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Introduction Coastal sediment supply is the delivery of mineral and organic material to the shore, principally by rivers (fluvial transport) and, to a lesser extent, by wind (aeolian transport). Fluvial sources provide the vast majority of sediment delivered to the ocean—on the order of 95%—while aeolian fluxes, though much smaller in volume, play a critical…

Coastal morphodynamics — Introduction Coastal morphodynamics examines how seabed geometry and sediment distributions evolve through interaction with fluid forcings — principally waves, tides and wind‑driven currents — to create and modify coastal landforms and sedimentary patterns. Hydrodynamic forcing adjusts essentially instantaneously to changes in bed form, whereas morphological adjustment requires sediment transport over finite timescales;…

Introduction Coastal management encompasses both engineered constructions and regulatory measures aimed at protecting shorelines from flooding and halting or reversing erosion, including projects that reclaim land from the sea. Iconic infrastructure such as the Netherlands’ Oosterscheldekering sea wall illustrates how large-scale engineering is used to shield low-lying territories from storm surge and inundation. Its importance…

Introduction to Coastal Geography Coastal geography examines the dynamic interface between ocean and land as an interdisciplinary field in which marine and terrestrial systems continuously interact and reshape one another. Its physical-geography remit encompasses coastal geomorphology (the origin, evolution and form of coastal landforms), climatology (the role of weather and climate in driving coastal processes…

Introduction Coastal erosion denotes the removal or displacement of land and sediment along shorelines by dynamic agents such as waves, currents, tides, wind‑driven water and ice, and episodic storm impacts. The consequence is a measurable, landward migration of the coastal boundary that can be observed on timescales from individual tides and seasons to longer cyclical…

Introduction Coastal engineering is the branch of civil engineering concerned with the planning, design, construction and maintenance of infrastructure located at or adjacent to shorelines, together with the management of coastal change itself. Practitioners analyse the principal hydrodynamic agents—waves, tides, storm surges and tsunamis—which govern sediment transport, impose structural loads and can produce rapid geomorphic…

Introduction — Coastal development hazards Coastal development hazards arise when human activity concentrates people, infrastructure and economic value in zones that are shaped by inherently dynamic coastal processes. By placing assets on the shoreline, development increases both the potential losses (vulnerability) and the practical probability that naturally occurring coastal phenomena will produce socially significant damage….

Introduction The Coastal and Estuarine Research Federation (CERF) is a U.S.-incorporated, private nonprofit established in 1971 to unite scientists and practitioners concerned with estuarine and coastal systems. Originating from an initiative by members of two regional societies—the Atlantic Estuarine Research Society and the New England Estuarine Research Society—CERF was created to fill a gap for…

Coal has been central to India’s energy system since the late 18th century; commercial coal mining began in 1774 and by FY 2024–25 India produced 1,047 million metric tons, making it the world’s second-largest producer and consumer after China. Domestic output supplies the majority of national demand, but India still imports roughly 15% of its…

India’s climate is exceptionally varied owing to its large latitudinal extent, complex topography and tectonic history; although the Tropic of Cancer bisects the country, much of India functions climatologically as tropical and the Köppen classification records multiple climatic subtypes across the territory. The uplift of the Himalayan chain beginning in the Early Eocene (≈52 Ma)…

Introduction Clastic sedimentary rocks are lithologies in which the dominant constituents are fragments—clasts—derived from pre-existing minerals and rocks by mechanical weathering. A clast denotes any detached piece of geological detritus, from sand-sized grains to larger rock fragments, and the adjective clastic applies both to the lithified rocks and to the unconsolidated particles involved in transport…

Introduction — Cinder cone A cinder cone, or scoria cone, is a small, steep-sided volcanic hill formed by the accumulation of loose pyroclastic fragments around a single vent. These cones result from relatively explosive, gas-rich eruptions that fragment ascending lava into ash, lapilli and scoria; the fragments cool in flight and fall back ballistically to…

Proposed in 1905 by Thomas C. Chamberlin and Forest R. Moulton as an alternative to the nineteenth‑century Laplacian nebular model, the Chamberlin–Moulton hypothesis sought to explain Solar System formation through a tidal interaction between the young Sun and a passing star. In the original formulation a close stellar encounter produced tidal bulges on the solar…

Introduction — Chaman Fault The Chaman Fault is a major active continental fault system exceeding 850 km in length that forms the primary structural boundary between the Eurasian and Indo‑Australian plates across Pakistan and Afghanistan. Its dominant movement is left‑lateral strike‑slip, with the western block shifting southward relative to the east, but the ongoing India–Eurasia…

Introduction The Cascadia subduction zone is a major convergent plate margin extending roughly 1,000 km along the Pacific coast of North America, lying about 100–200 km offshore from northern Vancouver Island, British Columbia, to northern California (representative coordinate ~45°N, 124°W). Along this margin the small oceanic plates—Explorer, Juan de Fuca, and Gorda, remnants of the…

Introduction The Caroline Plate is a minor oceanic tectonic plate in the eastern hemisphere that straddles the Equator and occupies the oceanic region immediately north of New Guinea. Its southern margin forms a plate‑consuming subduction zone with the Bird’s Head Plate and other small plates of the New Guinea region, producing a convergent boundary that…

The Caribbean Plate is a chiefly oceanic tectonic plate occupying approximately 3.2 million km2 (1.2 million mi2) of lithosphere beneath the Caribbean Sea and parts of Central America, lying north of the South American continental margin. As a major structural element of the region’s crust, it forms the foundation for an array of island arcs…

Introduction — Carbon dioxide in Earth’s atmosphere Continuous atmospheric CO2 measurements initiated at Mauna Loa Observatory in 1958, commonly presented as the Keeling Curve, record mole‑fraction in micromoles per mole (ppm) and show an uninterrupted rise from 1958 through 2023. On a molar basis CO2 reached about 427 ppm (0.0427%) by 2024, equivalent to roughly…

The Capricorn plate is a hypothesised minor tectonic entity beneath the Indian Ocean basin (southern–eastern hemispheres) whose formal recognition remains unresolved. It is interpreted as a relatively coherent block of oceanic lithosphere occupying the far western margin of the erstwhile Indo‑Australian plate; in this view Capricorn behaves in many respects like a discrete plate distinct…

Introduction — Burma Plate The Burma plate is a minor tectonic block in Southeast Asia, variably treated as an independent microplate or, for some tectonic syntheses, as part of the broader Eurasian plate. It carries the Andaman and Nicobar islands and northwestern Sumatra, which together form the Andaman–Nicobar–Sumatra island arc that separates the Andaman Sea…

Buoyancy (pronounced /ˈbɔɪənsi, ˈbuːjənsi/), or upthrust, is the net upward force that a fluid exerts on an immersed body or fluid parcel. It originates from the increase of hydrostatic pressure with depth: pressure acting over the submerged surface produces a larger resultant force on the bottom than on the top, yielding an upward resultant. Quantitatively,…

Introduction Consider a plane ruled into parallel strips of uniform width (t). A needle of length (l) is dropped at random; the event of interest is whether the needle intersects one of the parallel bounding lines (illustratively, one needle may straddle a line while another may lie entirely within a strip). Posed by Georges‑Louis Leclerc,…

Introduction A boundary layer is the thin region of fluid immediately adjacent to a solid surface in which the presence of the surface modifies the flow relative to the undisturbed free stream. Within this layer viscous interactions with the boundary alter momentum and, where relevant, scalar properties such as temperature or concentration; beyond the layer…

Introduction — Borders of the Oceans The World or Global Ocean is a single, continuous envelope of saline water surrounding Earth; for practical, navigational and political purposes it is conventionally divided on maps into principal oceanic areas. Most geographers and international bodies recognize five such divisions—Pacific, Atlantic, Indian, Southern (commonly termed Antarctic), and Arctic—whose relative…

Introduction A blowhole, sometimes called a marine geyser, is a coastal landform in which seawater is expelled through a surface opening that links to an underlying sea cave. They form as wave erosion enlarges caves and progressively extends them upward and inland until one or more vertical conduits connect the cave chamber to the surface,…

A blind thrust earthquake arises from slip on a low‑angle reverse (thrust) fault that does not rupture the ground surface; the seismogenic plane is buried, so no surface fault trace is evident. Because the causative structure lacks a visible expression at the surface, blind thrusts typically escape standard geological mapping and remain undetected until subsurface…

The Blasius boundary layer is the canonical steady, two‑dimensional laminar solution describing the viscous shear region that develops along a semi‑infinite flat plate placed parallel to a uniform free stream. Under the assumptions of steady flow, two‑dimensionality, incompressibility, laminar viscosity and a constant external velocity U aligned with the plate, a thin layer adjacent to…

The Bird’s Head plate is a minor but distinct lithospheric block that underlies the Bird’s Head Peninsula at the western end of New Guinea, and forms part of a complex mosaic of plates in eastern Indonesia. Its kinematics remain debated: some authors (e.g., Hillis and Müller) interpret the Bird’s Head as moving coherently with the…

Introduction Bioerosion denotes the biological breakdown of hard substrates—predominantly in marine settings but also on land—by organisms that bore, drill, rasp, scrape or otherwise remove material from coastlines, reefs, vessels and other rigid surfaces. At the microscale this process can be framed as cell‑driven surface degradation: activity of colonizing cells alters or removes surface layers…

Introduction The Big Bang theory is the prevailing physical framework describing the universe’s evolution from an initial state of extreme density and temperature to the present expanding cosmos. It accounts quantitatively for several key observables: the primordial abundances of light elements, the cosmic microwave background (CMB) and its anisotropies, and the emergence of large-scale structure…

Introduction A beach is a coastal or inland littoral landform composed of loose particulate material—derived from rock (sand, gravel, pebbles, shingle) and biological detritus (shells, coralline fragments)—whose grain size, shape, color and stratification record the provenance and transport history of the sediment. The distribution and internal organization of these particles reflect ongoing sedimentary processes: local…

Beach nourishment — Introduction Beach nourishment, also known as renourishment or sand replenishment, is a coastal engineering practice in which sediment—most commonly sand—is placed on eroding shorelines to replace material lost to wave action and alongshore transport. The added sediment is typically sourced from offshore, riverine, or inland deposits and distributed along the foreshore and…

Beach evolution encompasses the continuous interplay of processes that reshape shorelines of seas, lakes and rivers through both loss and gain of sediment. Mechanical breakdown by moving water—waves in marine and lacustrine environments and flow in rivers—wears away bedrock and coarser deposits, creating the sand- and silt-sized particles that constitute much beach material. Fluvial transport…

The Baltic Shield (Fennoscandian Shield) is a major segment of the East European Craton that underlies much of Fennoscandia, northwestern Russia and the northern Baltic Sea, where ancient continental basement rocks are commonly exposed at the surface. Its crust is largely composed of Archean and Proterozoic gneisses and greenstone belts, containing some of Europe’s oldest…

The Azores triple junction, centered at ~39.44°N, 29.83°W, occupies a segment of the Mid-Atlantic Ridge (MAR) west of the Strait of Gibraltar within the Azores archipelago. It marks the mutual boundary of the North American, Eurasian and African (Nubian) plates and is formed where the broadly north–south MAR is intersected by the east–southeast–trending Terceira Rift….