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52-598: Mizda or Mesdah (Tamazight: ⵎⵉⵣⴷⴰ, Mizda ) is a town in the Nafusa Mountains in Libya . It was the capital of the former Mizda District . Just to the west of Mizda is the Mizda Army Base at 31°25′29″N 12°56′54″E  /  31.42472°N 12.94833°E  / 31.42472; 12.94833 The Berber tribe Awlad Abu Say is centered around Mizda and Gharyan to the north. This Libya location article

104-452: A topographic map . However, when the key col is far away, or when one wants to calculate the prominence of many peaks at once, software can apply surface network modeling to a digital elevation model to find exact or approximate key cols. Since topographic maps typically show elevation using contour lines , the exact elevation is typically bounded by an upper and lower contour, and not specified exactly. Prominence calculations may use

156-420: A "closer" peak than the encirclement parent (if there is one), which is still "better" than the peak in question. The differences lie in what criteria are used to define "closer" and "better." The (prominence) parent peak of peak A can be found by dividing the island or region in question into territories, by tracing the two hydrographic runoffs, one in each direction, downwards from the key col of every peak that

208-489: A "hierarchy" of peaks going back to the highest point on the island. One such chain in Britain would read: Billinge Hill → Winter Hill → Hail Storm Hill → Boulsworth Hill → Kinder Scout → Cross Fell → Helvellyn → Scafell Pike → Snowdon → Ben Nevis . At each stage in the chain, both height and prominence increase. Line parentage, also called height parentage, is similar to prominence parentage, but it requires

260-514: A distance of 360 m (1200 feet). The key col may also be close to the subject peak or far from it. The key col for Aconcagua, if sea level is disregarded, is the Bering Strait at a distance of 13,655 km (8,485 miles). The key col for the South Summit of Mount Everest is about 100 m (330 feet) distant. A way to visualize prominence is to imagine raising sea level so

312-574: A fighting force. Under the leadership of Imam Abu al-Khattab al-Ma'afari, the Nafusa descended from the mountains and proceeded to conquer all of the crumbling Fihrid emirate of Ifriqiya - capturing Tripoli in 757 and Kairouan in 758. But the Abbasid Arab governor of Egypt invaded Ifriqya, defeated the Nafusa in a battle at Tawergha in 761 (his third attempt - his first two armies had been repulsed) and put an end to their putative new state. However,

364-492: A given peak in the following manner: for every path connecting the peak to higher terrain, find the lowest point on the path; the key col (or highest saddle , or linking col , or link ) is defined as the highest of these points, along all connecting paths; the prominence is the difference between the elevation of the peak and the elevation of its key col. On a given landmass, the highest peak's prominence will be identical to its elevation. An alternative equivalent definition

416-408: A great deal of information about the peak's position. In general, the analysis of parents and lineages is intimately linked to studying the topology of watersheds . Alteration of the landscape by humans and presence of water features can give rise to issues in the choice of location and height of a summit or col. In Britain, extensive discussion has resulted in a protocol that has been adopted by

468-479: A hierarchy which defines some peaks as subpeaks of others. For example, in Figure ;1, the middle peak is a subpeak of the right peak, which is a subpeak of the left peak, which is the highest point on its landmass. In that example, there is no controversy about the hierarchy; in practice, there are different definitions of parent. These different definitions follow. Also known as prominence island parentage , this

520-418: A highest submerged col of about 40 m, or only 8888 m below the peak of Everest. As a result, Mauna Kea's prominence might be subjectively more impressive than Everest's, and some authorities have called it the tallest mountain from peak to underwater base. Dry prominence is also useful for measuring submerged seamounts . Seamounts have a dry topographic prominence, a topographic isolation , and

572-543: A hotbed for anti-Gaddafi protests (with protests breaking out relatively early in Nalut and Zintan) and then a rebel stronghold, an island of rebel control in the mainly Gaddafi-controlled western part of the country. During the early stages, forces allied to the national transitional government succeeded in evacuating most non-combatants into Tunisia; the Wazzin border crossing was captured and held to ensure supply lines from Tunisia; all

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624-409: A prominence cutoff criterion. The height parent is the closest peak to peak A (along all ridges connected to A) that has a greater height than A, and satisfies some prominence criteria. The disadvantage of this concept is that it goes against the intuition that a parent peak should always be more significant than its child. However it can be used to build an entire lineage for a peak which contains

676-437: A prominence-ranked list is that it needs no cutoff since a peak with high prominence is automatically an independent peak. It is common to define a peak's parent as a particular peak in the higher terrain connected to the peak by the key col. If there are many higher peaks there are various ways of defining which one is the parent, not necessarily based on geological or geomorphological factors. The "parent" relationship defines

728-606: A team in Zintan to help the large number of wounded. Al Galaa was without electricity and water for seven weeks, and more than 45,000 refugees fled for safety to the adjoining Tunisian region of Tatouine , where many had relatives. As towns and villages in the Nafusa Mountains and surrounding areas were liberated from control by forces loyal to Muammar Gaddafi in early summer 2011, and while fierce fighting continued, Berber exhibitions and workshops sprang up to share and spread

780-479: Is Aconcagua (6,960 m), in Argentina , and its prominence is 6,138 m. (To further illustrate the rising-sea model of prominence, if sea level rose 56 m, North and South America would be separate continents and Denali would be 6138 m, its current prominence, above sea level. At a slightly lower level, the continents would still be connected and the high point of the combined landmass would be Aconcagua,

832-517: Is a stub . You can help Misplaced Pages by expanding it . Nafusa Mountains The area was a major population and cultural center of the Libu , who repeatedly expanded west. In the aftermath of the great Berber Revolt of the 8th century, Ibadi missionaries that had fled from the Umayyad Caliphate took refuge in the Nafusa Mountains. Preachers converted and organized the native Nafusa people into

884-452: Is a sub-summit of the main summit (which has a height and prominence of 8,848 m). Many lists of mountains use topographic prominence as a criterion for inclusion in the list, or cutoff . John and Anne Nuttall's The Mountains of England and Wales uses a cutoff of 15 m (about 50 ft), and Alan Dawson's list of Marilyns uses 150 m (about 500 ft). (Dawson's list and the term "Marilyn" are limited to Britain and Ireland). In

936-443: Is becoming preferred. There are two varieties of topographic prominence: wet prominence and dry prominence. Wet prominence is the standard topographic prominence discussed in this article. Wet prominence assumes that the surface of the earth includes all permanent water, snow, and ice features. Thus, the wet prominence of the highest summit of an ocean island or landmass is always equal to the summit's elevation. Dry prominence, on

988-406: Is defined as follows. In Figure 2 the key col of peak A is at the meeting place of two closed contours, one encircling A (and no higher peaks) and the other containing at least one higher peak. The encirclement parent of A is the highest peak that is inside this other contour. In terms of the falling-sea model, the two contours together bound an "island", with two pieces connected by an isthmus at

1040-404: Is equal to its wet prominence (4205 m) plus the depth of its highest submerged col (about 5125 m). Totaling 9330 m, this is greater than any mountain apart from Everest. The dry prominence of Aconcagua is equal to its wet prominence (6960 m) plus the depth of the highest submerged col of the Bering Strait (about 40 m), or about 7000 m. It is worth noting Mauna Kea

1092-553: Is equal to its wet prominence plus the depth of its highest submerged col. Because Earth has no higher summit than Mount Everest , Everest's prominence is either undefined or its height from the lowest contour line. In a dry Earth, the lowest contour line would be the deepest hydrologic feature, the Challenger Deep , at 10,924 m depth. Everest's dry prominence would be this depth plus Everest's wet prominence of 8848 m, totaling 19,772 m. The dry prominence of Mauna Kea

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1144-406: Is more prominent than peak A. The parent is the peak whose territory peak A is in. For hills with low prominence in Britain, a definition of "parent Marilyn " is sometimes used to classify low hills ("Marilyn" being a British term for a hill with a prominence of at least 150 m). This is found by dividing the region of Britain in question into territories, one for each Marilyn . The parent Marilyn

1196-457: Is not used because there is no obvious choice of cutoff. This choice of method might at first seem arbitrary, but it provides every hill with a clear and unambiguous parent peak that is taller and more prominent than the hill itself, while also being connected to it (via ridge lines). The parent of a low hill will also usually be nearby; this becomes less likely as the hill's height and prominence increase. Using prominence parentage, one may produce

1248-503: Is rather flat apart from the effects of differential erosion. Towns in the mountains include Gharyan , Yafran , Zintan , Qotros , Jadu , Kabaw , Al-Qawalish and Nalut , which have all been the sites of military action during the 2011 civil war. Since 2007, the mountains stretch across two districts: Jabal al Gharbi District and Nalut District . The mountain villages raise primarily goats, olives and grain, but also have fig and apricot orchards. The Nafusa Mountains became first

1300-572: Is relatively close to its submerged key col in the Pacific Ocean, and the corresponding contour line that surrounds Mauna Kea is a relatively compact area of the ocean floor. Whereas a contour line around Everest that is lower than 9330m from Everest's peak would surround most of the major continents of the Earth. Even just surrounding Afro-Eurasia would run a contour line through the Bering Straight, with

1352-535: Is that the prominence is the height of the peak's summit above the lowest contour line encircling it, but containing no higher summit within it; see Figure 1. The parent peak may be either close or far from the subject peak. The summit of Mount Everest is the parent peak of Aconcagua in Argentina at a distance of 17,755 km (11,032 miles), as well as the parent of the South Summit of Mount Everest at

1404-677: Is the Marilyn whose territory the hill's summit is in. If the hill is on an island (in Britain) whose highest point is less than 150 m, it has no parent Marilyn. Prominence parentage is the only definition used in the British Isles because encirclement parentage breaks down when the key col approaches sea level. Using the encirclement definition, the parent of almost any small hill in a low-lying coastal area would be Ben Nevis , an unhelpful and confusing outcome. Meanwhile, "height" parentage (see below)

1456-561: The Tamazight culture and language, after four decades during which there were severe punishments for speaking and writing Tamazight openly. Topographic prominence In topography , prominence or relative height (also referred to as autonomous height , and shoulder drop in US English, and drop in British English) measures the height of a mountain or hill's summit relative to

1508-705: The Nafusa mountains themselves remained unconquered. Throughout the 9th century, while the Aghlabids ruled in Ifriqiya, the Ibadi maintained an independent puritan republic in the Nafusa mountains. The Imamate of Nafusa was in close alliance with the other Ibadi remnant, the Rustamid dynasty in Tiaret , both constant thorns on either side of the Aghlabids, in communication with each other across

1560-482: The Nafusa prisoners and put an end to their independent imamate (Tahert fell shortly after, in 911). Despite the destruction of their states, Ibadi Islam remained a strong (if clandestine) faith among the Berbers of the Nafusa mountains for centuries after, down to the modern day. The lingering heterodoxy of the Nafusa people has placed them frequently at odds, or under suspicion, by the largely orthodox Sunni population of

1612-629: The advantage of high ground. By the end of June 2011 the Nafusi people had almost succeeded in liberating themselves completely from the control of the regime. The Nafusa Mountains form the boundary between the Libyan coastal plain, known as the Jafara, to the north, and the Tripolitanian Plateau to the south. The beds (strata) of the Tripolitanian Plateau slope downwards to the south and tilt upwards towards

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1664-591: The back highlands of North Africa. In 879, the Tulunids of Egypt invaded Aghlabid Ifriqya and captured Tripoli. But the Nafusa challenged and destroyed the Egyptian army in 880. Again the Nafusa victory was short-lived. In 896-97, the Aghlabid emir Ibrahim II of Ifriqiya recovered Tripolitana and defeated the Nafusa in a great battle at Manu (south of Gabès ). In the aftermath, citing them as heretics, Ibrahim II executed all

1716-408: The child peak. For example, one common use of the concept of parent is to make clear the location of a peak. If we say that Peak A has Mont Blanc for a parent, we would expect to find Peak A somewhere close to Mont Blanc. This is not always the case for the various concepts of parent, and is least likely to be the case for encirclement parentage. Figure 3 shows a schematic range of peaks with

1768-572: The city of Gharyan (about 60 km (40 mi) south of Tripoli) in the east to the city of Wazzin at the Tunisian border in the west. Spurs and isolated upthrusts continue into Tunisia, but this region is almost unpopulated, in marked contrast to the situation in Libya. The mountain area is rarely more than 25 km (16 mi) in depth, from its southern boundary, the flat arid plateau some 650 m (2,100 ft) above sea level, to its northern limit on

1820-410: The color underlying the minor peaks indicating the encirclement parent. In this case the encirclement parent of M is H whereas an intuitive view might be that L was the parent. Indeed, if col "k" were slightly lower, L would be the true encirclement parent. The encirclement parent is the highest possible parent for a peak; all other definitions indicate a (possibly different) peak on the combined island,

1872-400: The contiguous United States, the famous list of " fourteeners " (14,000 foot / 4268 m peaks) uses a cutoff of 300 ft / 91 m (with some exceptions). Also in the U.S., 2000 ft (610 m) of prominence has become an informal threshold that signifies that a peak has major stature. Lists with a high topographic prominence cutoff tend to favor isolated peaks or those that are

1924-482: The disadvantage in using the encirclement parent. A hill in a low-lying area like the Netherlands will often be a direct child of Mount Everest , with its prominence about the same as its height and its key col placed at or near the foot of the hill, well below, for instance, the 113-meter-high key col of Mont Blanc . When the key col for a peak is close to the peak itself, prominence is easily computed by hand using

1976-475: The encirclement parent.) While it is natural for Aconcagua to be the parent of Denali, since Denali is a major peak, consider the following situation: Peak A is a small hill on the coast of Alaska, with elevation 100 m and key col 50 m. Then the encirclement parent of Peak A is also Aconcagua, even though there will be many peaks closer to Peak A which are much higher and more prominent than Peak A (for example, Denali). This illustrates

2028-489: The high contour (giving in a pessimistic estimate ), the low contour (giving an optimistic estimate), their mean (giving a "midrange" or "rise" prominence ) or an interpolated value (customary in Britain). The choice of method depends largely on the preference of the author and historical precedent. Pessimistic prominence, (and sometimes optimistic prominence) were for many years used in USA and international lists, but mean prominence

2080-662: The highest point of their massif ; a low value, such as the Nuttalls', results in a list with many summits that may be viewed by some as insignificant. While the use of prominence as a cutoff to form a list of peaks ranked by elevation is standard and is the most common use of the concept, it is also possible to use prominence as a mountain measure in itself. This generates lists of peaks ranked by prominence , which are qualitatively different from lists ranked by elevation. Such lists tend to emphasize isolated high peaks, such as range or island high points and stratovolcanoes . One advantage of

2132-424: The highest points around and are likely to have extraordinary views. Only summits with a sufficient degree of prominence are regarded as independent mountains. For example, the world's second-highest mountain is K2 (height 8,611 m, prominence 4,017 m). While Mount Everest 's South Summit (height 8,749 m, prominence 11 m ) is taller than K2, it is not considered an independent mountain because it

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2184-495: The key col. The encirclement parent is the highest point on this entire island. For example, the encirclement parent of Mont Blanc , the highest peak in the Alps , is Mount Everest . Mont Blanc's key col is a piece of low ground near Lake Onega in northwestern Russia (at 113 m (371 ft) elevation), on the divide between lands draining into the Baltic and Caspian Seas . This is

2236-447: The lowest contour line encircling it but containing no higher summit within it. It is a measure of the independence of a summit . The key col ("saddle") around the peak is a unique point on this contour line and the parent peak is some higher mountain, selected according to various criteria. The prominence of a peak is the least drop in height necessary in order to get from the summit to any higher terrain. This can be calculated for

2288-435: The main sources of prominence data in Britain and Ireland. Other sources of data commonly ignore human-made alterations, but this convention is not universally agreed upon; for example, some authors discount modern structures but allow ancient ones. Another disagreement concerns mountaintop removal , though for high-prominence peaks (and for low-prominence subpeaks with intact summits), the difference in prominence values for

2340-420: The meeting place of two 113 m (371 ft) contours, one of them encircling Mont Blanc; the other contour encircles Mount Everest. This example demonstrates that the encirclement parent can be very far away from the peak in question when the key col is low. This means that, while simple to define, the encirclement parent often does not satisfy the intuitive requirement that the parent peak should be close to

2392-471: The mountain towns were retaken; and the front extended to the plains, cutting regime communications lines and allowing electricity to be restored. They were the first rebel combatants to be supplied with arms by air-drop. In the course of the civil war, many towns in the area were subjected to shelling by artillery and rockets from both sides, with much damage to infrastructure. Regime forces cut off electricity and water supplies. Médecins Sans Frontières sent

2444-467: The north creating the highest portion of the plateau as the Nafusa mountains which rise to over 750 m (2,500 ft). The plateau ends abruptly on the north with an escarpment which has up to 350 m (1,100 ft) of topographic prominence. A series of deep valleys which drain north toward the Jefara cut into this escarpment. It extends about 250 km (160 mi) within Libya, from just east of

2496-402: The other hand, ignores water, snow, and ice features and assumes that the surface of the earth is defined by the solid bottom of those features. The dry prominence of a summit is equal to its wet prominence unless the summit is the highest point of a landmass or island, or its key col is covered by snow or ice. If its highest surface col is on water, snow, or ice, the dry prominence of that summit

2548-569: The parent peak and subject peak are two separate islands. Then lower it until a tiny land bridge forms between the two islands. This land bridge is the key col of the subject peak, and the peak's prominence is its elevation from that key col. Prominence is interesting to many mountaineers because it is an objective measurement that is strongly correlated with the subjective significance of a summit. Peaks with low prominence are either subsidiary tops of some higher summit or relatively insignificant independent summits. Peaks with high prominence tend to be

2600-425: The plain, where the land falls to below 150 m (490 ft). Much of the 500 m (2,000 ft) drop in level is accomplished abruptly, at the escarpment, where local topographic prominences may be up to 350 m (1,100 ft). It is from below, on the plain, viewing the steep slopes and sharply-etched skyline that the area appears mountainous; from the plateau the land appears merely hilly, and in fact it

2652-518: The rest of Libya. This distinct culture, suppressed and oppressed by the Libyan regime, has risen to new prominence in the course of the Libyan Civil War (2011) , when their initiatives led to the Nafusa Mountains becoming a major front in that war. The terrain and topography of the region are critical strategic factors, constraining mechanised advances from the flat plain and plateau, and favouring guerrilla tactics based on close local knowledge and

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2704-497: The two conventions is typically relatively small. The key col and parent peak are often close to the sub-peak but this is not always the case, especially when the key col is relatively low. It is only with the advent of computer programs and geographical databases that thorough analysis has become possible . For example, the key col of Denali in Alaska (6,194 m) is a 56 m col near Lake Nicaragua . Denali's encirclement parent

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