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Mount Tambora And the Year without summer 1816
Mount Tambora (or Tomboro) is an active stratovolcano, also known as a composite volcano, on Sumbawa island, Indonesia. Sumbawa is flanked both to the north and south by oceanic crust, and Tambora was formed by the active subduction zones beneath it. This raised Mount Tambora as high as 4,300 m (14,000 ft), making it one of the tallest peaks in the Indonesian archipelago, and drained off a large magma chamber inside the mountain. It took centuries to refill the magma chamber, its volcanic activity reaching its peak in April 1815.
Tambora erupted in 1815 with a rating of seven on the Volcanic Explosivity Index, making it the largest eruption since the Lake Taupo eruption in about 180 AD. It was the largest volcanic eruption in recorded history. The explosion was heard on Sumatra island (more than 2,000 km (1,200 mi) away). Heavy volcanic ash falls were observed as far away as Borneo, Sulawesi, Java and Maluku islands. Most deaths from the eruption were from starvation and disease, as the eruptive fallout ruined agricultural productivity in the local region. The death toll was at least 71,000 people (perhaps the most deadly eruption in history), of whom 11,000–12,000 were killed directly by the eruption; the often-cited figure of 92,000 people killed is believed to be an overestimate. The eruption created global climate anomalies; 1816 became known as the Year Without Summer because of the effect on North American and European weather. Agricultural crops failed and livestock died in much of the Northern Hemisphere, resulting in the worst famine of the 19th century.
During an excavation in 2004, a team of archaeologists discovered cultural remains buried by the 1815 eruption. They were kept intact beneath the 3 m (9.8 ft) deep pyroclastic deposits. At the site, dubbed the Pompeii of the East, the artefacts were preserved in the positions they had occupied in 1815.
Mount Tambora experienced several centuries of inactivity before 1815, known as dormancy, as the result of the gradual cooling of hydrous magma in a closed magma chamber. Inside the chamber at depths between 1.5–4.5 km (5,000–15,000 ft), the exsolution of a high pressure magma fluid formed during cooling and crystallisation of the magma. Overpressure of the chamber of about 4–5 kbar was generated and the temperature ranged from 700 °C–850 °C (1,300–1,500 °F).
In 1812, the caldera began to rumble and generated a dark cloud. On 5 April 1815, a moderate-sized eruption occurred, followed by thunderous detonation sounds, heard in Makassar on Sulawesi (380 kilometres or 240 miles), Batavia (now Jakarta) on Java (1,260 km or 780 mi), and Ternate on the Molucca Islands (1,400 km or 870 mi). What was first thought to be sound of firing guns was heard on 10–11 April on Sumatra island (more than 2,600 km or 1,600 mi away). On the morning of April 6, volcanic ash began to fall in East Java with faint detonation sounds lasting until 10 April.
At about 7 p.m. on 10 April, the eruptions intensified.Three columns of flame rose up and merged. The whole mountain was turned into a flowing mass of "liquid fire". Pumice stones of up to 20 centimetres (7.9 in) in diameter started to rain down at approximately 8 p.m., followed by ash at around 9–10 p.m. Hot pyroclastic flows cascaded down the mountain to the sea on all sides of the peninsula, wiping out the village of Tambora. Loud explosions were heard until the next evening, 11 April. The ash veil had spread as far as West Java and South Sulawesi. A "nitrous" odor was noticeable in Batavia and heavy tephra-tinged rain fell, finally receding between 11 and 17 April.
The explosion is estimated to have been at scale seven on the Volcanic Explosivity Index. It had roughly four times the energy of the 1883 Krakatoa eruption. An estimated 160 cubic kilometers (38 cubic miles) of pyroclastic trachyandesite was ejected, weighing approximately 1.4×1014 kg .This has left a caldera measuring 6–7 km (4–5 mi) across and 600–700 m (2,000–2,300 ft) deep. The density of fallen ash in Makassar was 636 kg/m². Before the explosion, Mount Tambora was approximately 4,300 metres (14,000 ft) high,one of the tallest peaks in the Indonesian archipelago. After the explosion, it now measures only 2,851 metres (9,350 ft).
The 1815 Tambora eruption is the largest observed eruption in recorded history (see Table I, for comparison). The explosion was heard 2,600 kilometres (1,600 mi) away, and ash fell at least 1,300 kilometres (810 mi) away.Pitch darkness was observed as far away as 600 kilometres (370 mi) from the mountain summit for up to two days. Pyroclastic flows spread at least 20 kilometres (12 mi) from the summit.
All vegetation on the island was destroyed. Uprooted trees, mixed with pumice ash, washed into the sea and formed rafts of up to 5 kilometres (3.1 mi) across. One pumice raft was found in the Indian Ocean, near Calcutta on 1 and 3 October 1815. Clouds of thick ash still covered the summit on 23 April. Explosions ceased on 15 July, although smoke emissions were still observed as late as 23 August. Flames and rumbling aftershocks were reported in August 1819, four years after the event.
A moderate-sized tsunami struck the shores of various islands in the Indonesian archipelago on 10 April, with a height of up to 4 metres (13 ft) in Sanggar at around 10 p.m. A tsunami of 1–2 m (3–6 ft) in height was reported in Besuki, East Java, before midnight, and one of 2 metres (6.6 ft) in height in the Molucca Islands.
The eruption column reached the stratosphere, an altitude of more than 43 km (140,000 ft).[4] The coarser ash particles fell 1 to 2 weeks after the eruptions, but the finer ash particles stayed in the atmosphere from a few months up to a few years at an altitude of 10–30 km (33,000–100,000 ft). Longitudinal winds spread these fine particles around the globe, creating optical phenomena. Prolonged and brilliantly colored sunsets and twilights were frequently seen in London, England between 28 June and 2 July 1815 and 3 September and 7 October 1815. The glow of the twilight sky typically appeared orange or red near the horizon and purple or pink above.
The estimated number of deaths varies depending on the source. Zollinger (1855) puts the number of direct deaths at 10,000, probably caused by pyroclastic flows. On Sumbawa island, there were 38,000 deaths due to starvation, and another 10,000 deaths occurred due to disease and hunger on Lombok island. Petroeschevsky (1949) estimated about 48,000 and 44,000 people were killed on Sumbawa and Lombok, respectively.Several authors use Petroeschevsky's figures, such as Stothers (1984), who cites 88,000 deaths in total. However, Tanguy et al.. (1998) claimed Petroeschevsky's figures to be unfounded and based on untraceable references. Tanguy revised the number solely based on two credible sources, q.e., Zollinger, who himself spent several months on Sumbawa after the eruption, and Raffles's notes. Tanguy pointed out that there may have been additional victims on Bali and East Java because of famine and disease. Their estimate was 11,000 deaths from direct volcanic effects and 49,000 by post-eruption famine .
Year Without a Summer
The Year Without a Summer (also known as the Poverty Year, Eighteen Hundred and Froze to Death, and the Year There Was No Summer) was 1816, in which severe summer climate abnormalities destroyed crops in Northern Europe, the Northeastern United States and eastern Canada. Historian John D. Post has called this "the last great subsistence crisis in the Western world".
Most consider the climate anomaly to have been caused by a combination of a historic low in solar activity and a volcanic winter event; the latter caused by a succession of major volcanic eruptions capped off by the Mount Tambora eruption of 1815, the largest known eruption in over 1,600 years.
The unusual climatic aberrations of 1816 had the greatest effect on the Northeastern United States, New England, the Canadian Maritimes, Newfoundland, and Northern Europe. Typically, the late spring and summer of the northeastern U.S. and southeastern Canada are relatively stable: temperatures (average of both day and night) average about 68–77 °F (20–25 °C), and rarely fall below 41 °F (5 °C). Summer snow is an extreme rarity, though May flurries sometimes occur.
In May 1816, however, frost killed off most of the crops that had been planted, and in June two large snowstorms in eastern Canada and New England resulted in many human deaths. Nearly a foot (30 cm) of snow was observed in Quebec City in early June, with consequent additional loss of crops—most summer growing plants have cell walls which rupture in a mild frost, let alone a snowstorm coating the soils. The result was regional malnutrition, starvation, epidemic, and increased mortality—in short, famine.
In July and August, lake and river ice were observed as far south as Pennsylvania. Rapid, dramatic temperature swings were common, with temperatures sometimes reverting from normal or above-normal summer temperatures as high as 95 °F (35 °C) to near-freezing within hours. Even though farmers south of New England did succeed in bringing some crops to maturity, maize and other grain prices rose dramatically. Oats, for example, rose from 12¢ a bushel ($3.40/m³) the previous year to 92¢ a bushel ($26/m³)—nearly eight times as much—and oats are a necessary staple for an economy dependent upon horses for primary transportation. Those areas suffering local crop failures then had to deal with the lack of roads in the early 19th century, preventing any easy importation of bulky food stuffs.
In China, the cold weather killed trees, rice crops and even water buffalo, especially in northern China. Floods destroyed many remaining crops. Mount Tambora’s eruption disrupted China’s monsoon season, resulting in overwhelming floods in the Yangtze Valley in 1816. In India the delayed summer monsoon caused late torrential rains that aggravated the spread of cholera from a region near the River Ganges in Bengal to as far as Moscow.
In the ensuing bitter winter of 1817, when the thermometer dropped to -26°F (-32 °C), the waters of New York's Upper Bay froze so hard that horse-drawn sleighs were driven across Buttermilk Channel from Brooklyn to Governors Island.
The effects were widespread and lasted beyond the winter. In eastern Switzerland, the summers of 1816 and 1817 were so cool that an ice dam formed below a tongue of the Giétroz glacier high in the Val de Bagnes; in spite of the efforts of the engineer Ignaz Venetz to drain the growing lake, the ice dam collapsed catastrophically in June 1818.
As a consequence of the series of volcanic eruptions, crops in the above cited areas had been poor for several years; the final blow came in 1815 with the eruption of Tambora. In America, many historians cite the "Year Without a Summer" as a primary motivation for the western movement and rapid settlement of what is now western and central New York and the American Midwest. Many New Englanders were wiped out by the year, and tens of thousands struck out for the richer soil and better growing conditions of the Upper Midwest (then the Northwest Territory).
Europe, still recuperating from the Napoleonic Wars, suffered from food shortages. Food riots broke out in Britain and France and grain warehouses were looted. The violence was worst in landlocked Switzerland, where famine caused the government to declare a national emergency. Huge storms, abnormal rainfall with floodings of the major rivers of Europe (including the Rhine) are attributed to the event, as was the frost setting in during August 1816. A BBC documentary using figures compiled in Switzerland estimated that fatality rates in 1816 were twice that of average years, giving an approximate European fatality total of 200,000 deaths.
The eruption of Tambora also caused Hungary to experience brown snow. Italy experienced something similar, with red snow falling throughout the year. The cause of this is believed to have been volcanic ash in the atmosphere.
In China, unusually low temperatures in summer and fall devastated rice production in Yunnan province in the southwest, resulting in widespread famine. Fort Shuangcheng, now in Heilongjiang province, reported fields disrupted by frost and conscripts deserting as a result. Summer snowfall was reported in various locations in Jiangxi and Anhui provinces, both in the south of the country. In Taiwan, which has a tropical climate, snow was reported in Hsinchu and Miaoli, while frost was reported in Changhua.
High levels of ash in the atmosphere led to unusually spectacular sunsets during this period, a feature celebrated in the paintings of J. M. W. Turner. It has been theorised that it was this that gave rise to the yellow tinge that is predominant in his paintings such as Chichester Canal circa 1828. A similar phenomenon was observed after the 1883 Krakatoa eruption, and on the West Coast of the United States following the 1991 eruption of Mount Pinatubo in the Philippines.
The lack of oats to feed horses may have inspired the German inventor Karl Drais to research new ways of horseless transportation, which led to the invention of the Draisine or velocipede. This was the ancestor of the modern bicycle and a step towards mechanized personal transport.
The crop failures of the “Year without Summer” forced the family of Joseph Smith to move from Sharon, Vermont to Palmyra, New York, precipitating a series of events culminating in the publication of the Book of Mormon and the founding of the Church of Jesus Christ of Latter-day Saints.
In July 1816 "incessant rainfall" during that "wet, ungenial summer" forced Mary Shelley, John William Polidori and their friends to stay indoors for much of their Swiss holiday. They decided to have a contest, seeing who could write the scariest story, leading Shelley to write Frankenstein, or The Modern Prometheus and Polidori to write The Vampyre.
The Year without a Summer also inspired Lord Byron to write his 1816 poem Darkness.
The chemist Justus von Liebig, who had experienced the famine as a child in Darmstadt, later studied the nutrition of plants and introduced mineral fertilizers.
Very interesting website about The year without Summer : The Weather Doctor .
Nasa images Tambora Caldera : Tambora Caldera
Source : Wikipedia
Toba Super Volcano Impact
Yellowstone Super Volcano
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Yellowstone Super Volcano
The Yellowstone Caldera is the volcanic caldera in Yellowstone National Park in the United States. The caldera is located in the northwest corner of Wyoming, in which the vast majority of the park is contained. The major features of the caldera measure about 55 kilometers (34 mi) by 72 kilometers (45 mi) as determined by geological field work conducted by Bob Christiansen of the United States Geological Survey in the 1960s and 1970s. After a BBC television science program coined the term supervolcano in 2005, it has often been referred to as the Yellowstone Supervolcano.
Yellowstone, like Hawaii, is believed to lie on top of an area called a hotspot where light, hot, molten mantle rock rises towards the surface. While the Yellowstone hotspot is now under the Yellowstone Plateau, it previously helped create the eastern Snake River Plain (to the west of Yellowstone) through a series of huge volcanic eruptions. Although the hotspot's apparent motion is to the east-northeast, the North American Plate is really moving west-southwest over the stationary hotspot deep underneath.
Over the past 17 million years or so, this hotspot has generated a succession of violent eruptions and less violent floods of basaltic lava. Together these eruptions have helped create the eastern part of the Snake River Plain from a once-mountainous region. At least a dozen or so of these eruptions were so massive that they are classified as supereruptions. Volcanic eruptions sometimes empty their stores of magma so swiftly that they cause the overlying land to collapse into the emptied magma chamber, forming a geographic depression called a caldera. Calderas formed from explosive supereruptions can be as wide and deep as mid- to large-sized lakes and can be responsible for destroying broad swaths of mountain ranges.
The oldest identified caldera remnant straddles the border near McDermitt, Nevada-Oregon. Progressively younger caldera remnants, most grouped in several overlapping volcanic fields, extend from the Nevada-Oregon border through the eastern Snake River Plain and terminate in the Yellowstone Plateau. One such caldera, the Bruneau-Jarbidge caldera in southern Idaho, was formed between 10 and 12 million years ago, and the event dropped ash to the depth of a foot 1,000 miles (1,600 km) away in northeastern Nebraska and killed a large herd of rhinoceroses, camels, and other animals at Ashfall Fossil Beds State Historical Park. Within the past 17 million years, 142 or more caldera-forming eruptions have occurred from the Yellowstone hotspot .
Yellowstone sits on top of three overlapping calderas. (USGS)
The loosely defined term 'supervolcano' has been used to describe volcanic fields that produce exceptionally big volcanic eruptions. Thus defined, the Yellowstone Supervolcano is the volcanic field which produced the latest three supereruptions from the Yellowstone hotspot. The three super eruptions occurred 2.1 million, 1.3 million, and 640,000 years ago; forming the Henry's Fork Caldera, the Island Park Caldera, and Yellowstone calderas, respectively. The Island Park Caldera supereruption (2.1 million years ago), which produced the Huckleberry Ridge Tuff, was the largest and produced 2,500 times as much ash as the 1980 Mount St. Helens eruption. The next biggest supereruption formed the Yellowstone Caldera (630,000 years ago) and produced the Lava Creek Tuff. The Henry's Fork Caldera (1.2 million years ago) produced the smaller Mesa Falls Tuff but is the only caldera from the SRP-Y hotspot that is plainly visible today.
Non-explosive eruptions of lava and less-violent explosive eruptions have occurred in and near the Yellowstone caldera since the last supereruption. The most recent lava flow occurred about 70,000 years ago, while the largest violent eruption excavated the West Thumb of Lake Yellowstone around 150,000 years ago. Smaller steam explosions occur as well; an explosion 13,800 years ago left a 5 kilometer diameter crater at Mary Bay on the edge of Yellowstone Lake (located in the center of the caldera). Currently, volcanic activity is exhibited only via numerous geothermal vents scattered throughout the region, including the famous Old Faithful Geyser.
The volcanic eruptions, as well as the continuing geothermal activity, are a result of a great cove of magma located below the caldera's surface. The magma in this cove contains gases that are kept dissolved only by the immense pressure that the magma is under. If the pressure is released to a sufficient degree by some geological shift, then some of the gases bubble out and cause the magma to expand. This can cause a runaway reaction. If the expansion results in further relief of pressure, for example, by blowing crust material off the top of the chamber, the result is a very big gas explosion.
Due to the volcanic and tectonic nature of the region, the Yellowstone Caldera experiences between 1000 and 2000 measurable earthquakes a year, though most are relatively lesser, measuring a magnitude of 3 or weaker. Occasionally, numerous earthquakes are detected shortly, an event known as an earthquake swarm. In 1985, more than 3000 earthquakes were measured over several months. More than 70 smaller swarms have been detected between 1983 and 2008. The USGS states that these swarms are caused by movements of magma and hydrothermal fluids. The most recent swarm occurred in December 2008 and continued into January 2009, with more than 500 quakes detected under the northwest end of Yellowstone Lake over a seven day span, with the largest registering a magnitude of 3.9.
The last full-scale eruption of the Yellowstone Supervolcano, the Lava Creek eruption which happened nearly 640,000 years ago, ejected approximately 240 cubic miles (1000 cubic kilometres) of rock and dust into the sky.
Geologists are closely monitoring the rise and fall of the Yellowstone Plateau, which averages ±0.6 inches (about ±1.5 cm) yearly, as an indication of changes in magma chamber pressure.
The upward movement of the Yellowstone caldera floor—almost 3 inches (7 centimeters) each year for the past three years—is more than three times greater than ever observed since such measurements began in 1923. From mid-Summer 2004 through mid-Summer 2008, the land surface within the caldera has moved upwards, as much as 8 inches at the White Lake GPS station. The U.S. Geological Survey, University of Utah and National Park Service scientists with the Yellowstone Volcano Observatory maintain that they "see no evidence that another such cataclysmic eruption will occur at Yellowstone in the foreseeable future. Recurrence intervals of these events are neither regular nor predictable.".
Studies and analysis may indicate that the greater hazard comes from hydrothermal activity which occurs independently of volcanic activity. Over 20 large craters have been produced in the past 14,000 years since the glaciers retreated from Yellowstone, resulting in such features as Mary Bay, Turbid Lake, and Indian Pond.
Lisa Morgan, a USGS researcher, explored this threat in a 2003 report, and in a recent talk postulated that an earthquake may have displaced more than 77 million cubic feet (2,200,000 m3) (576,000,000 US gallons) of water in Yellowstone Lake, creating huge waves that essentially unsealed a capped geothermal system leading into the hydrothermal explosion that formed Mary Bay.
Further research shows that earthquakes from great distances do reach and have effects upon the activities at Yellowstone, such as the 1992 7.3 magnitude Landers earthquake in California’s Mojave Desert that triggered a swarm of quakes from more than 800 miles (1,300 km) away and the Denali fault earthquake 2,000 miles (3,200 km) away in Alaska that altered the activity of many geysers and hot springs for several months afterwards.
The head of the Yellowstone Volcano Observatory, Jake Lowenstern, has proposed major upgrades and extended monitoring since the U.S. Geological Survey classified Yellowstone as a “high-threat” system
The source of the Yellowstone hotspot is controversial. Some geoscientists hypothesize that the Yellowstone hotspot is the effect of an interaction between local conditions in the lithosphere and upper mantle convection. Others prefer a deep mantle origin (mantle plume). Part of the controversy is due to the relatively sudden appearance of the hotspot in the geologic record. Additionally, the Columbia Basalt flows appeared at the same approximate time, causing speculation about their origin.
Recent Earthquakes in the Yellowstone park : Recent earthquakes for yellowstone
More from Sience daily on Yellowstone : Sience Daily
Yellowstone national park : Yellowstone
Yellowstone old faithfull Webcam
Source : Wikipedia
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Easter Island and the Moai
Easter Island (Rapa Nui: Rapa Nui), is a Polynesian island in the southeastern Pacific Ocean, at the southeastern most point of the Polynesian triangle. A special territory of Chile annexed in 1888, Easter Island is widely famous for its monumental statues, called moai , created by the Rapanui people. It is a world heritage site with much of the island protected within the Rapa Nui National Park.
The name "Easter Island" was given by the island's first recorded European visitor, the Dutch explorer Jacob Roggeveen, who encountered it on Easter Sunday 1722, while searching for Davis or David's island and named it Paasch-Eyland (18th century Dutch for "Easter Island"). The island's official Spanish name, Isla de Pascua, also means "Easter Island".
The history of Easter Island is rich and controversial. Its inhabitants have endured famines, epidemics, civil war, slave raids and colonialism, and the crash of their ecosystem; their population has declined precipitously more than once. They have left a cultural legacy that has brought them fame disproportionate to their population.
The large stone statues, or moai, for which Easter Island is world-famous, were carved during a relatively short and intense burst of creative and productive megalithic activity. A total of 887 monolithic stone statues have been inventoried on the island and in museum collections. Although often identified as "Easter Island heads", the statues are actually complete torsos, the figures kneeling on bent knees with their hands over their stomach. Some upright moai have become buried up to their necks by shifting soils.
The period when the statues were produced remains disputed, with estimates ranging from 400 CE to 1500–1700 CE. Almost all (95%) moai were carved out of distinctive, compressed, easily worked volcanic ash or tuff found at a single site inside the extinct volcano Rano Raraku. The native islanders who carved them used only stone hand chisels, mainly basalt toki, which still lie in place all over the quarry. The stone chisels were re-sharpened by chipping off a new edge when dulled. The volcanic stone the moai were carved from was first wetted to soften it before sculpting began, then again periodically during the process. While many teams worked on different statues at the same time, a single moai would take a team of five or six men approximately one year to complete. Each statue represents a deceased long-ear chief or important person.
Tukuturi, an unusual bearded kneeling moaiOnly a quarter of the statues were installed, while nearly half still remain in the quarry at Rano Raraku and the rest elsewhere on the island, probably on their way to final locations. The largest moai is known as "Paro" weighing 82 tons. There are several others close to this size. Moving the huge statues required a miro manga erua, a Y-shaped sledge with cross pieces, pulled with ropes made from the tough bark of the hau-hau tree, and tied fast around the statue's neck. Anywhere from 180 to 250 men were required for pulling, depending on the size of the moai. Some 50 of the now standing statues have been re-erected in modern times. The first moai was re-erected on the beach of Anakena in 1958 using traditional methods during an expedition to the island by Thor Heyerdahl.
The moai are monolithic statues, their minimalist style related to forms found throughout Polynesia. Moai are carved in relatively flat planes, the faces bearing proud but enigmatic expressions. The over-large heads (a three to five ratio between the head and the body, a sculptural trait which demonstrates the Polynesian belief in the sanctity of the chiefly head) have heavy brows, elongated noses with a distinctive fish-hook shaped curl of the nostrils. The lips protrude in a thin pout. Like the nose, the ears are elongated, and oblong in form. The jaw lines stand out against the truncated neck. The torsos are heavy, and sometimes the clavicles are subtly outlined in stone. The arms are carved in bas relief and rest against the body in various positions, hands and long slender fingers resting along the crests of the hips, meeting at the hami (loincloth), with the thumbs sometimes pointing towards the navel. Generally, the anatomical details of the backs are not detailed, but sometimes bear a ring and girdle motif on the buttocks and lower back. Except for one kneeling moai, the statues do not have legs.
Though moai are whole body statues, they are often described simply as "heads". This is partly because of the disproportionate size of most moai heads, and partly because from the invention of photography until the 1950s the only moai standing on the island were the statues on the slopes of Rano Raraku, many of which are buried to their shoulders. Some of the "heads" at Rano Raraku have been excavated and their bodies seen, and observed to have markings that had been protected from erosion by their burial.
All but 53 of the 887 moai known to date were carved from tuff (a compressed volcanic ash). At the end of carving they would rub the statue with pumice from Rano Raraku, where 394 moai and incomplete moai are still visible today (there are also 13 moai carved from basalt, 22 from trachyte and 17 from fragile red scoria).
Easter Island statues are known for their large, broad noses and strong chins. Along with rectangle shaped ears, deep eye slits and sometimes an upper or back ring, however most are not visible due to land over growing.
In 1979, Sergio Rapu Haoa and a team of archaeologists discovered that the hemispherical or deep elliptical eye sockets were designed to hold coral eyes with either black obsidian or red scoria pupils. The discovery was made by collecting and reassembling broken fragments of white coral that were found at the various sites. Subsequently, previously uncategorized finds in the Easter Island museum were re-examined and recategorized as eye fragments. It is thought that the moai with carved eye sockets were probably allocated to the ahu and ceremonial sites, suggesting that a selective Rapa Nui hierarchy was attributed to the moai design until its demise with the advent of the Birdman religion, Tangata Manu.
Pukao topknots and headdresses
Some moai had pukao on their heads; these were carved out of red scoria, a very light rock from a quarry at Puna Pau.
The statues were carved by the Polynesian colonizers of the island, mostly between circa 1250 CE and 1500 CE. In addition to representing deceased ancestors, the moai, once they were erected on ahu, may also have been regarded as the embodiment of powerful living or former chiefs and important lineage status symbols.
Completed statues were moved to ahu mostly on the coast, then erected, sometimes with red stone cylinders (pukao) on their heads. Moai must have been extremely expensive to craft and transport; not only would the actual carving of each statue require effort and resources, but the finished product was then hauled to its final location and erected.
The quarries in Rano Raraku appear to have been abandoned abruptly, with a litter of stone tools, many completed moai outside the quarry awaiting transport and almost as many incomplete statues still in situ as were installed on ahu. In the nineteenth century this led to conjecture that the island was the remnant of a sunken continent and that most completed moai were under the sea. That idea has long been debunked, and now it is understood that:
Some statues were rock carvings and never intended to be completed.
Some were incomplete because when inclusions were encountered the carvers would abandon a partial statue and start a new one (tuff is a soft rock with occasional lumps of much harder rock included in it).
Some completed statues at Rano Raraku were placed there permanently and not parked temporarily awaiting removal.
And some were indeed incomplete when the statue building era came to an end.
Since the island was treeless by the time the Europeans first visited, the movement of the statues was for a long time a mystery; pollen analysis has now established that the island was almost totally forested until 1200 CE. The tree pollen disappeared from the record by 1650 and the statues stopped being made around that time.
It is not known exactly how the moai were moved across the island but the process almost certainly required human energy, ropes, and possibly wooden sledges (sleds) and/or rollers; as well as leveled tracks across the island (the Easter Island roads).
Oral histories recount how various people used divine power to command the statues to walk. The earliest accounts say a king named Tuu Ku Ihu moved them with the help of the god Makemake while later stories tell of a woman who lived alone on the mountain ordering them about at her will. Scholars currently support the theory that the main method was that the moai were "walked" upright (some assume by a rocking process) as laying it prone on a sledge (the method used by the Easter Islanders to move stone in the 1860s) would have required an estimated 1500 people to move the largest moai that had been successfully erected. In 1998 Jo Anne Van Tilburg suggested less than half that number could do it by placing the sledge on lubricated rollers. In 1999 she supervised an experiment to move a 9 ton moai. They attempted to load a replica on a sledge built in the shape of an A frame which was placed on rollers. A total of 60 people pulled on several ropes in two attempts to tow the moai. The first attempt failed when the rollers jammed up. The second attempt succeeded when they embedded tracks in the ground. This was on flat ground; further experiments may be necessary to determine whether this will work on rougher terrain
In 1986, Pavel Pavel, Thor Heyerdahl and the Kon Tiki Museum experimented with a five-ton and a nine-ton moai. With a rope around the head of the statue and another around the base, using eight workers for the smaller statue and 16 for the larger, they "walked" the moai forward by swiveling and rocking it from side to side; however, the experiment was ended early due to damage to the statue bases from chipping. Despite the early end to the experiment Thor Heyerdahl estimated that this method for a 20-ton statue over Easter Island terrain would allow 320 feet (98 m) per day. Other scholars concluded that it was probably not the way the moai were moved.
Around the same time archaeologist Charles Love experimented with a 10-ton replica. His first experiment found rocking the statue to walk it was too unstable over more than a few hundred yards. He then found that placing the statue upright on two sled runners atop log rollers, 25 men were able to move the statue 150 feet (46 m) in two minutes. In 2003, further research indicated this method could explain the regularly spaced post holes where the statues were moved over rough ground. He suggested the holes contained upright posts either side of the path so that as the statue passed between them they were used as cantilevers for poles to help push the statue up a slope without the requirement of extra people pulling on the ropes and similarly to slow it on the downward slope. The poles could also act as a brake when needed.
More on the Moai Statues : Easter Island statue project
Source : Wikipedia
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The Island Socotra
Socotra or Soqotra is a small archipelago of four islands and islets in the Indian Ocean off the coast of the Horn of Africa some 190 nautical miles (220 mi; 350 km) south of the Arabian peninsula. It is so isolated that a third of its plant life is found nowhere else on the planet. It has been described as the most alien-looking place on Earth.
Socotra is part of the Republic of Yemen. It has long been a part of the 'Adan Governorate, but in 2004 it became attached to the Hadhramaut Governorate, which is much closer to the island than 'Adan (although the closest governorate would be Al Mahrah).
Socotra is one of the most isolated landforms on Earth of continental origin (i.e., not of volcanic origin). The archipelago was once part of the supercontinent of Gondwana and detached during the Miocene, in the same set of rifting events that opened the Gulf of Aden to its northwest.
The archipelago consists of the main island of Socotra (3,625 km2/Template:Convert/sq mi), the three smaller islands of Abd al Kuri, Samhah, and Darsa, and small rock outcrops like Ka’l Fir’awn and Sābūnīyah that are uninhabitable by humans but important for birds.
The main island has three geographical terrains: the narrow coastal plains, a limestone plateau permeated with karstic caves, and the Haghier Mountains. The mountains rise to 5,000 feet (1,500 m). The island is a little over 80 miles (130 km) long east to west and typically 18–22 miles (29–35 km) north to south.
The climate is generally tropical desert, with rainfall being light, seasonal (winter) and more abundant at the higher ground in the interior than along the coastal lowlands. The monsoon season brings strong winds and high seas.
Socotra is considered the "jewel" of biodiversity in the Arabian sea. The long geological isolation of the Socotra archipelago and its fierce heat and drought have combined to create a unique and spectacular endemic flora (which may, therefore, be vulnerable to introduced species such as goats). Surveys have revealed that more than a third of the 800 or so plant species of Socotra are found nowhere else. Botanists rank the flora of Socotra among the ten most endangered island flora in the world. The archipelago is a site of global importance for biodiversity conservation and a possible center for ecotourism.
One of the most striking of Socotra's plants is the dragon's blood tree (Dracaena cinnabari), which is a strange-looking, umbrella-shaped tree. Its red sap was the dragon's blood of the ancients, sought after as a medicine and a dye. Another unusual plant is Dorstenia gigas.
The island group also has a fairly rich bird fauna, including a few types of endemic birds, such as the Socotra Starling Onychognathus frater, the Socotra Sunbird Nectarinia balfouri, Socotra Sparrow Passer insularis and Socotra Grosbeak Rhynchostruthus socotranus.
As with many isolated island systems, bats are the only mammals native to Socotra. In contrast, the marine biodiversity around Socotra is rich, characterized by a unique mixture of species that have originated in farflung biogeographic regions: the western Indian Ocean, the Red Sea, Arabia, East Africa and the wider Indo-Pacific.
The island was recognised by the United Nations Educational, Scientific and Cultural Organization (UNESCO) as a world natural heritage site in July 2008. The European Union has supported such a move, calling on both UNESCO and International Organization of Protecting Environment to classify the island archipelago among the environmental heritages.
The inhabitants are of Arab, Somali & South Asian origins. They follow the Islamic faith, and speak Soqotri, a Semitic language. Their primary occupation has been fishing, livestock rearing and date cultivation.Almost all inhabitants of Socotra, numbered at 50,000, live on the main island. The principal city is Hadiboh (population 8,545 at the census of 2004). The second largest town is Qulansiyah, with a population of 3,862, followed by Qād̨ub, population 929. Those three main towns are all located on the north coast. 'Abd-al-Kūrī and Samha have a population of a few hundred people between them; Darsa and the remaining islands are uninhabited.
Socotra appears as Dioskouridou ("of the Dioscurides") in the Periplus of the Erythraean Sea, a 1st century A.D. Greek navigation aid. In the notes to his translation of the Periplus, G.W.B. Huntingford remarks that the name Socotra is not Greek in origin, but derives from the Sanskrit dvipa sukhadhara ("island of bliss").
A local tradition holds that the inhabitants were converted to Christianity by Thomas in AD 52. In the 10th century the Arab geographer Abu Mohammed Al-Hassan Al-Hamdani stated that in his time most of the inhabitants were Christians. Socotra is also mentioned in The Travels of Marco Polo according to which "the inhabitants are baptized Christians and have an archbishop" who, it is further explained, "has nothing to do with the Pope at Rome, but is subject to an archbishop who lives at Baghdad". They were Nestorians (Nestorianism is the doctrine that the two individual natures of Christ, the human and the divine, are joined in conjunction ("synapheia") rather than in hypostatic union) but they also practiced ancient magic rituals despite the warnings of their archbishop.
More on the island Socotra : To visit Socotra
Source : Wikipedia
The island Socotra
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The Great Blue hole - Belize
The Great Blue Hole is a large underwater sinkhole off the coast of Belize. It lies near the center of Lighthouse Reef, a small atoll 100 kilometres (62 mi) from the mainland and Belize City. The hole is circular in shape, over 300 metres (984 ft) across and 125 metres (410 ft) deep. It was formed as a limestone cave system during the last glacial period when sea levels were much lower. As the ocean began to rise again, the caves flooded, and the roof collapsed. Believed to be the world’s largest feature of its kind, the Great Blue Hole is part of the larger Belize Barrier Reef Reserve System, a World Heritage site of the United Nations Educational, Scientific and Cultural Organization (UNESCO).
This site was made famous by Jacques-Yves Cousteau who declared it one of the top ten scuba diving sites in the world. In 1971, he brought his ship, the Calypso, to the hole to chart its depths. Investigations by this expedition confirmed the hole's origin as typical karst limestone formations, formed before rises in sea level in at least four stages, leaving ledges at depths of 21, 49 and 91 meters (69, 161 and 299 ft). Stalactites were retrieved from submerged caves, confirming their previous formation above sea level. Some of these stalactites were also off-vertical by 10°-13° in a consistent orientation, thus indicating that there had also been some past geological shift and tilting of the underlying plateau, followed by a long period in the current plane.
This is a popular spot amongst recreational scuba divers, who are lured by the opportunity to dive in crystal clear water and meet several species of fish, including giant groupers, nurse sharks and several types of reef sharks such as the Caribbean reef shark and the Blacktip shark. Other species of sharks, like the bull shark and hammerheads, have been reported there, but are not regular sightings. Usually, dive trips to the Great Blue Hole are full-day trips, which include one dive in the Blue Hole and two further dives in nearby reefs.
On-shore caves of similar formation, as large collapsed sinkholes, are well known in Belize, and in the Yucatan Peninsula, where they are known as "cenotes".
More on the blue holes : dailyscubadiving
Source : Wikipedia
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