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1997 Bojnurd Earthquake
The 1997 Bojnurd earthquake (also known as the Garmkhan earthquake) occurred on 4 February at 14:07 IRST in Iran. The epicenter of the 6.5 earthquake was in the Kopet Dag mountains of North Khorasan, near the Iran–Turkmenistan border, about northeast of Tehran. The earthquake is characterized by shallow strike-slip faulting in a zone of active faults. Seismic activity is present as the Kopet Dag is actively accommodating tectonics through faulting. The earthquake left 88 dead, 1,948 injured, and affected 173 villages, including four which were destroyed. Damage also occurred in Shirvan and Bojnord counties. The total cost of damage was estimated to be over US$ 30 million. Background and tectonics The geology of Iran is dominated by convergence tectonics between the Eurasian Plate and terranes from Gondwana. Two major collisional events occurred; the Cimmerian orogeny which began after the Paleo-Tethys Ocean closed (Late Triassic or Early Jurassic), and the Alpine ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iran Standard Time
Iran Standard Time (IRST) or Iran Time (IT) is the time zone used in Iran. Iran uses a UTC offset UTC+03:30. IRST is defined by the 52.5 degrees east meridian, the same meridian which defines the Iranian calendar and is the official meridian of Iran. Between 2005 and 2008, by decree of President Mahmoud Ahmadinejad, Iran did not observe daylight saving time (DST) (called ''Iran Daylight Time'' or ''IRDT''). It was reintroduced from 21 March 2008. On 21 September 2022, Iran abolished DST and now observes standard time year-round. Daylight Saving Time transitions The dates of DST transitions in Iran were based on the Solar Hijri calendar, the official calendar of Iran, which is in turn based on the March equinox (Nowruz) as determined by astronomical calculation at the meridian for Iran Standard Time (52.5°E or GMT+3.5h). This resulted in the unique situation wherein the dates of DST transitions didn't fall on the same weekday each year as they do in most other countries. DST st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gondwana
Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages of break-up, involving the separation of Antarctica from South America (forming the Drake Passage) and Australia, occurred during the Paleogene. Gondwana was not considered a supercontinent by the earliest definition, since the landmasses of Baltica, Laurentia, and Siberia were separated from it. To differentiate it from the Indian region of the same name (see ), it is also commonly called Gondwanaland. Gondwana was formed by the accretion of several cratons. Eventually, Gondwana became the largest piece of continental crust of the Palaeozoic Era, covering an area of about , about one-fifth of the Earth's surface. During the Carboniferous Period, it merged with Laurasia to form a larger supercontinent called Pangaea. Gondwana (and Pan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zagros Fold And Thrust Belt
The Zagros fold and thrust belt (Zagros FTB) is an approximately long zone of deformed crustal rocks, formed in the foreland of the collision between the Arabian Plate and the Eurasian Plate. It is host to one of the world's largest petroleum provinces, containing about 49% of the established hydrocarbon reserves in fold and thrust belts (FTBs) and about 7% of all reserves globally. Plate tectonic setting The Zagros FTB is formed along a section of the plate boundary that is subject to oblique convergence with the Arabian Plate moving northwards with respect to the Eurasian Plate at about 3 cm per year. The degree of obliqueness reduces southwards along the Zagros, with the collision becoming near orthogonal within the Fars domain. The relative movement between the plates is only partly taken up within the Zagros, the remainder is taken up by deformation in the Alborz mountains and the Lesser Caucasus mountains to the north of the Iranian plateau and along the zone formed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arabian-Nubian Shield
The Arabian-Nubian Shield (ANS) is an exposure of Precambrian crystalline rocks on the flanks of the Red Sea. The crystalline rocks are mostly Neoproterozoic in age. Geographically - and from north to south - the ANS includes parts of Israel, Jordan, Egypt, Saudi Arabia, Sudan, Eritrea, Ethiopia, Yemen, and Somalia. The ANS in the north is exposed as part of the Sahara Desert and Arabian Desert, and in the south in the Ethiopian Highlands, Asir province of Arabia and Yemen Highlands. The ANS was the site of some of man's earliest geologic efforts, principally by the ancient Egyptians to extract gold from the rocks of Egypt and NE Sudan. This was the most easily worked of all metals and does not tarnish. All of the gold deposits in Egypt and northern Sudan were found and exploited by Egyptians. The earliest preserved geologic map was made in 1150 BCE to show the location of gold deposits in Eastern Egypt; it is known as the Turin papyrus. New gold discoveries have been ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tectonic Block
A tectonic block is a part of the Earth's crust that can be treated as a solid rigid crustal block or lithospheric section. A tectonic block may be bounded by faults. It may move from one place to another because of a tectonic shift, and they may also be rotated. A tectonic block may have a proper name for example, the Muness Phyllite Block (which is located in Unst and Uyea in Scotland), or the South China Block The Yangtze Plate, also called the South China Block or the South China Subplate, comprises the bulk of southern China. It is separated on the east from the Okinawa Plate by a rift that forms the Okinawa Trough which is a back-arc basin, on the so .... Early use of the term tectonic block referred to the blocks of rock on either side of a fault. Continental regions may be subdivided into tectonic blocks which are mapped in order to determine earthquake risk. References Tectonics {{tectonics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dasht-e Lut
The Lut Desert, widely referred to as Dasht-e Lut ( fa, دشت لوت, "Emptiness Plain"), is a large salt desert located in the provinces of Kerman and Sistan and Baluchestan, Iran. It is the world's 33rd-largest desert, and was included on UNESCO's World Heritage List on July 17, 2016. The name is derived from 'Lut' which means bare and empty in Persian and 'dasht' which means plain in Persian. The surface of its sand has been measured at temperatures as high as 70.7 °C (159.3 °F), making it one of the world's driest and hottest places. Description Iran is climatically part of the Afro-Asian belt of deserts, which stretches from Mauritania all the way to Mongolia. The patchy, elongated, light-colored feature in the foreground (parallel to the mountain range) is the northernmost of the Dasht dry lakes that stretch southward . Iran's geography consists of a plateau surrounded by mountains and divided into drainage basins. Dasht-e Lut is one of the largest of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kopet Dag
The Köpet Dag, Kopet Dagh, or Koppeh Dagh ( tk, Köpetdag; fa, کپهداغ), also known as the Turkmen-Khorasan Mountain Range, is a mountain range on the border between Turkmenistan and Iran that extends about along the border southeast of the Caspian Sea, stretching northwest-southeast from near the Caspian Sea in the northwest to the Harirud River in the southeast. In the southwest it borders on the parallel eastern endings of the Alborz mountains being together part of the much larger Alpide belt. The highest peak of the range in Turkmenistan is the Mount Rizeh (Kuh-e Rizeh), located at the southwest of the capital Ashgabat and stands at . The highest Iranian summit is Mount Quchan (Kuh-e Quchan) with . Etymology Vambery conjectured that ''köpet'' originates from the Turkmen language where "köp" means "a lot" or "many" and the word "dag" means "mountain" or "peak". He thus translated Köpetdag as "Many mountains (peaks)". He and others noted that in Persian ''koppe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alborz
The Alborz ( fa, البرز) range, also spelled as Alburz, Elburz or Elborz, is a mountain range in northern Iran that stretches from the border of Azerbaijan along the western and entire southern coast of the Caspian Sea and finally runs northeast and merges into the smaller Aladagh Mountains and borders in the northeast on the parallel mountain ridge Kopet Dag in the northern parts of Khorasan. All these mountains are part of the much larger Alpide belt. This mountain range is divided into the Western, Central, and Eastern Alborz Mountains. The Western Alborz Range (usually called the Talysh) runs south-southeastward almost along the western coast of the Caspian Sea. The Central Alborz (the Alborz Mountains in the strictest sense) runs from west to east along the entire southern coast of the Caspian Sea, while the Eastern Alborz Range runs in a northeasterly direction, toward the northern parts of the Khorasan region, southeast of the Caspian Sea. Mount Damavand, the highest m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zagros Mountains
The Zagros Mountains ( ar, جبال زاغروس, translit=Jibal Zaghrus; fa, کوههای زاگرس, Kuh hā-ye Zāgros; ku, چیاکانی زاگرۆس, translit=Çiyakani Zagros; Turkish: ''Zagros Dağları''; Luri: ''Kuh hā-ye Zāgros'' ''کویا زاگرس'') are a long mountain range in Iran, northern Iraq, and southeastern Turkey. This mountain range has a total length of . The Zagros mountain range begins in northwestern Iran and roughly follows Iran's western border while covering much of southeastern Turkey and northeastern Iraq. From this border region, the range continues to the southeast under also the waters of the Persian Gulf. It spans the southern parts of the Armenian highland, the whole length of the western and southwestern Iranian plateau, ending at the Strait of Hormuz. The highest point is Mount Dena, at . Geology The Zagros fold and thrust belt was mainly formed by the collision of two tectonic plates, the Eurasian Plate and the Arabian Plat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deformation (engineering)
In engineering, deformation refers to the change in size or shape of an object. ''Displacements'' are the ''absolute'' change in position of a point on the object. Deflection is the relative change in external displacements on an object. Strain is the ''relative'' internal change in shape of an infinitesimally small cube of material and can be expressed as a non-dimensional change in length or angle of distortion of the cube. Strains are related to the forces acting on the cube, which are known as stress, by a stress-strain curve. The relationship between stress and strain is generally linear and reversible up until the yield point and the deformation is elastic. The linear relationship for a material is known as Young's modulus. Above the yield point, some degree of permanent distortion remains after unloading and is termed plastic deformation. The determination of the stress and strain throughout a solid object is given by the field of strength of materials and for a structure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tethys Ocean
The Tethys Ocean ( el, Τηθύς ''Tēthús''), also called the Tethys Sea or the Neo-Tethys, was a prehistoric ocean that covered most of the Earth during much of the Mesozoic Era and early Cenozoic Era, located between the ancient continents of Gondwana and Laurasia, before the opening of the Indian and Atlantic oceans during the Cretaceous Period. It was preceded by the Paleo-Tethys Ocean, which lasted between the Cambrian and the Early Triassic, while the Neotethys formed during the Late Triassic and lasted until the early Eocene (about 50 million years ago) when it completely closed. A portion known as the Paratethys formed during the Late Jurassic, was isolated during the Oligocene (34 million years ago) and lasted up to the Pliocene (about 5 million years ago), when it largely dried out. Many major seas and lakes of Europe and Western Asia, including the Mediterranean Sea, the Black Sea, the Caspian Sea, and the Aral Sea are thought to be remnants of the Paratethys. Ety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
