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84-562: Los Andes (i.e.: The Andes ) is a department located in Salta Province , Argentina . It is the second largest by area in the province, after Rivadavia Department , and its capital is the town of San Antonio de los Cobres . The department is located in the western area of the province, on the eastern side of the Andes , and includes the Puna de Atacama . It borders with Antofagasta Region ( Chile ),

168-571: A depth of less than 70 km (43 mi) are classified as "shallow-focus" earthquakes, while those with a focal depth between 70 and 300 km (43 and 186 mi) are commonly termed "mid-focus" or "intermediate-depth" earthquakes. In subduction zones, where older and colder oceanic crust descends beneath another tectonic plate, deep-focus earthquakes may occur at much greater depths (ranging from 300 to 700 km (190 to 430 mi)). These seismically active areas of subduction are known as Wadati–Benioff zones . Deep-focus earthquakes occur at

252-488: A depth where the subducted lithosphere should no longer be brittle, due to the high temperature and pressure. A possible mechanism for the generation of deep-focus earthquakes is faulting caused by olivine undergoing a phase transition into a spinel structure. Earthquakes often occur in volcanic regions and are caused there, both by tectonic faults and the movement of magma in volcanoes . Such earthquakes can serve as an early warning of volcanic eruptions, as during

336-475: A few exceptions to this: Supershear earthquake ruptures are known to have propagated at speeds greater than the S wave velocity. These have so far all been observed during large strike-slip events. The unusually wide zone of damage caused by the 2001 Kunlun earthquake has been attributed to the effects of the sonic boom developed in such earthquakes. Slow earthquake ruptures travel at unusually low velocities. A particularly dangerous form of slow earthquake

420-454: A particular location in the Earth is the average rate of seismic energy release per unit volume. In its most general sense, the word earthquake is used to describe any seismic event that generates seismic waves. Earthquakes can occur naturally or be induced by human activities, such as mining , fracking , and nuclear tests . The initial point of rupture is called the hypocenter or focus, while

504-555: A particular location in the Earth is the average rate of seismic energy release per unit volume. One of the most devastating earthquakes in recorded history was the 1556 Shaanxi earthquake , which occurred on 23 January 1556 in Shaanxi , China. More than 830,000 people died. Most houses in the area were yaodongs —dwellings carved out of loess hillsides—and many victims were killed when these structures collapsed. The 1976 Tangshan earthquake , which killed between 240,000 and 655,000 people,

588-730: A single rupture) are approximately 1,000 km (620 mi). Examples are the earthquakes in Alaska (1957) , Chile (1960) , and Sumatra (2004) , all in subduction zones. The longest earthquake ruptures on strike-slip faults, like the San Andreas Fault ( 1857 , 1906 ), the North Anatolian Fault in Turkey ( 1939 ), and the Denali Fault in Alaska ( 2002 ), are about half to one third as long as

672-515: Is a theory that earthquakes can recur in a regular pattern. Earthquake clustering has been observed, for example, in Parkfield, California where a long-term research study is being conducted around the Parkfield earthquake cluster. An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. Rapid changes of stress between rocks, and the stress from the original earthquake are

756-520: Is converted into heat generated by friction. Therefore, earthquakes lower the Earth's available elastic potential energy and raise its temperature, though these changes are negligible compared to the conductive and convective flow of heat out from the Earth's deep interior. There are three main types of fault, all of which may cause an interplate earthquake : normal, reverse (thrust), and strike-slip. Normal and reverse faulting are examples of dip-slip, where

840-400: Is divided into 754 Flinn–Engdahl regions (F-E regions), which are based on political and geographical boundaries as well as seismic activity. More active zones are divided into smaller F-E regions whereas less active zones belong to larger F-E regions. Standard reporting of earthquakes includes its magnitude , date and time of occurrence, geographic coordinates of its epicenter , depth of

924-508: Is home to a number of natural, social and historic attractions. The provincial capital city, also named Salta and nicknamed "La Linda" ("The beautiful") is both an important tourist destination, and the centre point for visiting the rest of the province. The city holds different attractions; among them are its colonial houses and cathedral, and the Museum of High Altitude Archaeology (Spanish: Museo de Arqueología de Alta Montaña de Salta ) that holds

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1008-654: Is influenced by tectonic movements along faults, including normal, reverse (thrust), and strike-slip faults, with energy release and rupture dynamics governed by the elastic-rebound theory . Efforts to manage earthquake risks involve prediction, forecasting, and preparedness, including seismic retrofitting and earthquake engineering to design structures that withstand shaking. The cultural impact of earthquakes spans myths, religious beliefs, and modern media, reflecting their profound influence on human societies. Similar seismic phenomena, known as marsquakes and moonquakes , have been observed on other celestial bodies, indicating

1092-532: Is probably a statistical fluctuation rather than a systematic trend. More detailed statistics on the size and frequency of earthquakes is available from the United States Geological Survey. A recent increase in the number of major earthquakes has been noted, which could be explained by a cyclical pattern of periods of intense tectonic activity, interspersed with longer periods of low intensity. However, accurate recordings of earthquakes only began in

1176-423: Is proportional to the area of the fault that ruptures and the stress drop. Therefore, the longer the length and the wider the width of the faulted area, the larger the resulting magnitude. The most important parameter controlling the maximum earthquake magnitude on a fault, however, is not the maximum available length, but the available width because the latter varies by a factor of 20. Along converging plate margins,

1260-544: Is sent to the rest of Argentina and other countries. The plant in San Martín de Tabacal is the most important of them. The famous wines of the Valles Calchaquíes region (mainly Torrontés , Malbec and Cabernet Sauvignon ) near Cafayate are produced in numerous vineyards of diverse sizes. American breeds of cattle are raised only on the humid subtropical east, along with some sheep and goats . The Salta province

1344-410: Is the tsunami earthquake , observed where the relatively low felt intensities, caused by the slow propagation speed of some great earthquakes, fail to alert the population of the neighboring coast, as in the 1896 Sanriku earthquake . During an earthquake, high temperatures can develop at the fault plane, increasing pore pressure and consequently vaporization of the groundwater already contained within

1428-454: The 1960 Valdivia earthquake in Chile, the largest ever recorded at 9.5 magnitude. Earthquakes result in various effects, such as ground shaking and soil liquefaction , leading to significant damage and loss of life. When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami . Earthquakes can trigger landslides . Earthquakes' occurrence

1512-400: The 1980 eruption of Mount St. Helens . Earthquake swarms can serve as markers for the location of the flowing magma throughout the volcanoes. These swarms can be recorded by seismometers and tiltmeters (a device that measures ground slope) and used as sensors to predict imminent or upcoming eruptions. A tectonic earthquake begins as an area of initial slip on the fault surface that forms

1596-587: The 2004 Indian Ocean earthquake is simultaneously one of the deadliest earthquakes in history. Earthquakes that caused the greatest loss of life, while powerful, were deadly because of their proximity to either heavily populated areas or the ocean, where earthquakes often create tsunamis that can devastate communities thousands of kilometers away. Regions most at risk for great loss of life include those where earthquakes are relatively rare but powerful, and poor regions with lax, unenforced, or nonexistent seismic building codes. Tectonic earthquakes occur anywhere on

1680-464: The Argentine Declaration of Independence , Bolivia annexed Tarija in 1826. In 1834, Jujuy withdrew from Salta and became a separate province. The borders of Salta were further reduced in 1900, with the loss of Yacuiba to Bolivia. The National Government of Los Andes, constituted from the province in 1902 with a capital at San Antonio de los Cobres , was returned to Salta Province in 1943 as

1764-508: The Diablillos mine . Agriculture and its derived industries are still an important activity in the province, adding over 10% to output. Tobacco , sugar cane and viticulture are the most important and produce most of the exports from the area. Other crops mostly for local consumption are maize , beans , citrus , bananas , and tomatoes . The sugar cane is processed in plants in Salta before it

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1848-490: The Himalayan Mountains . With the rapid growth of mega-cities such as Mexico City, Tokyo, and Tehran in areas of high seismic risk , some seismologists are warning that a single earthquake may claim the lives of up to three million people. While most earthquakes are caused by the movement of the Earth's tectonic plates , human activity can also produce earthquakes. Activities both above ground and below may change

1932-517: The Muslims have a mosque, both in Salta City. Salta's Jews are mostly of Ashkenazim origin, but there are also a few Sefardim families. The province is governed as representative and republican form of government. The provincial government is divided into three branches: the executive, headed by a popularly elected governor, who appoints the cabinet; the legislative ; and the judiciary , headed by

2016-669: The Tropic of Capricorn , it has a wide range of climates due to variation in altitude and the influence of orography. The orientation of the Andes influences the distribution of precipitation within the province. The easternmost parts of the province have a hot semi-arid climate ( Köppen BSh ) with a rainy season in the summer. The mean annual temperature and precipitation are 20 °C (68.0 °F) and 500 millimetres (19.7 in). Temperatures can reach up to 47 °C or 116.6 °F during summer, while they can fall down to −5 °C or 23 °F during winter. The first slopes of

2100-426: The brittle-ductile transition zone and upwards by the ground surface. The mechanics of this process are poorly understood because it is difficult either to recreate such rapid movements in a laboratory or to record seismic waves close to a nucleation zone due to strong ground motion. In most cases, the rupture speed approaches, but does not exceed, the shear wave (S wave) velocity of the surrounding rock. There are

2184-959: The collapse of the Soviet Union and an Indian Sikh community has been living in Rosario de la Frontera since the 1940s. Other foreign people settled in the province are the Greek Cypriots , the Chinese , the Germans , the Francs , the Chileans , the Bolivians , the Paraguayans and the Slavs from the Adriatic (mainly Serbs and Croats ). The Jewish community has a synagogue and

2268-413: The least principal stress. Strike-slip faulting is intermediate between the other two types described above. This difference in stress regime in the three faulting environments can contribute to differences in stress drop during faulting, which contributes to differences in the radiated energy, regardless of fault dimensions. For every unit increase in magnitude, there is a roughly thirty-fold increase in

2352-406: The lithosphere that creates seismic waves . Earthquakes can range in intensity , from those so weak they cannot be felt, to those violent enough to propel objects and people into the air, damage critical infrastructure, and wreak destruction across entire cities. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at

2436-541: The 20th century and has been inferred for older anomalous clusters of large earthquakes in the Middle East. It is estimated that around 500,000 earthquakes occur each year, detectable with current instrumentation. About 100,000 of these can be felt. Minor earthquakes occur very frequently around the world in places like California and Alaska in the U.S., as well as in El Salvador, Mexico, Guatemala, Chile, Peru, Indonesia,

2520-433: The 21st century. Seismic waves travel through the Earth's interior and can be recorded by seismometers at great distances. The surface-wave magnitude was developed in the 1950s as a means to measure remote earthquakes and to improve the accuracy for larger events. The moment magnitude scale not only measures the amplitude of the shock but also takes into account the seismic moment (total rupture area, average slip of

2604-555: The Altiplano is a plateau at 3,000 to 4,000 metres (9,800 to 13,100 ft) above sea level. This region has a cool semi-arid climate ( Köppen BSk ): high temperatures vary little (since the warmer season is cloudy, and the cooler sunny), ranging from 14 to 21 °C or 57.2 to 69.8 °F; night temperatures go from 6 °C or 42.8 °F in midsummer, to −8 °C or 17.6 °F in midwinter, and extremes under −15 °C or 5 °F might be recorded. All rain falls exclusively in

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2688-460: The Andes force the moist, easterly winds to rise, provoking very high condensation leading to the formation of clouds that generate copious amounts of rain. The eastern slopes of the mountains receive between 1,000 to 1,500 mm (39 to 59 in) of precipitation a year, although some places receive up to 2,500 mm (98 in) of precipitation annually owing to orographic precipitation . Most of

2772-710: The Department of Los Andes . Antonio Alice 's painting, La muerte de Güemes , which received a gold medal at the Centenary Exposition, is on display at the offices of the Salta Provincial Government. The total land area of the province is 155,488 km (60,034 sq mi), making it the sixth largest province by area in Argentina. The main rivers of the province are the Pilcomayo , Bermejo , and

2856-399: The Earth's core was located in 1913 by Beno Gutenberg . S waves and later arriving surface waves do most of the damage compared to P waves. P waves squeeze and expand the material in the same direction they are traveling, whereas S waves shake the ground up and down and back and forth. Earthquakes are not only categorized by their magnitude but also by the place where they occur. The world

2940-481: The Earth. Also, the depth of the hypocenter can be computed roughly. P wave speed S waves speed As a consequence, the first waves of a distant earthquake arrive at an observatory via the Earth's mantle. On average, the kilometer distance to the earthquake is the number of seconds between the P- and S wave times 8. Slight deviations are caused by inhomogeneities of subsurface structure. By such analysis of seismograms,

3024-513: The Juramento, which later becomes the Salado River . Salta Province is located at a geologically active region, and suffers from occasional earthquakes . There have been four earthquakes of note in the province: The 1692 earthquake was the inspiration for Salta's annual citywide festival, held on 16 September, in honor of El Señor y la Virgen del Milagro. Although Salta Province is located near

3108-558: The Philippines, Iran, Pakistan, the Azores in Portugal, Turkey, New Zealand, Greece, Italy, India, Nepal, and Japan. Larger earthquakes occur less frequently, the relationship being exponential ; for example, roughly ten times as many earthquakes larger than magnitude 4 occur than earthquakes larger than magnitude 5. In the (low seismicity) United Kingdom, for example, it has been calculated that

3192-603: The Supreme Court. The Constitution of Salta Province forms the formal law of the province. In Argentina, the most important law enforcement organization is the Argentine Federal Police but the additional work is carried out by the Salta Provincial Police . The province is divided in 23 departments ( Spanish : departamentos ), containing 59 municipalities ( Spanish : municipios ). The capital of

3276-463: The average recurrences are: an earthquake of 3.7–4.6 every year, an earthquake of 4.7–5.5 every 10 years, and an earthquake of 5.6 or larger every 100 years. This is an example of the Gutenberg–Richter law . The number of seismic stations has increased from about 350 in 1931 to many thousands today. As a result, many more earthquakes are reported than in the past, but this is because of

3360-404: The brittle crust. Thus, earthquakes with magnitudes much larger than 8 are not possible. In addition, there exists a hierarchy of stress levels in the three fault types. Thrust faults are generated by the highest, strike-slip by intermediate, and normal faults by the lowest stress levels. This can easily be understood by considering the direction of the greatest principal stress, the direction of

3444-555: The cause of other earthquakes in the past century. A Columbia University paper suggested that the 8.0 magnitude 2008 Sichuan earthquake was induced by loading from the Zipingpu Dam , though the link has not been conclusively proved. The instrumental scales used to describe the size of an earthquake began with the Richter scale in the 1930s. It is a relatively simple measurement of an event's amplitude, and its use has become minimal in

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3528-521: The dip angle of the rupture plane is very shallow, typically about 10 degrees. Thus, the width of the plane within the top brittle crust of the Earth can reach 50–100 km (31–62 mi) (such as in Japan, 2011 , or in Alaska, 1964 ), making the most powerful earthquakes possible. The majority of tectonic earthquakes originate in the Ring of Fire at depths not exceeding tens of kilometers. Earthquakes occurring at

3612-678: The displacement along the fault is in the direction of dip and where movement on them involves a vertical component. Many earthquakes are caused by movement on faults that have components of both dip-slip and strike-slip; this is known as oblique slip. The topmost, brittle part of the Earth's crust, and the cool slabs of the tectonic plates that are descending into the hot mantle, are the only parts of our planet that can store elastic energy and release it in fault ruptures. Rocks hotter than about 300 °C (572 °F) flow in response to stress; they do not rupture in earthquakes. The maximum observed lengths of ruptures and mapped faults (which may break in

3696-439: The distance from the earthquake and the underlying rock or soil makeup. The first scale for measuring earthquake magnitudes was developed by Charles Francis Richter in 1935. Subsequent scales ( seismic magnitude scales ) have retained a key feature, where each unit represents a ten-fold difference in the amplitude of the ground shaking and a 32-fold difference in energy. Subsequent scales are also adjusted to have approximately

3780-543: The early 1900s, so it is too early to categorically state that this is the case. Most of the world's earthquakes (90%, and 81% of the largest) take place in the 40,000-kilometre-long (25,000 mi), horseshoe-shaped zone called the circum-Pacific seismic belt, known as the Pacific Ring of Fire , which for the most part bounds the Pacific plate . Massive earthquakes tend to occur along other plate boundaries too, such as along

3864-403: The earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane . The sides of a fault move past each other smoothly and aseismically only if there are no irregularities or asperities along the fault surface that increases the frictional resistance. Most fault surfaces do have such asperities, which leads to a form of stick-slip behavior . Once

3948-426: The earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, with some of the later earthquakes as damaging as the early ones. Such a pattern was observed in the sequence of about a dozen earthquakes that struck the North Anatolian Fault in Turkey in

4032-498: The energy released. For instance, an earthquake of magnitude 6.0 releases approximately 32 times more energy than a 5.0 magnitude earthquake and a 7.0 magnitude earthquake releases 1,000 times more energy than a 5.0 magnitude earthquake. An 8.6-magnitude earthquake releases the same amount of energy as 10,000 atomic bombs of the size used in World War II . This is so because the energy released in an earthquake, and thus its magnitude,

4116-458: The fact that no single earthquake in the sequence is the main shock, so none has a notably higher magnitude than another. An example of an earthquake swarm is the 2004 activity at Yellowstone National Park . In August 2012, a swarm of earthquakes shook Southern California 's Imperial Valley , showing the most recorded activity in the area since the 1970s. Sometimes a series of earthquakes occur in what has been called an earthquake storm , where

4200-462: The fault has locked, continued relative motion between the plates leads to increasing stress and, therefore, stored strain energy in the volume around the fault surface. This continues until the stress has risen sufficiently to break through the asperity, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy . This energy is released as a combination of radiated elastic strain seismic waves , frictional heating of

4284-411: The fault plane that holds it in place, and fluids can exert a lubricating effect. As thermal overpressurization may provide positive feedback between slip and strength fall at the fault plane, a common opinion is that it may enhance the faulting process instability. After the mainshock, the pressure gradient between the fault plane and the neighboring rock causes a fluid flow that increases pore pressure in

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4368-418: The fault surface, and cracking of the rock, thus causing an earthquake. This process of gradual build-up of strain and stress punctuated by occasional sudden earthquake failure is referred to as the elastic-rebound theory . It is estimated that only 10 percent or less of an earthquake's total energy is radiated as seismic energy. Most of the earthquake's energy is used to power the earthquake fracture growth or

4452-536: The fault, and rigidity of the rock). The Japan Meteorological Agency seismic intensity scale , the Medvedev–Sponheuer–Karnik scale , and the Mercalli intensity scale are based on the observed effects and are related to the intensity of shaking. The shaking of the earth is a common phenomenon that has been experienced by humans from the earliest of times. Before the development of strong-motion accelerometers,

4536-417: The focus. Once the rupture has been initiated, it begins to propagate away from the focus, spreading out along the fault surface. Lateral propagation will continue until either the rupture reaches a barrier, such as the end of a fault segment, or a region on the fault where there is insufficient stress to allow continued rupture. For larger earthquakes, the depth extent of rupture will be constrained downwards by

4620-406: The force that "pushes" the rock mass during the faulting. In the case of normal faults, the rock mass is pushed down in a vertical direction, thus the pushing force ( greatest principal stress) equals the weight of the rock mass itself. In the case of thrusting, the rock mass "escapes" in the direction of the least principal stress, namely upward, lifting the rock mass, and thus, the overburden equals

4704-489: The ground level directly above it is the epicenter . Earthquakes are primarily caused by geological faults , but also by volcanic activity , landslides, and other seismic events. The frequency, type, and size of earthquakes in an area define its seismic activity, reflecting the average rate of seismic energy release. Significant historical earthquakes include the 1556 Shaanxi earthquake in China, with over 830,000 fatalities, and

4788-565: The growing importance of the city, the capital of the intendency of Salta del Tucumán was moved from San Miguel de Tucumán to Salta. The battle of Salta in 1813 freed the territory from Spain , but occasional attacks were mounted from the Viceroyalty of Peru as late as 1826. Gervasio de Posadas created the province of Salta in 1814, containing the current provinces of Salta, Jujuy , and parts of southern Bolivia and northern Chile . Exploiting internal Argentine conflicts that arose after

4872-410: The intensity of a seismic event was estimated based on the observed effects. Magnitude and intensity are not directly related and calculated using different methods. The magnitude of an earthquake is a single value that describes the size of the earthquake at its source. Intensity is the measure of shaking at different locations around the earthquake. Intensity values vary from place to place, depending on

4956-471: The lengths along subducting plate margins, and those along normal faults are even shorter. Normal faults occur mainly in areas where the crust is being extended such as a divergent boundary . Earthquakes associated with normal faults are generally less than magnitude 7. Maximum magnitudes along many normal faults are even more limited because many of them are located along spreading centers, as in Iceland, where

5040-402: The main causes of these aftershocks, along with the crust around the ruptured fault plane as it adjusts to the effects of the mainshock. An aftershock is in the same region as the main shock but always of a smaller magnitude, however, they can still be powerful enough to cause even more damage to buildings that were already previously damaged from the mainshock. If an aftershock is larger than

5124-414: The mainshock, the aftershock is redesignated as the mainshock and the original main shock is redesignated as a foreshock . Aftershocks are formed as the crust around the displaced fault plane adjusts to the effects of the mainshock. Earthquake swarms are sequences of earthquakes striking in a specific area within a short period. They are different from earthquakes followed by a series of aftershocks by

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5208-569: The national average. In 2012, its economy was estimated at $ 30.613 billion pesos (about US$ 6.743 billion) or $ 23,971 pesos (about US$ 5,280) per capita. Manufacturing plays a significant role in Salta, adding 20% to the economy. Gas and petroleum from the Tartagal , Aguas Blancas , Madrejones and Campo Durán centres is transported to Buenos Aires and Rosario by pipes. There is also an oil refinery located at Campo Durán. Mining includes uranium at Iruya , La Poma and San Carlos ; and silver at

5292-404: The precipitation is concentrated in the summer, with winters being dry. The high rainfall on these first slopes creates a thick jungle that extends in a narrow strip along these ranges, creating an area of great species diversity. At higher altitudes on these slopes, the climate is cooler and more humid, with the vegetation consisting of deciduous and pine trees. Between the high altitudes to

5376-572: The province are the Wichí , which make up 24.9% of the total indigenous population followed by the Kolla (21.6%), and the Guaraní (13.7%). As well, only 4,189 persons declared themselves to be Afro-Argentine . The province hosts a diverse foreign community: Christian Levantines of Syrian - Lebanese origin, Spaniards and Italians make up the largest groups. A small Ukrainian community has been there since

5460-402: The province is the city of Salta, which is where the provincial government is located at. 24°47′S 65°25′W  /  24.783°S 65.417°W  / -24.783; -65.417 Earthquake An earthquake  – also called a quake , tremor , or temblor  – is the shaking of the Earth 's surface resulting from a sudden release of energy in

5544-589: The province. Many visit the Cachi mountains and the villages (such as Payogasta ) around it. There are three national parks in Salta: El Rey National Park in the Yungas jungle, Baritú National Park and Los Cardones National Park . Ethno-racial groups in Salta (2022 census) According to the results from the 2010 census [ INDEC ] , the province has a population of 1,214,441. It constitutes 3.0% of

5628-481: The provinces of Jujuy and Catamarca , and the departments of La Poma , Cachi and Chicoana . The territorial strip linking the northern and southern side of La Poma Department separates Los Andes from Rosario de Lerma Department . Towns and municipalities: Other localities and places: Salta Province Before the Spanish conquest , numerous native peoples (now called Diaguitas and Calchaquíes ) lived in

5712-518: The rock. In the coseismic phase, such an increase can significantly affect slip evolution and speed, in the post-seismic phase it can control the Aftershock sequence because, after the main event, pore pressure increase slowly propagates into the surrounding fracture network. From the point of view of the Mohr-Coulomb strength theory , an increase in fluid pressure reduces the normal stress acting on

5796-437: The rupture of geological faults but also by other events such as volcanic activity, landslides, mine blasts, fracking and nuclear tests . An earthquake's point of initial rupture is called its hypocenter or focus. The epicenter is the point at ground level directly above the hypocenter. The seismic activity of an area is the frequency, type, and size of earthquakes experienced over a particular time. The seismicity at

5880-522: The same numeric value within the limits of the scale. Although the mass media commonly reports earthquake magnitudes as "Richter magnitude" or "Richter scale", standard practice by most seismological authorities is to express an earthquake's strength on the moment magnitude scale, which is based on the actual energy released by an earthquake, the static seismic moment. Every earthquake produces different types of seismic waves, which travel through rock with different velocities: Propagation velocity of

5964-464: The seismic waves through solid rock ranges from approx. 3 km/s (1.9 mi/s) up to 13 km/s (8.1 mi/s), depending on the density and elasticity of the medium. In the Earth's interior, the shock- or P waves travel much faster than the S waves (approx. relation 1.7:1). The differences in travel time from the epicenter to the observatory are a measure of the distance and can be used to image both sources of earthquakes and structures within

6048-422: The stresses and strains on the crust, including building reservoirs, extracting resources such as coal or oil, and injecting fluids underground for waste disposal or fracking . Most of these earthquakes have small magnitudes. The 5.7 magnitude 2011 Oklahoma earthquake is thought to have been caused by disposing wastewater from oil production into injection wells , and studies point to the state's oil industry as

6132-456: The summer, with annual totals between 200 and 400 millimetres or 8 and 16 inches. Several salt flats exist in this area. The highest altitudes found in the western parts of the province have a cool arid climate ( Köppen BWk ), with large diurnal ranges (temperature range between day and night). Salta's economy is relatively underdeveloped, yet diverse. Its economy in 2006 was estimated at US$ 5.141 billion or, US$ 4,764 per capita, 45% below

6216-490: The surrounding fracture networks; such an increase may trigger new faulting processes by reactivating adjacent faults, giving rise to aftershocks. Analogously, artificial pore pressure increase, by fluid injection in Earth's crust, may induce seismicity . Tides may trigger some seismicity . Most earthquakes form part of a sequence, related to each other in terms of location and time. Most earthquake clusters consist of small tremors that cause little to no damage, but there

6300-443: The thickness of the brittle layer is only about six kilometres (3.7 mi). Reverse faults occur in areas where the crust is being shortened such as at a convergent boundary . Reverse faults, particularly those along convergent boundaries, are associated with the most powerful earthquakes (called megathrust earthquakes ) including almost all of those of magnitude 8 or more. Megathrust earthquakes are responsible for about 90% of

6384-556: The three frozen Inca mummies found at the Llullaillaco volcano and known as the Children of Llullaillaco . The Tren a las Nubes ("Train to the Clouds") crosses canyons and cliffs before arriving at the 3,775 metres altitude (12,500 feet) of San Antonio de los Cobres . The red-rock formations of the Valles Calchaquíes and the wine-town of Cafayate are the second most visited place in

6468-451: The total population in Argentina. This represented a 12.5% increase in the population compared to 2001 census [ INDEC ] which had 1,079,051 inhabitants. 6.5% of the population or 79,204 persons declared themselves as having Indigenous background , making it one of the provinces that has a high percentage of indigenous people, being ranked 5th behind Chubut , Neuquén , Jujuy and Río Negro . The most populous indigenous groups in

6552-461: The total seismic moment released worldwide. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other; transform boundaries are a particular type of strike-slip fault. Strike-slip faults, particularly continental transforms , can produce major earthquakes up to about magnitude 8. Strike-slip faults tend to be oriented near vertically, resulting in an approximate width of 10 km (6.2 mi) within

6636-505: The universality of such events beyond Earth. An earthquake is the shaking of the surface of Earth resulting from a sudden release of energy in the lithosphere that creates seismic waves . Earthquakes may also be referred to as quakes , tremors , or temblors . The word tremor is also used for non-earthquake seismic rumbling . In its most general sense, an earthquake is any seismic event—whether natural or caused by humans—that generates seismic waves. Earthquakes are caused mostly by

6720-632: The valleys of what is now Salta Province; they formed many different tribes, the Quilmes and Humahuacas among them, which all shared the Cacán language. The Atacamas lived in the Puna , and the Wichís (Matacos), in the Chaco region . The first conquistador to venture into the area was Diego de Almagro in 1535; he was followed by Diego de Rojas. Hernando de Lerma founded San Felipe de Lerma in 1582, following orders of

6804-436: The vast improvement in instrumentation, rather than an increase in the number of earthquakes. The United States Geological Survey (USGS) estimates that, since 1900, there have been an average of 18 major earthquakes (magnitude 7.0–7.9) and one great earthquake (magnitude 8.0 or greater) per year, and that this average has been relatively stable. In recent years, the number of major earthquakes per year has decreased, though this

6888-477: The viceroy Francisco de Toledo, Count of Oropesa ; the name of the city was soon changed to "San Felipe de Salta". By 1650, the city had around five hundred inhabitants. An intendency of "Salta del Tucumán" was created within the Viceroyalty of the Río de la Plata . In 1774, San Ramón de La Nueva Orán was founded between Salta and Tarija (Tarija was added to the intendency later, in 1807). In 1783, in recognition of

6972-483: The west and the low plains to the east lie the valleys. The climate of these valleys is either humid subtropical with dry winters ( Köppen Cwa ) or subtropical highland ( Cwb ), favouring human settlement and agricultural activities. Mean annual precipitation is around 1,000 mm (39 in), most of it during summer. Mean temperatures exceed 20 °C (68.0 °F) during the summer, while during winter, they are below 14 °C (57.2 °F). Further west,

7056-626: Was the deadliest of the 20th century. The 1960 Chilean earthquake is the largest earthquake that has been measured on a seismograph, reaching 9.5 magnitude on 22 May 1960. Its epicenter was near Cañete, Chile. The energy released was approximately twice that of the next most powerful earthquake, the Good Friday earthquake (27 March 1964), which was centered in Prince William Sound , Alaska. The ten largest recorded earthquakes have all been megathrust earthquakes ; however, of these ten, only

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