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39-557: It is also among the largest huts of the massif , together with the Monte Rosa Hut and Gnifetti Hut . The Margherita Hut is located in Italian territory, near the international border between Italy and Switzerland , in the Italian region of Piedmont . The nearest settlement is Alagna Valsesia , in Piedmont, starting point for the traditional climb to the hut. The construction of the hut

78-405: A decollement . Extensional decollements can grow to great dimensions and form detachment faults , which are low-angle normal faults with regional tectonic significance. Due to the curvature of the fault plane, the horizontal extensional displacement on a listric fault implies a geometric "gap" between the hanging and footwalls of the fault forms when the slip motion occurs. To accommodate into

117-829: A plate boundary. This class is related to an offset in a spreading center , such as a mid-ocean ridge , or, less common, within continental lithosphere , such as the Dead Sea Transform in the Middle East or the Alpine Fault in New Zealand. Transform faults are also referred to as "conservative" plate boundaries since the lithosphere is neither created nor destroyed. Dip-slip faults can be either normal (" extensional ") or reverse . The terminology of "normal" and "reverse" comes from coal mining in England, where normal faults are

156-574: A fault hosting valuable porphyry copper deposits is northern Chile's Domeyko Fault with deposits at Chuquicamata , Collahuasi , El Abra , El Salvador , La Escondida and Potrerillos . Further south in Chile Los Bronces and El Teniente porphyry copper deposit lie each at the intersection of two fault systems. Faults may not always act as conduits to surface. It has been proposed that deep-seated "misoriented" faults may instead be zones where magmas forming porphyry copper stagnate achieving

195-500: A fault is locked, and when it reaches a level that exceeds the strength threshold, the fault ruptures and the accumulated strain energy is released in part as seismic waves , forming an earthquake . Strain occurs accumulatively or instantaneously, depending on the liquid state of the rock; the ductile lower crust and mantle accumulate deformation gradually via shearing , whereas the brittle upper crust reacts by fracture – instantaneous stress release – resulting in motion along

234-410: A fault often forms a discontinuity that may have a large influence on the mechanical behavior (strength, deformation, etc.) of soil and rock masses in, for example, tunnel , foundation , or slope construction. The level of a fault's activity can be critical for (1) locating buildings, tanks, and pipelines and (2) assessing the seismic shaking and tsunami hazard to infrastructure and people in

273-408: A fault's age by studying soil features seen in shallow excavations and geomorphology seen in aerial photographs. Subsurface clues include shears and their relationships to carbonate nodules , eroded clay, and iron oxide mineralization, in the case of older soil, and lack of such signs in the case of younger soil. Radiocarbon dating of organic material buried next to or over a fault shear

312-463: A large mountain mass or compact group of connected mountains forming an independent portion of a range. The Face on Mars is an example of an extraterrestrial massif. Massifs may also form underwater, as with the Atlantis Massif . Geologic fault In geology , a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as

351-477: A result of rock-mass movements. Large faults within Earth 's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of subduction zones or transform faults . Energy release associated with rapid movement on active faults is the cause of most earthquakes . Faults may also displace slowly, by aseismic creep . A fault plane

390-407: Is a principal mountain mass, such as a compact portion of a mountain range , containing one or more summits (e.g. France's Massif Central ). In mountaineering literature, a massif is frequently used to denote the main mass of an individual mountain. As a purely scientific term in geology , however, a "massif" is separately and more specifically defined as a section of a planet's crust that

429-534: Is an unmanaged winter facility with 12 beds. From summer 2017, the performance of civil marriage ceremonies within the Margherita Hut was authorised by the mayor of the nearest town, Alagna Valsesia . However, couples wishing to get married will be unable to arrive by helicopter, and will still have to make the long glacier hike via one of the normal mountaineering routes. The hut can only be accessed on foot. The traditional approach starts from Alagna Valsesia ,

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468-402: Is demarcated by faults or flexures . In the movement of the crust, a massif tends to retain its internal structure while being displaced as a whole. A massif is a smaller structural unit than a tectonic plate and is considered the fourth-largest driving force in geomorphology . The word "massif" originates from French (in which the word also means "massive"), where it is used to refer to

507-543: Is often critical in distinguishing active from inactive faults. From such relationships, paleoseismologists can estimate the sizes of past earthquakes over the past several hundred years, and develop rough projections of future fault activity. Many ore deposits lie on or are associated with faults. This is because the fractured rock associated with fault zones allow for magma ascent or the circulation of mineral-bearing fluids. Intersections of near-vertical faults are often locations of significant ore deposits. An example of

546-444: Is the plane that represents the fracture surface of a fault. A fault trace or fault line is a place where the fault can be seen or mapped on the surface. A fault trace is also the line commonly plotted on geologic maps to represent a fault. A fault zone is a cluster of parallel faults. However, the term is also used for the zone of crushed rock along a single fault. Prolonged motion along closely spaced faults can blur

585-456: The Chesapeake Bay impact crater . Ring faults are the result of a series of overlapping normal faults, forming a circular outline. Fractures created by ring faults may be filled by ring dikes . Synthetic and antithetic are terms used to describe minor faults associated with a major fault. Synthetic faults dip in the same direction as the major fault while the antithetic faults dip in

624-399: The Margherita Hut on the following morning. The walk requires physical fitness and a good knowledge of alpine techniques. [REDACTED] Media related to Capanna Regina Margherita at Wikimedia Commons 45°55′38″N 7°52′37″E  /  45.92722°N 7.87694°E  / 45.92722; 7.87694 Massif A massif ( / m æ ˈ s iː f , ˈ m æ s ɪ f / )

663-414: The crust. A thrust fault has the same sense of motion as a reverse fault, but with the dip of the fault plane at less than 45°. Thrust faults typically form ramps, flats and fault-bend (hanging wall and footwall) folds. A section of a hanging wall or foot wall where a thrust fault formed along a relatively weak bedding plane is known as a flat and a section where the thrust fault cut upward through

702-433: The direction of extension or shortening changes during the deformation but the earlier formed faults remain active. The hade angle is defined as the complement of the dip angle; it is the angle between the fault plane and a vertical plane that strikes parallel to the fault. Ring faults , also known as caldera faults , are faults that occur within collapsed volcanic calderas and the sites of bolide strikes, such as

741-431: The distinction, as the rock between the faults is converted to fault-bound lenses of rock and then progressively crushed. Due to friction and the rigidity of the constituent rocks, the two sides of a fault cannot always glide or flow past each other easily, and so occasionally all movement stops. The regions of higher friction along a fault plane, where it becomes locked, are called asperities . Stress builds up when

780-409: The fault (called a piercing point ). In practice, it is usually only possible to find the slip direction of faults, and an approximation of the heave and throw vector. The two sides of a non-vertical fault are known as the hanging wall and footwall . The hanging wall occurs above the fault plane and the footwall occurs below it. This terminology comes from mining: when working a tabular ore body,

819-532: The fault is the vertical component of the separation and the heave of the fault is the horizontal component, as in "Throw up and heave out". The vector of slip can be qualitatively assessed by studying any drag folding of strata, which may be visible on either side of the fault. Drag folding is a zone of folding close to a fault that likely arises from frictional resistance to movement on the fault. The direction and magnitude of heave and throw can be measured only by finding common intersection points on either side of

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858-461: The fault movement. Faults are mainly classified in terms of the angle that the fault plane makes with the Earth's surface, known as the dip , and the direction of slip along the fault plane. Based on the direction of slip, faults can be categorized as: In a strike-slip fault (also known as a wrench fault , tear fault or transcurrent fault ), the fault surface (plane) is usually near vertical, and

897-406: The fault. A fault in ductile rocks can also release instantaneously when the strain rate is too great. Slip is defined as the relative movement of geological features present on either side of a fault plane. A fault's sense of slip is defined as the relative motion of the rock on each side of the fault concerning the other side. In measuring the horizontal or vertical separation, the throw of

936-428: The footwall moves laterally either left or right with very little vertical motion. Strike-slip faults with left-lateral motion are also known as sinistral faults and those with right-lateral motion as dextral faults. Each is defined by the direction of movement of the ground as would be seen by an observer on the opposite side of the fault. A special class of strike-slip fault is the transform fault when it forms

975-531: The footwall. The dip of most normal faults is at least 60 degrees but some normal faults dip at less than 45 degrees. A downthrown block between two normal faults dipping towards each other is a graben . A block stranded between two grabens, and therefore two normal faults dipping away from each other, is a horst . A sequence of grabens and horsts on the surface of the Earth produces a characteristic basin and range topography . Normal faults can evolve into listric faults, with their plane dip being steeper near

1014-429: The geometric gap, and depending on its rheology , the hanging wall might fold and slide downwards into the gap and produce rollover folding , or break into further faults and blocks which fil in the gap. If faults form, imbrication fans or domino faulting may form. A reverse fault is the opposite of a normal fault—the hanging wall moves up relative to the footwall. Reverse faults indicate compressive shortening of

1053-594: The hut was quite small, in 1907 a newer, lower research centre ("Istituto Mosso") was built near the Salati Pass, in Valsesia Valley ( Alagna Valsesia ), at an elevation of about 2,900 metres (9,500 ft). In 1899 a meteorological station was added. The lowest temperature registered was –41 °C in the winter of 1928–1929; in recent years the lowest was –37.5 °C registered on 25 January 2005. A complete restoration started in 1977. The original hut

1092-491: The implied mechanism of deformation. A fault that passes through different levels of the lithosphere will have many different types of fault rock developed along its surface. Continued dip-slip displacement tends to juxtapose fault rocks characteristic of different crustal levels, with varying degrees of overprinting. This effect is particularly clear in the case of detachment faults and major thrust faults . The main types of fault rock include: In geotechnical engineering ,

1131-464: The largest faults on Earth and give rise to the largest earthquakes. A fault which has a component of dip-slip and a component of strike-slip is termed an oblique-slip fault . Nearly all faults have some component of both dip-slip and strike-slip; hence, defining a fault as oblique requires both dip and strike components to be measurable and significant. Some oblique faults occur within transtensional and transpressional regimes, and others occur where

1170-408: The miner stood with the footwall under his feet and with the hanging wall above him. These terms are important for distinguishing different dip-slip fault types: reverse faults and normal faults. In a reverse fault, the hanging wall displaces upward, while in a normal fault the hanging wall displaces downward. Distinguishing between these two fault types is important for determining the stress regime of

1209-435: The most common. With the passage of time, a regional reversal between tensional and compressional stresses (or vice-versa) might occur, and faults may be reactivated with their relative block movement inverted in opposite directions to the original movement (fault inversion). In such a way, a normal fault may therefore become a reverse fault and vice versa. In a normal fault, the hanging wall moves downward, relative to

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1248-482: The opposite direction. These faults may be accompanied by rollover anticlines (e.g. the Niger Delta Structural Style). All faults have a measurable thickness, made up of deformed rock characteristic of the level in the crust where the faulting happened, of the rock types affected by the fault and of the presence and nature of any mineralising fluids . Fault rocks are classified by their textures and

1287-412: The right time for—and type of— igneous differentiation . At a given time differentiated magmas would burst violently out of the fault-traps and head to shallower places in the crust where porphyry copper deposits would be formed. As faults are zones of weakness, they facilitate the interaction of water with the surrounding rock and enhance chemical weathering . The enhanced chemical weathering increases

1326-416: The stratigraphic sequence is known as a ramp . Typically, thrust faults move within formations by forming flats and climbing up sections with ramps. This results in the hanging wall flat (or a portion thereof) lying atop the foot wall ramp as shown in the fault-bend fold diagram. Thrust faults form nappes and klippen in the large thrust belts. Subduction zones are a special class of thrusts that form

1365-400: The surface, then shallower with increased depth, with the fault plane curving into the Earth. They can also form where the hanging wall is absent (such as on a cliff), where the footwall may slump in a manner that creates multiple listric faults. The fault panes of listric faults can further flatten and evolve into a horizontal or near-horizontal plane, where slip progresses horizontally along

1404-564: The town where the first ascent to the summit in 1842 realized by the parish priest of Alagna Valsesia , Giovanni Gnifetti, was organised. The walk to the hut usually takes two days; climbers spend a night at the Gnifetti Hut , the Monte Rosa Hut or the Resegotti Hut (from the latter the climb is very difficult and technical since it requires climbing the Signal ridge), from where they set off for

1443-570: The vicinity. In California, for example, new building construction has been prohibited directly on or near faults that have moved within the Holocene Epoch (the last 11,700 years) of the Earth's geological history. Also, faults that have shown movement during the Holocene plus Pleistocene Epochs (the last 2.6 million years) may receive consideration, especially for critical structures such as power plants, dams, hospitals, and schools. Geologists assess

1482-476: Was directed by the Italian Alpine Club in 1889. The hut was pre-built in the valley, then brought to its final destination by mule and then by men, and assembled on site. It was opened on 18 August 1893, in the presence of Margherita of Savoy , Queen of Italy, to whom the hut is dedicated. The hut soon became an important research centre for high-elevation medicine, under the direction of Angelo Mosso . As

1521-540: Was dismantled and was replaced by the current hut, built in Valsesia in the town of Failungo Superiore, very close to Alagna Valsesia , which opened in 1980. The hut is owned by the central committee of the Italian Alpine Club (CAI), but it is managed by the local CAI section of Varallo Sesia . The hut is open in the summer, from early June to early September, the exact dates varying from year to year. It provides recuperation and accommodation, having 70 beds. In winter, there

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