Coastline in the context of Geology

Lesbos or Lesvos (Greek: Λέσβος, romanized: Lésvos [ˈlezvos]) is a Greek island located in the northeastern Aegean Sea. It has an area of 1,633 km (631 sq mi), with approximately 400 kilometres (249 miles) of coastline, making it the third largest island in Greece and the eighth largest in the Mediterranean. It is separated from Asia Minor by the narrow Mytilini Strait. On the southeastern coast is the island's capital and largest city, Mytilene (Μυτιλήνη), whose name is also used for the island as a whole. Lesbos is a separate regional unit with the seat in Mytilene, which is also the capital of the larger North Aegean region. The region includes the islands of Lesbos, Chios, Ikaria, Lemnos, and Samos. The total population of the island was 83,755 in 2021. A third of the island's inhabitants live in the capital, while the remainder are concentrated in small towns and villages. The largest are Plomari, Agia Paraskevi, Polichnitos, Agiassos, Eresos, Gera, and Molyvos (the ancient Mythimna).

According to later Greek writers, Mytilene was founded in the 11th century BC by the family Penthilidae, who arrived from Thessaly and ruled the city-state until a popular revolt (590–580 BC) led by Pittacus of Mytilene ended their rule. In fact, the archaeological and linguistic records may indicate a late Iron Age arrival of Greek settlers, although references in Late Bronze Age Hittite archives indicate a likely Greek presence then. According to Homer's Iliad, Lesbos was part of the kingdom of Priam, which ruled from Troy. In the Middle Ages, it was under Byzantine and then Genoese rule. Lesbos was conquered by the Ottoman Empire in 1462. The Ottomans then ruled the island until the First Balkan War in 1912, when it became part of the Kingdom of Greece.

In geography, a pole of inaccessibility is the farthest (or most difficult to reach) location in a given landmass, sea, or other topographical feature, starting from a given boundary, relative to a given criterion. A geographical criterion of inaccessibility marks a location that is the most challenging to reach according to that criterion. Often it refers to the most distant point from the coastline, implying the farthest point into a landmass from the shore, or the farthest point into a body of water from the shore. In these cases, a pole of inaccessibility is the center of a maximally large circle that can be drawn within an area of interest only touching but not crossing a coastline. Where a coast is imprecisely defined, the pole will be similarly imprecise.

Coastal erosion is the loss or displacement of land, or the long-term removal of sediment and rocks along the coastline due to the action of waves, currents, tides, wind-driven water, waterborne ice, or other impacts of storms. The landward retreat of the shoreline can be measured and described over a temporal scale of tides, seasons, and other short-term cyclic processes. Coastal erosion may be caused by hydraulic action, abrasion, impact and corrosion by wind and water, and other forces, natural or unnatural.

On non-rocky coasts, coastal erosion results in rock formations in areas where the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones, which typically result in landforms such as tunnels, bridges, columns, and pillars. Over time the coast generally evens out. The softer areas fill up with sediment eroded from hard areas, and rock formations are eroded away. Also erosion commonly happens in areas where there are strong winds, loose sand, and soft rocks. The blowing of millions of sharp sand grains creates a sandblasting effect. This effect helps to erode, smooth and polish rocks. The definition of erosion is grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.

South Africa, officially the Republic of South Africa (RSA), is the southernmost country in Africa. Its nine provinces are bounded to the south by 2,798 kilometres (1,739 miles) of coastline that stretches along the South Atlantic and Indian Ocean; to the north by the neighbouring countries of Namibia, Botswana, and Zimbabwe; to the east and northeast by Mozambique and Eswatini; and it encloses Lesotho.

Covering an area of 1,221,037 square kilometres (471,445 square miles), the country has a population of over 63 million people (the 6th largest in Africa). Pretoria is the administrative capital, while Cape Town, as the seat of Parliament, is the legislative capital, and Bloemfontein is regarded as the judicial capital. The largest, most populous city is Johannesburg, followed by Cape Town and Durban.

Dead zones are hypoxic (low-oxygen) areas in the world's oceans and large lakes. Hypoxia occurs when dissolved oxygen (DO) concentration falls to or below 2 mg of O₂/liter. When a body of water experiences hypoxic conditions, aquatic flora and fauna begin to change behavior in order to reach sections of water with higher oxygen levels. Once DO declines below 0.5 mg O₂/liter in a body of water, mass mortality occurs. With such a low concentration of DO, these bodies of water fail to support the aquatic life living there. Historically, many of these sites were naturally occurring. However, in the 1970s, oceanographers began noting increased instances and expanses of dead zones. These occur near inhabited coastlines, where aquatic life is most concentrated.

Coastal regions, such as the Baltic Sea, the northern Gulf of Mexico, and the Chesapeake Bay, as well as large enclosed water bodies like Lake Erie, have been affected by deoxygenation due to eutrophication. Excess nutrients are put into these systems by rivers, ultimately from urban and agricultural runoff and exacerbated by deforestation. These nutrients lead to high productivity that produces organic material that sinks to the bottom and is respired. The respiration of that organic material uses up the oxygen and causes hypoxia or anoxia.

Greece is characterized by an extremely fragmented, rugged landscape hosting a great diversity of ecosystems and an outstanding biodiversity. Almost 5% of its extensive coastline consists of ecologically sensitive wetlands. Two thirds of the total population live no further than 2 km from the coast and most of the important urban centers are coastal, while almost all of the tourist infrastructure is divided among islands and the coastal mainland.

Goa (/ˈɡoʊ.ə/ GOH-ə; Konkani: [ɡõːj]; Portuguese: [ˈɡoɐ] ) is a state on the southwestern coast of India within the Konkan region, geographically separated from the Deccan highlands by the Western Ghats. It is bordered by the Indian states of Maharashtra to the north and Karnataka to the east and south, with the Arabian Sea forming its western coastline. It is India's smallest state by area and fourth-smallest by population. Panaji (also Panjim) is the state's capital, while Vasco da Gama is its largest city by population. The state's official language is Konkani, spoken by the majority of its inhabitants.

The Portuguese, who first voyaged to the subcontinent in the early 16th century as merchants, conquered it shortly thereafter. Goa became an overseas territory of the Portuguese Empire and part of what was then known as Portuguese India, remaining under Portuguese rule for approximately 451 years until its annexation by India in December 1961. The historic city of Margão, or Madgaon, still reflects the cultural legacy of colonisation.

Odisha (Odia: oṛiśā, pronounced [oˈɽisa] ) is a state located in Eastern India. It is the eighth-largest state by area, and the eleventh-largest by population, with over 41 million inhabitants. The state also has the third-largest population of Scheduled Tribes in India. It neighbours the states of Jharkhand and West Bengal to the north, Chhattisgarh to the west, and Andhra Pradesh to the south. Odisha has a coastline of 485 kilometres (301 mi) along the Bay of Bengal in the Indian Ocean. The region is also known as Utkaḷa and is mentioned by this name in India's national anthem, Jana Gana Mana.

The ancient kingdom of Kalinga, which was invaded by the Mauryan Emperor Ashoka in 261 BCE resulting in the Kalinga War, coincides with the borders of modern-day Odisha. The modern boundaries of Odisha were demarcated by the British Indian government, the Orissa Province was established on 1 April 1936, consisting of the Odia-speaking districts of Bihar and Orissa Province, Madras Presidency and Central Provinces. Utkala Divas (lit. 'Odisha Day') is celebrated on 1 April. Cuttack was made the capital of the region by Anantavarman Chodaganga in c. 1135, after which the city was used as the capital by many rulers, through the British era until 1948. Thereafter, Bhubaneswar became the capital of Odisha.

Shimane Prefecture (島根県, Shimane-ken; Japanese pronunciation: [ɕiꜜ.ma.ne, ɕi.ma.neꜜ.keɴ]) is a prefecture of Japan located in the Chūgoku region of Honshu. Shimane Prefecture is the second-least populous prefecture of Japan at 665,205 (February 1, 2021) and has a geographic area of 6,708.26 km. Shimane Prefecture borders Yamaguchi Prefecture to the southwest, Hiroshima Prefecture to the south, and Tottori Prefecture to the east.

Matsue is the capital and largest city of Shimane Prefecture, with other major cities including Izumo, Hamada, and Masuda. Shimane Prefecture contains the majority of the Lake Shinji-Nakaumi metropolitan area centered on Matsue, and with a population of approximately 600,000 is Japan's third-largest metropolitan area on the Sea of Japan coast after Niigata and Greater Kanazawa. Shimane Prefecture is bounded by the Sea of Japan coastline on the north, where two-thirds of the population live, and the Chūgoku Mountains on the south. Shimane Prefecture governs the Oki Islands in the Sea of Japan which juridically includes the disputed Liancourt Rocks (竹島, Takeshima). Shimane Prefecture is home to Izumo-taisha, one of the oldest Shinto shrines in Japan, and the Tokugawa-era Matsue Castle.

The coastline paradox is the counterintuitive observation that the coastline of a landmass does not have a well-defined length or perimeter. This results from the fractal curve–like properties of coastlines; i.e., the fact that a coastline typically has a fractal dimension. Although the "paradox of length" was previously noted by Hugo Steinhaus, the first systematic study of this phenomenon was by Lewis Fry Richardson, and it was expanded upon by Benoit Mandelbrot.

The measured length of the coastline depends on the method used to measure it and the degree of cartographic generalization. Since a landmass has features at all scales, from hundreds of kilometers in size to tiny fractions of a millimeter and below, there is no obvious size of the smallest feature that should be taken into consideration when measuring, and hence no single well-defined perimeter to the landmass. Various approximations exist when specific assumptions are made about minimum feature size.

The White Cliffs of Dover are the region of English coastline facing the Strait of Dover and France. The cliff face, which reaches a height of 350 feet (110 m), owes its striking appearance to its composition of chalk accented by streaks of black flint, deposited during the Late Cretaceous. The cliffs, on both sides of the town of Dover in Kent, stretch for eight miles (13 km). The White Cliffs of Dover form part of the North Downs. A section of coastline encompassing the cliffs was purchased by the National Trust in 2016.

The cliffs are part of the Dover to Kingsdown Cliffs Site of Special Scientific Interest and Special Area of Conservation. The point where Great Britain is closest to continental Europe, on a clear day the cliffs are visible from France, approximately 20 miles (32 km) away. A celebrated UK landmark, the cliffs have featured on commemorative postage stamps issued by the Royal Mail, including in their British coastline series in 2002 and UK A-Z series in 2012.

Lakshadweep (Malayalam: [lɐkʂɐd̪βʷiːbɨ̆]) is a union territory of India. It is an archipelago of 36 islands divided into three island subgroups: the Amindivi Islands in the north, the Laccadive Islands (separated from Amindivi roughly by the 11th parallel north), and the atoll of Minicoy to the south of the Nine Degree Channel. The islands are located between the Arabian Sea to the west and the Laccadive Sea to the east, about 220–440 km (140–270 mi) off the Malabar Coast of mainland India.

The islands occupy a total land area of approximately 32.62 km (12.59 sq mi) with a population of 64,473 as per the 2011 census across the ten inhabited islands. There is a 132 km (82 mi) long coastline with a lagoon area of 4,200 km (1,600 sq mi), territorial waters of 20,000 km (7,700 sq mi) and an exclusive economic zone of 400,000 km (150,000 sq mi). Lakshadweep is the northernmost island group of the exposed undersea mountain range, the Chagos-Lakshadweep Ridge. The entire union territory is administered as a single district with Kavaratti as its capital.

The 1900 Galveston hurricane, also known as the Great Galveston hurricane and the Galveston Flood, and known regionally as the Great Storm of 1900 or the 1900 Storm, was a catastrophic tropical cyclone that became the deadliest natural disaster in the history of the United States. The strongest storm of the 1900 Atlantic hurricane season, it left between 6,000 and 12,000 fatalities in the United States; the number most cited in official reports is 8,000. Most of these deaths occurred in and near Galveston, Texas, after the storm surge inundated the coastline and the island city with 8 to 12 ft (2.4 to 3.7 m) of water. As of 2025, it remains the fourth deadliest Atlantic hurricane on record, behind Hurricane Fifi of 1974. In addition to the number killed, the storm destroyed about 7,000 buildings of all uses in Galveston, which included 3,636 demolished homes; every dwelling in the city suffered some degree of damage. The hurricane left approximately 10,000 people in the city homeless, out of a total population of fewer than 38,000. The disaster ended the Golden Era of Galveston. The hurricane alarmed potential investors, who turned to Houston instead. In response to the storm, three engineers designed and oversaw plans to raise the Gulf of Mexico shoreline of Galveston Island by 17 ft (5.2 m) and erect a 10 mi (16 km) seawall.

On August 27, 1900, a ship east of the Windward Islands detected a tropical cyclone, the first observed that year. The system proceeded to move steadily west-northwestward and entered the northeastern Caribbean on August 30. It made landfall in the Dominican Republic as a weak tropical storm on September 2. It weakened slightly while crossing Hispaniola, before re-emerging into the Caribbean Sea later that day. On September 3, the cyclone struck modern-day Santiago de Cuba Province and then slowly drifted along the southern coast of Cuba. Upon reaching the Gulf of Mexico on September 6, the storm strengthened into a hurricane. Significant intensification followed and the system peaked as a Category 4 hurricane with maximum sustained winds of 145 mph (235 km/h) on September 8. Early on the next day, it made landfall to the south of Houston. The cyclone weakened quickly after moving inland and fell to tropical storm intensity late on September 9. The storm turned east-northeastward and became extratropical over Iowa on September 11. The extratropical system strengthened while accelerating across the Midwestern United States, New England, and Eastern Canada before reaching the Gulf of Saint Lawrence on September 13. After striking Newfoundland later that day, the extratropical storm entered the far North Atlantic Ocean and weakened, with the remnants last observed near Iceland on September 15.

The Republic of Haiti comprises the western three-eighths of the island of Hispaniola, west of the Dominican Republic. Haiti is positioned east of the neighboring island of Cuba, between the Caribbean Sea and the North Atlantic Ocean.

Haiti's total area is 27,560 square kilometres (10,641 sq mi), of which 27,560 square kilometres (10,641 sq mi) is land and 190 square kilometres (73 sq mi) is water. Haiti has 1,771 km (1,100 mi) of coastline and a 360 kilometres (224 mi)-border with the Dominican Republic.

In mathematics, a self-similar object is exactly or approximately similar to a part of itself (i.e., the whole has the same shape as one or more of the parts). Many objects in the real world, such as coastlines, are statistically self-similar: parts of them show the same statistical properties at many scales. Self-similarity is a typical property of fractals. Scale invariance is an exact form of self-similarity where at any magnification there is a smaller piece of the object that is similar to the whole. For instance, a side of the Koch snowflake is both symmetrical and scale-invariant; it can be continually magnified 3x without changing shape.

Peitgen et al. explain the concept as such: