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43-515: The Hawaiian Trough , otherwise known as the Hawaiian Deep , is a moat -like depression of the seafloor surrounding the Hawaiian Islands . The weight from the volcanic island chain depresses the plastic lithosphere that is already weakened by the underlying thermal hotspot , causing subsidence to occur. The location with the greatest rate of subsidence is directly above the hotspot with

86-402: A basic method of pest control in bonsai , a moat may be used to restrict access of crawling insects to the bonsai. [REDACTED] Media related to Moats at Wikimedia Commons Battering ram A battering ram is a siege engine that originated in ancient times and was designed to break open the masonry walls of fortifications or splinter their wooden gates. In its simplest form,

129-477: A battering ram is just a large, heavy log carried by several people and propelled with force against an obstacle; the ram would be sufficient to damage the target if the log were massive enough and/or it were moved quickly enough (that is, if it had enough momentum ). Later rams encased the log in an arrow-proof, fire-resistant canopy mounted on wheels. Inside the canopy, the log was swung from suspensory chains or ropes. Rams proved effective weapons of war because at

172-650: A combination of ramparts and moats, called Iya, used as a defence of the capital Benin City in present-day Edo State of Nigeria. It was considered the largest man-made structure lengthwise, second only to the Great Wall of China and the largest earthwork in the world. Recent work by Patrick Darling has established it as the largest man-made structure in the world, larger than Sungbo's Eredo , also in Nigeria. It enclosed 6,500 km (2,500 sq mi) of community lands. Its length

215-458: A fortress under the protection of a mobile roofed structure, carrying a long pole that may represent a simple battering ram. During the Iron Age , in the ancient Middle East and Mediterranean, the battering ram's log was slung from a wheeled frame by ropes or chains so that it could be made more massive and be more easily bashed against its target. Frequently, the ram's point would be reinforced with

258-639: A key element used in French Classicism and Beaux-Arts architecture dwellings, both as decorative designs and to provide discreet access for service. Excellent examples of these can be found in Newport, Rhode Island at Miramar (mansion) and The Elms , as well as at Carolands , outside of San Francisco, California, and at Union Station in Toronto , Ontario, Canada. Additionally, a dry moat can allow light and fresh air to reach basement workspaces, as for example at

301-451: A layer of landslide debris. This layer contributes to the bulk of the sediment in the Trough. In the fourth and final stage, volcanic activity and subsistence effectively ends, and sediment deposits brought by turbidity currents, create a ponded unit in the deepest part of the Trough. This top layer is primary composed of turbidite and pelagic sediments. The largest mass wasting events, such as

344-471: A metal head or cap while vulnerable parts of the shaft were bound with strengthening metal bands. Vitruvius details in his text De architectura that Ceras the Carthaginian was the first to make a ram with a wooden base with wheels and a wooden superstructure, with the ram hung within. This structure moved so slowly, however, that he called it the testudo (Latin for "tortoise"). Another type of ram

387-461: A ram, as used by Alexander the Great , is described by Vitruvius. Alternatives to the battering ram included the drill , the sapper's mouse, the pick, the siege hook , and the hunting ram. These devices were smaller than a ram and could be used in confined spaces. Battering rams had an important effect on the evolution of defensive walls, which were constructed ever more ingeniously in a bid to nullify

430-539: A rate of about 0.1 inches (2.5 millimeters) per year. The Hawaiian Trough is about 18,045 feet (5,500 meters) deep and has a radius of about 8.7 miles (14.0 km). The subsiding lithosphere is balanced out and through the concept of isostasy a part of the crust surrounding the trough is levered upwards creating the Hawaiian Arch. The Hawaiian Arch extends about 656 feet (200 meters) above the surrounding ocean floor, and contains tilted coral reefs . The Hawaiian Trough

473-536: A spoof history essay by Professor David Daube written for The Oxford Magazine in 1956, which was widely believed despite obvious improbabilities (e.g., planning to cross the River Severn by running the ram down a hill at speed, although the river is about 30 m (100 feet) wide at this point). Battering rams still have a use in modern times. Police forces often employ small, one-man or two-man metal rams, known as enforcers , for forcing open locked portals or effecting

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516-724: A vertical outer retaining wall rising direct from the moat, is an extended usage of the ha-ha of English landscape gardening. In 2004, plans were suggested for a two-mile moat across the southern border of the Gaza Strip to prevent tunnelling from Egyptian territory to the border town of Rafah . In 2008, city officials in Yuma, Arizona planned to dig out a two-mile stretch of a 180-hectare (440-acre) wetland known as Hunters Hole to control immigrants coming from Mexico. Researchers of jumping spiders , which have excellent vision and adaptable tactics, built water-filled miniature moats, too wide for

559-436: A wall or gate, or by using grappling hooks to immobilize the ram's log. Alternatively, the ram could be set ablaze, doused in fire-heated sand, pounded by boulders dropped from battlements or invested by a rapid sally of troops. Some battering rams were not slung from ropes or chains, but were instead supported by rollers. This allowed the ram to achieve a greater speed before striking its target, making it more destructive. Such

602-418: Is characterized by a bedded layer of volcanoclastic material that fills the Trough as it quickly subsides due to large influxes of material from nearby volcanos. The majority of material in this layer was transported by turbidity currents that flow along the axis of the moat and transport material from mass wasting events. During the third stage, the depression fills with slumps and debris avalanches which creates

645-469: Is filled with a stratified sedimentary section >2 km thick that was deposited in 4 sequential stages. The first (bottom) stage is a basal layer composed of 50 –100 m of primarily pelagic sediment. This layer was slowly deposited on the 80-Ma oceanic crust before the depression formed. The sediment in this layer is from a variety of different sources including wind blown material, slowly setting fine-grained sediment, and biogenic debris. The second stage

688-709: The James Farley Post Office in New York City . Whilst moats are no longer a significant tool of warfare, modern architectural building design continues to use them as a defence against certain modern threats, such as terrorist attacks from car bombs and improvised fighting vehicles . For example, the new location of the Embassy of the United States in London , opened in 2018, includes a moat among its security features -

731-717: The Mississippian culture as the outer defence of some fortified villages. The remains of a 16th-century moat are still visible at the Parkin Archeological State Park in eastern Arkansas . The Maya people also used moats, for example in the city of Becan . European colonists in the Americas often built dry ditches surrounding forts built to protect important landmarks, harbours or cities (e.g. Fort Jay on Governors Island in New York Harbor ). Dry moats were

774-641: The 9th century BC. The defenders of a town wall are trying to set the ram alight with torches and have also put a chain under it. The attackers are trying to pull on the chain to free the ram, while the aforementioned wet hides on the canopy provide protection against the flames. By the time the Kushites made their incursions into Egypt, c.  715 BC , walls, siege tactics and equipment had undergone many changes. Early shelters protecting sappers armed with poles trying to breach mudbrick ramparts gave way to battering rams. The first confirmed use of rams in

817-528: The Great Wall of China, and consumed a hundred times more material than the Great Pyramid of Cheops. They took an estimated 150 million hours of digging to construct, and are perhaps the largest single archaeological phenomenon on the planet. Japanese castles often have very elaborate moats, with up to three moats laid out in concentric circles around the castle and a host of different patterns engineered around

860-511: The Mediterranean Basin, featuring in this case the simultaneous employment of siege towers to shelter the rammers from attack, occurred on the island of Sicily in 409 BC, at the Selinus siege. Defenders manning castles, forts or bastions would sometimes try to foil battering rams by dropping obstacles in front of the ram, such as a large sack of sawdust, just before the ram's head struck

903-506: The Nuuanu-Wailau debris avalanches and the Hana slump, overfilled the moat and created a series of sub-basins. These large deposits block the lateral transport of sediment along the Trough, especially in the deepest sections. Storm surges and internal waves trigger mass wasting events from older volcanos on the western side of the ridge, earthquakes provoke this behavior from younger volcanos on

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946-559: The Occident happened from 503 to 502 BC when Opiter Verginius became consul of the Romans during the fight against Aurunci people: The following consuls, Opiter Virginius and Sp. Cassius, first endeavored to take Pometia by storm, and afterwards by raising battering rams (vineae) and other works. The second known use was in 427 BC, when the Spartans besieged Plataea . The first use of rams within

989-541: The defences – very difficult as well. Segmented moats have one dry section and one section filled with water. Dry moats that cut across the narrow part of a spur or peninsula are called neck ditches . Moats separating different elements of a castle, such as the inner and outer wards, are cross ditches . The word was adapted in Middle English from the Old French motte ( lit.   ' mound, hillock ' ) and

1032-410: The defensive system as an obstacle immediately outside the walls . In suitable locations, they might be filled with water. A moat made access to the walls difficult for siege weapons such as siege towers and battering rams , which needed to be brought up against a wall to be effective. A water-filled moat made the practice of mining – digging tunnels under the castles in order to effect a collapse of

1075-590: The eastern side. The coral reefs in the Hawaiian Trough are described as mesophotic coral ecosystems , which can be found between 100 and 500 feet below sea level. 43 percent of fish species documented at the mesophotic reefs are unique to the Hawaiian Islands. At Maui's ‘Au’au channel the largest uninterrupted mesophotic coral ecosystem was discovered, with an area larger than 3 square miles. These reefs contained many stony, reef building coral that belong to

1118-605: The effects of siege engines. Historical instances of the usage of battering rams in sieges of major cities include: There is a popular myth in Gloucester , England that the well known children's rhyme, Humpty Dumpty , is about a battering ram used in the siege of Gloucester in 1643, during the Civil War . However, the story is almost certainly untrue; during the siege, which lasted only one month, no battering rams were used, although many cannons were. The idea seems to have originated in

1161-411: The feudal period more commonly had 'dry moats' karabori ( 空堀 , lit.   ' empty moat ' ) , a trench . A tatebori ( 竪堀 , lit.   ' vertical moat ' ) is a dry moat dug into a slope. A unejo tatebori ( 畝状竪堀 , lit.   ' furrowed shape empty moat ' ) is a series of parallel trenches running up the sides of the excavated mountain, and the earthen wall, which

1204-689: The first moat built in England for more than a century. Modern moats may also be used for aesthetic or ergonomic purposes. The Catawba Nuclear Station has a concrete moat around the sides of the plant not bordering a lake. The moat is a part of precautions added to such sites after the September 11, 2001 attacks . Moats, rather than fences, separate animals from spectators in many modern zoo installations. Moats were first used in this way by Carl Hagenbeck at his Tierpark in Hamburg , Germany. The structure, with

1247-455: The genus Leptoseris, which are adapted for deep water environments. These coral environments are not greatly understood because the great depth where they exist make exploration difficult. Moat Some of the earliest evidence of moats has been uncovered around ancient Egyptian fortresses. One example is at Buhen , a settlement excavated in Nubia . Other evidence of ancient moats is found in

1290-415: The head (usually made of iron or steel and sometimes punningly shaped into the head and horns of an ovine ram ) to do more damage to a building. It was much more effective at destroying enemy walls and buildings than an uncapped ram but was heavier to carry. The earliest depiction of a possible battering ram is from the tomb of the 11th Dynasty Egyptian noble Khety, where a pair of soldiers advance towards

1333-492: The introduction of siege artillery , a new style of fortification emerged in the 16th century using low walls and projecting strong points called bastions , which was known as the trace italienne . The walls were further protected from infantry attack by wet or dry moats, sometimes in elaborate systems. When this style of fortification was superseded by lines of polygonal forts in the mid-19th century, moats continued to be used for close protection. The Walls of Benin were

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1376-583: The landscape. The outer moat of a Japanese castle typically protects other support buildings in addition to the castle. As many Japanese castles have historically been a very central part of their cities, the moats have provided a vital waterway to the city. Even in modern times the moat system of the Tokyo Imperial Palace consists of a very active body of water, hosting everything from rental boats and fishing ponds to restaurants. Most modern Japanese castles have moats filled with water, but castles in

1419-439: The later Middle Ages of siege cannons , which harnessed the explosive power of gunpowder to propel weighty stone or iron balls against fortified obstacles, spelled the end of battering rams and other traditional siege weapons. Smaller, hand-held versions of battering rams are still used today by law enforcement officers and military personnel to break open locked doors. A capped ram is a battering ram that has an accessory at

1462-540: The locals for building purposes. The walls continue to be torn down for real-estate developments. The Walls of Benin City were the world's largest man-made structure. Fred Pearce wrote in New Scientist: They extend for some 16,000 kilometres in all, in a mosaic of more than 500 interconnected settlement boundaries. They cover 6,500 square kilometres and were all dug by the Edo people. In all, they are four times longer than

1505-447: The ram against the wall when they reached it. Many battering rams had curved or slanted wooden roofs and side-screens, covered in protective materials, usually fresh wet hides. These canopies reduced the risk of the ram being set on fire, and protected the operators of the ram from arrow and spear volleys launched from above. An image of an Assyrian battering ram depicts how sophisticated attacking and defensive practices had become by

1548-460: The ruins of Babylon, and in reliefs from ancient Egypt, Assyria , and other cultures in the region. Evidence of early moats around settlements has been discovered in many archaeological sites throughout Southeast Asia, including Noen U-Loke, Ban Non Khrua Chut, Ban Makham Thae and Ban Non Wat. The use of the moats could have been either for defensive or agriculture purposes. Moats were excavated around castles and other fortifications as part of

1591-489: The spiders to jump across. Some specimens were rewarded for jumping then swimming and others for swimming only. Portia fimbriata from Queensland generally succeeded, for whichever method they were rewarded. When specimens from two different populations of Portia labiata were set the same task, members of one population determined which method earned them a reward, whilst members of the other continued to use whichever method they tried first and did not try to adapt. As

1634-402: The time wall-building materials such as stone and brick were weak in tension , and therefore prone to cracking when impacted with force. With repeated blows, the cracks would grow steadily until a hole was created. Eventually, a breach would appear in the fabric of the wall, enabling armed attackers to force their way through the gap and engage the inhabitants of the citadel. The introduction in

1677-512: Was Fort Lytton in Brisbane . As Brisbane was much more vulnerable to attack than either Sydney or Melbourne a series of coastal defences was built throughout Moreton Bay , Fort Lytton being the largest. Built between 1880 and 1881 in response to fear of a Russian invasion, it is a pentagonal fortress concealed behind grassy embankments and surrounded by a water-filled moat. Moats were developed independently by North American indigenous people of

1720-1207: Was also called doi ( 土居 , lit.   ' earth mount ' ) , was an outer wall made of earth dug out from a moat. Even today it is common for mountain Japanese castles to have dry moats. A mizubori ( 水堀 , lit.   ' water moat ' ) is a moat filled with water. Moats were also used in the Forbidden City and Xi'an in China; in Vellore Fort in India; Hsinchu in Taiwan ; and in Southeast Asia, such as at Angkor Wat in Cambodia ; Mandalay in Myanmar ; Chiang Mai in Thailand and Huế in Vietnam . The only moated fort ever built in Australia

1763-422: Was first applied to the central mound on which a castle was erected (see Motte and bailey ) and then came to be applied to the excavated ring, a 'dry moat'. The shared derivation implies that the two features were closely related and possibly constructed at the same time. The term moat is also applied to natural formations reminiscent of the artificial structure and to similar modern architectural features. With

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1806-404: Was one that maintained the normal shape and structure, but the support beams were instead made of saplings that were lashed together. The frame was then covered in hides as normal to defend from fire. The only solid beam present was the ram that was hung from the frame. The frame itself was so light that it could be carried on the shoulders of the men transporting the ram, and the same men could beat

1849-533: Was over 16,000 km (9,900 mi) of earth boundaries. It was estimated that earliest construction began in 800 and continued into the mid-15th century. The walls are built of a ditch and dike structure, the ditch dug to form an inner moat with the excavated earth used to form the exterior rampart. The Benin Walls were ravaged by the British in 1897. Scattered pieces of the walls remain in Edo, with material being used by

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