough to generate the plunging and surging waves. The action of wave pounding is the kinetic energy delivered by waves fracturing or removing rock and or sand from land sea margins. Any solid material not fully removed by this action will be hydraulically fractured as well. The surging water fills the existing cracks and physically wedges the rock apart. One specific rock is particularly susceptible to the hydraulic action.

Chert rock, or any other rock which has fractured and has had siliceous material fill in the cracks, seems to be very weak to wave action. The water can get into the bubbles and voids in the quartz fracture lines. Some beaches in northern California have broken cliff side with these same fracture patterns on the break line. Some shorelines with wave pounding have large sand deposits and loosely consolidated sand cliffs. Waves in these areas can be extra damaging due to the suspended sand material in the water. These sand cliff faces do not fracture in the same way that solid rock will.

Chert A hard, fine-grained sedimentary rock composed of crystals of quartz (silica) that are very small

Chert is a hard, fine-grained sedimentary rock composed of crystals of quartz (silica) that are very small (microcrystalline or cryptocrystalline). Quartz (silica) is the mineral form of silicon dioxide (SiO2). Chert is often of biological origin (organic) but may also occur inorganically as a chemical precipitate or a diagenetic replacement (e.g., petrified wood). Geologists use chert as a generic name for any type of microcrystalline or cryptocrystalline quartz.

Examples on the northern California coast line suggest that the water erodes the weakest veins of sand on the cliff face. This effectively carves out notches and weak points of the cliff leaving a large scale of sandstone ready to fall. A sandy cliff with wave pounding action present will appear as a large sand cliff with deep grooves carved laterally and slumped scales of sand mounding on the bottom edge of the cliff. Wave pounding can be a seasonal event or even a daily event depending on the beach. Specific beaches around the world have seasonal changes in the beach angle due to long shore sand drift patterns. These phenomena will affect the strength that a wave will hit the cliff face.

The rise and fall of tides also can mean the difference between a wave spilling onto the beach surface rather than into the cliff face. Wave pounding will affect most jetties and man made outcrops as well. The title of the wave will be different due to the depth of the water at the specific location. The waves do possess the power to damage or move stone on jetties. The steep edges of the jetties allow the waves to crash onto the rock.

Related Research Articles

Coast Area where land meets the sea or ocean

The coast, also known as the coastline or seashore, is the area where land meets the sea or ocean, or a line that forms the boundary between the land and the ocean or a lake. A precise line that can be called a coastline cannot be determined due to the coastline paradox.

Beach Area of loose particles at the edge of the sea or other body of water

A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles. The particles can also be biological in origin, such as mollusc shells or coralline algae.

Lagoon A shallow body of water separated from a larger body of water by barrier islands or reefs

A lagoon is a shallow body of water separated from a larger body of water by barrier islands or reefs. Lagoons are commonly divided into coastal lagoons and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world.

Coastal erosion The loss or displacement of land along the coastline due to the action of waves, currents, tides. wind-driven water, waterborne ice, or other impacts of storms

There are two common definitions of coastal erosion. It is often defined as the loss or displacement of land along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. In this case, landward retreat of the shoreline, measured to a given spatial datum, is described over a temporal scale of tides, seasons, and other short-term cyclic processes. Alternatively, it is defined as the process of long-term removal of sediment and rocks at the coastline, leading again to loss of land and retreat of the coastline landward. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural.

Both headland and bay are two coastal features that are related and often found on the same coastline. A bay is a body of water—usually seawater and sometimes fresh water— mostly surrounded by land, whereas a headland is surrounded by water on three sides. Headlands are characterized by breaking waves, rocky shores, intense erosion and steep sea cliffs. Bays generally have less wave activity and typically have sandy beaches. Headlands and bays form on discordant coastlines, where the land consists of bands of rock of alternating resistance that run perpendicular to the coast.

Longshore drift Sediment moved by the longshore current

Longshore drift from longshore current is a geological process that consists of the transportation of sediments along a coast parallel to the shoreline, which is dependent on oblique incoming wind direction. Oblique incoming wind squeezes water along the coast, and so generates a water current which moves parallel to the coast. Longshore drift is simply the sediment moved by the longshore current. This current and sediment movement occur within the surf zone.

Wave-cut platform The narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or sea that was created by erosion

A wave-cut platform, shore platform, coastal bench, or wave-cut cliff is the narrow flat area often found at the base of a sea cliff or along the shoreline of a lake, bay, or sea that was created by erosion. Wave-cut platforms are often most obvious at low tide when they become visible as huge areas of flat rock. Sometimes the landward side of the platform is covered by sand, forming the beach, and then the platform can only be identified at low tides or when storms move the sand.

Coastal geography The study of the region between the ocean and the land

Coastal geography is the study of the constantly changing region between the ocean and the land, incorporating both the physical geography and the human geography of the coast. It includes understanding coastal weathering processes, particularly wave action, sediment movement and weather, and the ways in which humans interact with the coast

Coastal management

Coastal management is defence against flooding and erosion, and techniques that stop erosion to claim lands.

Swash A turbulent layer of water that washes up on the beach after an incoming wave has broken

Swash, or forewash in geography, is a turbulent layer of water that washes up on the beach after an incoming wave has broken. The swash action can move beach materials up and down the beach, which results in the cross-shore sediment exchange. The time-scale of swash motion varies from seconds to minutes depending on the type of beach. Greater swash generally occurs on flatter beaches. The swash motion plays the primary role in the formation of morphological features and their changes in the swash zone. The swash action also plays an important role as one of the instantaneous processes in wider coastal morphodynamics.

Surf forecasting is the process of using offshore swell data to predict onshore wave conditions. It is used by millions of people across the world, including professionals who put their forecasts online, meteorologists who work for news crews, and surfers all over the world. It is impossible to make an exact prediction of the surf, but by knowing a few factors a good prediction can be made. One needs to have an understanding of how waves are formed, a basic knowledge of bathymetry, and information about the surf spot being forecasted to accurately forecast the surf.

Breaking wave A wave that becomes unstable as a consequence of excessive steepness

In fluid dynamics, a breaking wave is a wave whose amplitude reaches a critical level at which some process can suddenly start to occur that causes large amounts of wave energy to be transformed into turbulent kinetic energy. At this point, simple physical models that describe wave dynamics often become invalid, particularly those that assume linear behaviour.

The shoreline is where the land meets the sea and it is continually changing. Over the long term, the water is eroding the land. Beaches represent a special case, in that they exist where sand accumulated from the same processes that strip away rocky and sedimentary material. That is, they can grow as well as erode. River deltas are another exception, in that silt that erodes up river can accrete at the river's outlet and extend ocean shorelines. Catastrophic events such as tsunamis, hurricanes and storm surges accelerate beach erosion, potentially carrying away the entire sand load. Human activities can be as catastrophic as hurricanes, albeit usually over a longer time interval.

Sand dune stabilization

Sand dunes are common features of shoreline and desert environments. Dunes provide habitat for highly specialized plants and animals, including rare and endangered species. They can protect beaches from erosion and recruit sand to eroded beaches. Dunes are threatened by human activity, both intentional and unintentional. Countries such as the United States, Australia, Canada, New Zealand, the United Kingdom, and Netherlands, operate significant dune protection programs.

Surf break A permanent obstruction on the seabed which causes waves to break

A surf break is a permanent obstruction such as a coral reef, rock, shoal, or headland that causes a wave to break, forming a barreling wave or other wave that can be surfed, before it eventually collapses. The topography of the seabed determines the shape of the wave and type of break. Since shoals can change size and location, affecting the break, it takes commitment and skill to find good breaks. Some surf breaks are quite dangerous, since the surfer can collide with a reef or rocks below the water.

Canterbury Bight is a 135 kilometres (84 mi) stretch of coastline between Dashing Rocks and the southern side of Banks Peninsula on the eastern side of the South Island, New Zealand. The bight faces southeast, which exposes it to high-energy storm waves originating in the Pacific Ocean. The most frequent wave approach direction for the Canterbury Bight is from the southeast and the most dominant the south with wave heights of over 2m common. The bight is a large, gently curving bend of shoreline of primarily mixed sand and gravel (MSG) beaches. The MSG beaches are steep, highly reflective and composed of alluvial gravel deposits. The alluvial gravels are the outwash products of multiple glaciations that occurred in the Southern Alps during the Pleistocene. Large braided rivers transported this material to the edge of the current continental shelf, which, due to sea level rise is 50 km seaward of the coasts current position. The MSG beaches of the Canterbury Bight therefore occur where the alluvial fans of the Canterbury Plains rivers are exposed to high-energy ocean swells. The dominant rock ‘greywacke’ in the Southern Alps is consequently the primary constituent of the MSG beaches, which is partially indurated sandstone of the Torlesse Supergroup. River-mouth lagoons are a relatively common occurrence on the MSG beaches of the Canterbury Bight.

Cliffed coast A form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous

A cliffed coast, also called an abrasion coast, is a form of coast where the action of marine waves has formed steep cliffs that may or may not be precipitous. It contrasts with a flat or alluvial coast.

Coastal hazards

Coastal Hazards are physical phenomena that expose a coastal area to risk of property damage, loss of life and environmental degradation. Rapid-onset hazards last over periods of minutes to several days and examples include major cyclones accompanied by high winds, waves and surges or tsunamis created by submarine earthquakes and landslides. Slow-onset hazards develop incrementally over longer time periods and examples include erosion and gradual inundation.

References

International Standard Book Number Unique numeric book identifier

The International Standard Book Number (ISBN) is a numeric commercial book identifier which is intended to be unique. Publishers purchase ISBNs from an affiliate of the International ISBN Agency.