Upper shoreface

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Cross-bedded upper shoreface sandstones CB UpShoreface.jpg
Cross-bedded upper shoreface sandstones
Wave base diagram. Wavebase.jpg
Wave base diagram.

Upper Shoreface refers to the portion of the seafloor that is shallow enough to be agitated by everyday wave action, the wave base. [1]

Wave base The maximum depth at which a water waves passage causes significant water motion

The wave base, in physical oceanography, is the maximum depth at which a water wave's passage causes significant water motion. For water depths deeper than the wave base, bottom sediments and the seafloor are no longer stirred by the wave motion above.


Below that is the lower shoreface.


The continuous agitation of the sea floor in the upper shoreface environment results in sediments that are winnowed of the smallest grains, leaving only those grains heavy enough that the water cannot keep them suspended. [1]

Depth of influence

Seawater is moved in a vertical circular motion when a wave passes. The radius of the circle of motion for any given water molecule decreases with depth.

Seawater Water from a sea or ocean

Seawater, or salt water, is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5%. This means that every kilogram of seawater has approximately 35 grams (1.2 oz) of dissolved salts. Average density at the surface is 1.025 kg/L. Seawater is denser than both fresh water and pure water because the dissolved salts increase the mass by a larger proportion than the volume. The freezing point of seawater decreases as salt concentration increases. At typical salinity, it freezes at about −2 °C (28 °F). The coldest seawater ever recorded was in 2010, in a stream under an Antarctic glacier, and measured −2.6 °C (27.3 °F). Seawater pH is typically limited to a range between 7.5 and 8.4. However, there is no universally accepted reference pH-scale for seawater and the difference between measurements based on different reference scales may be up to 0.14 units.

Radius segment in a circle or sphere (from its center to its perimeter or surface) and its length

In classical geometry, a radius of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the Latin radius, meaning ray but also the spoke of a chariot wheel. The plural of radius can be either radii or the conventional English plural radiuses. The typical abbreviation and mathematical variable name for radius is r. By extension, the diameter d is defined as twice the radius:

The maximum depth of influence of a water wave is half the wavelength. Below that depth the water remains stationary as the wave passes.

Wavelength spatial period of the wave—the distance over which the waves shape repeats, and thus the inverse of the spatial frequency

In physics, the wavelength is the spatial period of a periodic wave—the distance over which the wave's shape repeats. It is the distance between consecutive corresponding points of the same phase on the wave, such as two adjacent crests, troughs, or zero crossings, and is a characteristic of both traveling waves and standing waves, as well as other spatial wave patterns. The inverse of the wavelength is called the spatial frequency. Wavelength is commonly designated by the Greek letter lambda (λ). The term wavelength is also sometimes applied to modulated waves, and to the sinusoidal envelopes of modulated waves or waves formed by interference of several sinusoids.

For instance, in a pool of water 1 foot (0.30 m) deep, a wave with a wavelength of 1 foot (0.30 m) would not be able to cause water movement on the bottom. However, a wave with a 2 feet (0.61 m) wavelength would be moving the water (barely) at the bottom.

See also

In fluid dynamics, dispersion of water waves generally refers to frequency dispersion, which means that waves of different wavelengths travel at different phase speeds. Water waves, in this context, are waves propagating on the water surface, with gravity and surface tension as the restoring forces. As a result, water with a free surface is generally considered to be a dispersive medium.

Lower shoreface The portion of the seafloor, and the sedimentary depositional environment, that lies below the everyday wave base

Lower Shoreface refers to the portion of the seafloor, and the sedimentary depositional environment, that lies below the everyday wave base.

When waves travel into areas of shallow water, they begin to be affected by the ocean bottom. The free orbital motion of the water is disrupted, and water particles in orbital motion no longer return to their original position. As the water becomes shallower, the swell becomes higher and steeper, ultimately assuming the familiar sharp-crested wave shape. After the wave breaks, it becomes a wave of translation and erosion of the ocean bottom intensifies.

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Ripple tank

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Barrier island A coastal dune landform that forms by wave and tidal action parallel to the mainland coast

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Physical oceanography The study of physical conditions and physical processes within the ocean

Physical oceanography is the study of physical conditions and physical processes within the ocean, especially the motions and physical properties of ocean waters.

Capillary wave Wave on the surface of a fluid, dominated by surface tension

A capillary wave is a wave traveling along the phase boundary of a fluid, whose dynamics and phase velocity are dominated by the effects of surface tension.

Wind wave Surface waves generated by wind on open water

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

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Internal wave Gravity waves that oscillate within a fluid medium with density variation with depth, rather than on the surface

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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.

Depositional environment The combination of physical, chemical and biological processes associated with the deposition of a particular type of sediment

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Underwater acoustics The study of the propagation of sound in water and the interaction of sound waves with the water and its boundaries

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Wave-formed ripple

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In fluid dynamics, Airy wave theory gives a linearised description of the propagation of gravity waves on the surface of a homogeneous fluid layer. The theory assumes that the fluid layer has a uniform mean depth, and that the fluid flow is inviscid, incompressible and irrotational. This theory was first published, in correct form, by George Biddell Airy in the 19th century.

In fluid dynamics, wave–current interaction is the interaction between surface gravity waves and a mean flow. The interaction implies an exchange of energy, so after the start of the interaction both the waves and the mean flow are affected.

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  1. 1 2 R. G. Dean and R. A. Dalrymple (1991). Water wave mechanics for engineers and scientists. Advanced Series on Ocean Engineering. 2. World Scientific, Singapore. ISBN   978-981-02-0420-4.