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Lake Vai Lahi
Vai Lahi ('' Tongan: Big water'') is the central crater lake of the Tongan island of Niuafoou. The island is the most northerly island of Tonga, is the most northerly island in the kingdom of Tonga, and is located some 570 km north of the kingdom's main island, Tongatapu. Niuafoou is annular in shape, the rim of an active volcano. The island ring encloses two large lakes, Vai Lahi and the much smaller Vai Sii (also known as Vai Mataaho), plus some eight much smaller ponds.Kempe, S., and Kasmierczak, J., "Terrestrial analogues for early planetary oceans - 5. The caldera lakes of Niuafoou", in Hanslmeier, A., Kempe, S., and Seckbac, J., (eds.) (2012) Life on Earth and other Planetary Bodies' New York: Dordrecht. Vai Lahi is a roughly circular crater lake with a diameter of 4 kilometres. Its surface, reported as 23 metres above sea level in 1935, is now believed to be close to sea level. The same survey which reported these new findings also discovered that the depth of the lake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonga
Tonga (, ; ), officially the Kingdom of Tonga ( to, Puleʻanga Fakatuʻi ʻo Tonga), is a Polynesian country and archipelago. The country has 171 islands – of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. As of 2021, according to Johnson's Tribune, Tonga has a population of 104,494, 70% of whom reside on the main island, Tongatapu. The country stretches approximately north-south. It is surrounded by Fiji and Wallis and Futuna (France) to the northwest; Samoa to the northeast; New Caledonia (France) and Vanuatu to the west; Niue (the nearest foreign territory) to the east; and Kermadec (New Zealand) to the southwest. Tonga is about from New Zealand's North Island. First inhabited roughly 2,500 years ago by the Lapita civilization, Tonga's Polynesian settlers gradually evolved a distinct and strong ethnic identity, language, and culture as the Tongan people. They were quick to establish a powerful footing acr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Crater Lake
A volcanic crater lake is a lake in a crater that was formed by explosive activity or a collapse during a volcanic eruption. Formation Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption. Lakes in maars fill medium-sized craters where an eruption deposited debris around a vent. Crater lakes form as the created depression, within the crater rim, is filled by water. The water may come from precipitation, groundwater circulation (often hydrothermal fluids in the case of volcanic craters) or melted ice. Its level rises until an equilibrium is reached between the rates of incoming and outgoing water. Sources of water loss singly or together may include evaporation, subsurface seepage, and, in places, surface leakage or overflow when the lake level reaches the lowest point on its rim. At such a saddle location, the upper portion of the lake is contained only by its adjacent natural volcanic dam; continued leakage through or surface outflow ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niuafoʻou
Niuafoou (meaning ''many new coconuts'') is the northernmost island in the kingdom of Tonga. One of the Niua Islands, it is located in the southern Pacific Ocean between Fiji and Samoa, north of Tongatapu island group and northwest of Vavaʻu. It is a volcanic rim island with an area of and a population of 431 (as of 2021). The volcano is active and has erupted regularly since 1814, with its last major eruption in 1985. The Niuafoʻou language is spoken on the island. Geography Niuafoou is a volcano located on an underwater ridge west of the line along which all the other volcanoes of Tonga are ranged. The island contains a steep-sided caldera; its rim is over high. It rises to a height of at Mokotu. The coastline is rocky and steep, with only a few beaches, all of which are stony, with black sand. The only landing place on the island is at the end of a lava flow in Futu, which is in the western part of the island. All the villages are in the north and east. Public places ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongan Language
Tongan (English pronunciation: or ; ') is an Austronesian language of the Polynesian branch native to the island nation of Tonga. It has around 187,000 speakers. It uses the word order verb–subject–object. Related languages Tongan is one of the multiple languages in the Polynesian branch of the Austronesian languages, along with Hawaiian, Māori, Samoan and Tahitian, for example. Together with Niuean, it forms the Tongic subgroup of Polynesian. Tongan is unusual among Polynesian languages in that it has a so-called ''definitive accent''. As with all Polynesian languages, Tongan has adapted the phonological system of proto-Polynesian. # Tongan has retained the original proto-Polynesian *h, but has merged it with the original *s as . (The found in modern Tongan derives from *t before high front vowels). Most Polynesian languages have lost the original proto-Polynesian glottal stop ; however, it has been retained in Tongan and a few other languages including Rapa Nui ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tongatapu
Tongatapu is the main island of Tonga and the site of its capital, Nukualofa. It is located in Tonga's southern island group, to which it gives its name, and is the country's most populous island, with 74,611 residents (2016), 70.5% of the national population, on . Based on Google Earth Pro, its maximum elevation is at least above sea level along Liku Road at 21 degrees 15 minutes and 55.7 seconds south 175 degrees 08 minutes 06.4 seconds west, but could be even higher somewhere else. Tongatapu is Tonga's centre of government and the seat of its monarchy. Tongatapu has experienced more rapid economic development than the other islands of Tonga, and has thus attracted many internal migrants from them. Geography The island is (or including neighbouring islands) and rather flat, as it is built of coral limestone. The island is covered with thick fertile soil consisting of volcanic ash from neighbouring volcanoes. At the steep coast of the south, heights reach an average of , a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alkali
In chemistry, an alkali (; from ar, القلوي, al-qaly, lit=ashes of the saltwort) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The adjective alkaline, and less often, alkalescent, is commonly used in English as a synonym for basic, especially for bases soluble in water. This broad use of the term is likely to have come about because alkalis were the first bases known to obey the Arrhenius definition of a base, and they are still among the most common bases. Etymology The word "alkali" is derived from Arabic ''al qalīy'' (or ''alkali''), meaning ''the calcined ashes'' (see calcination), referring to the original source of alkaline substances. A water-extract of burned plant ashes, called potash and composed mostly of potassium carbonate, was mildly basic. After heating this substance with calcium hydroxide (''slaked lime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lakes Of Tonga
A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger oceans, they do form part of the Earth's water cycle. Lakes are distinct from lagoons, which are generally coastal parts of the ocean. Lakes are typically larger and deeper than ponds, which also lie on land, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which usually flow in a channel on land. Most lakes are fed and drained by rivers and streams. Natural lakes are generally found in mountainous areas, rift zones, and areas with ongoing glaciation. Other lakes are found in endorheic basins or along the courses of mature rivers, where a river channel has widened into a basin. Some parts of the world have many lakes formed by the chaotic drainage patterns left over from the last ice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Volcanic Crater Lakes
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates are diverging or converging, and most are found underwater. For example, a mid-ocean ridge, such as the Mid-Atlantic Ridge, has volcanoes caused by divergent tectonic plates whereas the Pacific Ring of Fire has volcanoes caused by convergent tectonic plates. Volcanoes can also form where there is stretching and thinning of the crust's plates, such as in the East African Rift and the Wells Gray-Clearwater volcanic field and Rio Grande rift in North America. Volcanism away from plate boundaries has been postulated to arise from upwelling diapirs from the core–mantle boundary, deep in the Earth. This results in hotspot volcanism, of which the Hawaiian hotspot is an example. Volcanoes are usually not created where two tectonic plates slide pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
