Soil erosion is often considered to be the primary cause of land and mountain loss on islands, but new research has found that on Oahu the mountains are being dissolved and destroyed by groundwater. 
 
 Eventually the mountains Koolau and Waianae on Oahu will be dissolved until the island becomes a nearly flat, very low-lying island similar to Midway. 
 
 “We tried to figure out how fast the island is going away and what the influence of climate is on that rate,” said Brigham Young University geologist Steve Nelson. “More material is dissolving from those islands than what is being carried off through erosion.” 
 
 
 
 
 
 The research was done by comparing the effects of groundwater compared to stream water, to find out which one was removing more mineral material. “Nelson and his BYU colleagues spent two months sampling both types of sources. In addition, ground and surface water estimates from the U.S. Geological Survey helped them calculate the total quantity of mass that disappeared from the island each year.” 
 
 “All of the Hawaiian Islands are made of just one kind of rock,” Nelson said. “The weathering rates are variable, too, because rainfall is so variable, so it’s a great natural laboratory.” 
 
 In order to get an idea of what will happen to the island in the future it was also necessary to take into account plate tectonics. As Oahu is being forced northwest, it actually rises in elevation slowly. 
 
 “According to the researchers’ estimates, the net effect is that Oahu will continue to grow for as long as 1.5 million years. Beyond that, the force of groundwater will eventually triumph and the island will begin its descent to a low-lying topography.” 
 
 The researchers got something of a surprise when they were doing their mineralogical analysis of the soil samples that they took. 
 
 “The main thing that surprised me on the way was the appearance of a large amount of quartz in a saprolite taken from a 1-meter depth,” Brian Selck, co-author of the study, said. 
 
 The research was just published in the journal Geochimica et Cosmochimica Acta. 
 
 Source: Brigham Young University 
 
 Image Credits: Brigham Young University ||||| PROVO, Utah, Dec. 21 (UPI) -- The mountains on Oahu in the Hawaiian Islands are dissolving from within under the slow but inexorable onslaught of groundwater, researchers say. 
 
 Sometime in the distant future the mountainous tropical island will be reduced to a flat, low-lying island similar to Midway, scientists at Brigham Young University reported Friday. 
 
 While external erosion is the primary force that wears down mountains, that's not the case on Oahu, they said. 
 
 "We tried to figure out how fast the island is going away and what the influence of climate is on that rate," BYU geologist Steve Nelson said. "More material is dissolving from those islands than what is being carried off through erosion." 
 
 That was the result from comparing groundwater against stream water to see which removed more of the total quantity of mineral material mass that disappeared from the island each year, the researchers said. 
 
 "All of the Hawaiian Islands are made of just one kind of rock," Nelson said, referring to the volcanic composition of the islands. "The weathering rates are variable, too, because rainfall is so variable, so it's a great natural laboratory." 
 
 While Oahu is at present still growing, after about 1.5 million years the force of groundwater will eventually triumph and the island will begin its descent to a low-lying topography, the researchers said. ||||| Bibliographic Entry Result 
 
 (w/surrounding text) Standardized 
 
 Result Information Central. National Geographic. 9 June 2001. "Mountains are generally measured from sea level, in which case Mount Everest (29,028 feet; 8,848 meters) is king." 8,848 m 
 
 (Everest) "Hawaii's Mauna Kea, though, rises an astonishing 33,476 feet (10,203 meters) from the depths of the Pacific Ocean floor. Measuring from base to peak, Mauna Kea is the tallest mountain on earth." 10,203 m 
 
 (Mauna Kea) "A third way to determine the world's highest mountain is to measure the distance from the center of the earth to the peak. Using this method, Chimborazo in the Andes triumphs. Although it stands but 20,561 feet (6,267 meters) above sea level, its peak is the farthest from the earth's center." 6,267 m 
 
 (Chimborazo) "Mount Everest." World Book. 2001 ed. Vol. 5-E: 519. "The official height of Mount Everest is 29,035 feet (8,850 meters)." 8,850 m 
 
 (Everest) "Mauna Kea." World Book. 2001 ed. Vol. 13-M: 884. "Rising about 33, 500 feet (10,200 meters) from the Pacific Floor, it is the world's highest mountain island." 10,200 m 
 
 (Mauna Kea) "Chimborazo." World Book. 2001 ed. Vol. 3-C-Ch: 471. "Mount Chimborazo rises 20,561 feet (6,267 meters) above sea level." 6,267 m 
 
 (Chimborazo) Egbert, Jean L. Facts. The Ocean Frontier. Flamingo Communications. 1999-2001. "If you say that "tallest" means the greatest distance above sea level, that would be the mountain you expect, Mt. Everest, at 8,848 meters above sea level." 8,848 m 
 
 (Everest) "And if you define "tallest" as the distance between the base and the top of a mountain, you get yet a third tallest mountain, most of which is under the sea: Mauna Kea, in Hawaii. It's 10,204 meters from its base on the sea floor to its tip." 10,204 m 
 
 (Mauna Kea) "But if you define "tallest" as the farthest distance from the center of the Earth, that would be Mt. Chimborazo, in Equador [sic], at 6,267 meters above sea level …. [I[t's farther away from Earth's center, at 6,384,404 meters; Mt. Everest is 6,381,670 meters from the center of the Earth." 6,267 m 
 
 (Chimborazo) Past GeoFacts. US Geological Survey, Pasadena. "It is well known that the HIGHEST mountain on earth is Mt. Everest on the Nepal-Tibet border in the Himalayas. It stands 8,848 m (29,028 ft) above sea level." 8,848 m 
 
 (Everest) "The TALLEST mountain on earth, measured from base to summit is the volcanic peak of Mauna Kea, one of five volcanic masses making up the "Big Island"of Hawaii. It is about 9,000 m (30,000 ft) tall, however only 4,245 m (13,796 ft) of that is above sea level." 9,000 m 
 
 (Mauna Kea) "The point FARTHEST FROM THE center OF THE EARTH is the summit of Chimborazo volcano in the Andes of Ecuador. Its elevation is only 6,310 m (20,703 ft) but because of its location near the equator it gets a boost from the equatorial bulge caused by the spin of the earth. This bulge makes the earth's radius about 21,000 m (68,900 ft) greater at the equator than at the poles. In fact, the beaches of Ecuador are farther from the center of the earth than is the summit of Mt. Everest." 6,310 m 
 
 (Chimborazo) 
 
 A mountain is an elevation in the earth's surface. The elevation, or altitude, of a mountain is given as the height of the summit above sea level. Mountains are much bigger than hills. Most of the time they are made up elongated ranges. It is rare when a mountain stands alone. 
 
 What is the difference between tallest and highest? Tallest: the top is the furthest away from the base. Highest: the top is the furthest away from sea level. There are three ways of measuring the height of a mountain. So which mountain is the tallest? One way to measure a mountain is by measuring from sea level. The second way is by measuring from base to peak. The third way is by measuring the distance from the center of the earth to the peak of the mountain. 
 
 Mt. Everest, on the Nepal-Tibet border in the Himalayas, is the highest mountain on earth. It is about 8,850 meters above sea level. height was confirmed in December 1983 during a surveillance mission by the space shuttle Columbia. Mauna Kea, or "White Mountain"a volcano of the "Big Island" of Hawaii, is the tallest mountain on earth. It measure about 10,200 meters from base to summit. Chimborazo is a volcano in the Andes of Ecuador. It measures about 6,310 meters above sea level. When height is measured from the center of the earth, Chimborazo is tallest since it is located nearly on the equator, where the earth bulges the most. 
 
 Beata Unke -- 2001 
 
 Bibliographic Entry Result 
 
 (w/surrounding text) Standardized 
 
 Result Technology Lifts Everest to New Official Height. National Geographic Society. 11 November 1999. "The revised elevation -- 29,035 feet (8,850 meters) -- was announced November 11, 1999 by Bradford Washburn, renowned mountain photographer/explorer and honorary director of Boston's Museum of Science, at the opening reception of the 87th annual meeting of the American Alpine Club." 8,850 m 
 
 (Everest) 
 
 The value above is now recognized as the most accurate measurement of the altitude of Mount Everest. 
 
 Bibliographic Entry Result 
 
 (w/surrounding text) Standardized 
 
 Result Geography of Guam. Official Guam Website. "The highest point is Mount Lamlam with an elevation of 1,334 feet. The Peak of a submerged mountain, Guam, rises 37,820 feet above the floor of the Marianas Trench, the greatest ocean depth in the world." 11,530 m 
 
 (Lamlam) National Geographic Atlas of the World. Sixth Edition. Washington, DC: National Geographic Society, 1999. [Pacific Ocean Floor: page 105] 
 
 "Challenger Deep, -10924 (-35839 ft), World's Greatest Ocean Depth" 11,330 m 
 
 (Lamlam) [Islands of the Pacific: page 111] 
 
 "Mount Lamlam 406" [Pacific Ocean Floor: page 105] 
 
 "West Mariana Basin, 4885 
 
 East Mariana Basin, 5984" 5,300 m 
 
 (Lamlam) 
 
 The island of Guam is a territory of the United States lying in the western Pacific. Guam is the southernmost island in the Mariana chain. These islands lie on a subduction zone — a region where one tectonic plate (the heavier Pacific plate) is driven under another (the lighter Philippine plate). Subduction results in an oceanic trench trench forming on one side and a mountain range forming on the other. The mountain range formed at the Mariana subduction zone is not that impressive. The second tallest peak is Mount Lamlam on the island of Guam at 406 m. (The tallest peak is Ogso Tagpochau on Saipan at 465 m.) The mountains may not be that impressive, but the trench certainly is. The Challenger Deep on the Mariana Trench is the deepest point on the earth — 10,924 m below sea level. If we take the bottom of Challenger Deep as the base of Mount Lamlam it suddenly becomes the tallest mountain on earth. 
 
 406 m + 10,924 m = 11,330 m 
 
 Or so they say. 
 
 The Mariana Islands lie on a chain running from Farallon de Pajaros in the north to Guam in the south. The Mariana Trench lies to the east of the islands paralleling the chain until it reaches Guam where it makes a right angle turn and heads west. The Challenger Deep is about 400 km southwest of Guam on this perpendicular segment in a region known as the Southern Arc. Four hundred kilometers may not seem very far in oceanic terms, but lying in this gap are about a dozen underwater peaks adjacent to the Southern Arc. These submerged peaks are really the "mountains" lying next to the Challenger Deep. 
 
 
 
 Source: University of Hawaii 
 
 We have a real problem now. If we measure Mount Lamlam from the deepest point in the Mariana Trench adjacent to Guam, it is no longer taller than Mauna Kea (although it's probably still taller than Mount Everest). And if we measure the highest of the underwater peaks adjacent to the Challenger Deep from its deepest point we still don't beat Mauna Kea. 
 
 I would take this claim even further to task. There is no trench on the western edge of Guam, just a moderately deep basin (the appropriately named West Mariana Basin) with a maximum depth of 4885 m. Similarly, looking east beyond the trench we find a slightly deeper basin (the appropriately named East Mariana Basin) with a maximum depth of 5984 m. A profile through this region of the sea floor would look like a serpentine curve: initially flat but rising ever quicker to a narrow peak then rapidly dropping to a narrow trench that rises just as quickly back to flat again. If we take these basins as the "true" base of both Mount Lamlam and Challenger Deep respectively, a more accurate picture emerges. Mount Lamlam is roughly 5300 m tall from its western base to its peak and Challenger Deep is roughly 4900 m from its eastern base to its depths. 
 
 Mount Lamlam is tall, but certainly not the tallest mountain measured from base to peak. 
 
 Editor's Supplement -- 2003 
 
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– Hawaii's island of Oahu is renowned for its mountainous vistas, but someday it's going to be flat as a pancake, or at least as flat as Midway. So say researchers from Brigham Young University in a new study, reports UPI. The big factor isn't what you might expect, namely external erosion. Rather, the island's own groundwater is slowly dissolving the mountains. The weird part, explains PlanetSave, is that Oahu's elevation is actually going to keep growing for 1.5 million years because of how it's being shifted by tectonic plates. But after that, the slow descent begins.