Related Research Articles
An interplate earthquake is an earthquake that occurs at the boundary between two tectonic plates. Earthquakes of this type account for more than 90 percent of the total seismic energy released around the world. If one plate is trying to move past the other, they will be locked until sufficient stress builds up to cause the plates to slip relative to each other. The slipping process creates an earthquake with relative displacement on either side of the fault, resulting in seismic waves which travel through the Earth and along the Earth's surface. Relative plate motion can be lateral as along a transform fault boundary, vertical if along a convergent boundary or a divergent boundary, and oblique, with horizontal and lateral components at the boundary. Interplate earthquakes associated at a subduction boundary are called megathrust earthquakes, which include most of the Earth's largest earthquakes.
In geology, transpression is a type of strike-slip deformation that deviates from simple shear because of a simultaneous component of shortening perpendicular to the fault plane. This movement ends up resulting in oblique shear. It is generally very unlikely that a deforming body will experience "pure" shortening or "pure" strike-slip. The relative amounts of shortening and strike-slip can be expressed in the convergence angle alpha which ranges from zero to 90 degrees. During shortening, unless material is lost, transpression produces vertical thickening in the crust. Transpression that occurs on a regional scale along plate boundaries is characterized by oblique convergence. More locally, transpression occurs within restraining bends in strike-slip fault zones.
The 2004 Al Hoceima earthquake occurred on 24 February at 02:27:47 local time near the coast of northern Morocco. The strike-slip earthquake measured 6.3 on the moment magnitude scale and had a maximum perceived intensity of IX (Violent) on the Mercalli intensity scale. Between 628 and 631 people were killed, 926 were injured, and up to 15,000 people were made homeless in the Al Hoceima-Imzourene-Beni Abdallah area.
The 856 Damghan earthquake or the 856 Qumis earthquake occurred on 22 December 856. The earthquake had an estimated magnitude of 7.9, and a maximum intensity of X (Extreme) on the Mercalli intensity scale. The meizoseismal area extended for about 350 kilometres (220 mi) along the southern edge of the eastern Alborz mountains of present-day Iran including parts of Tabaristan and Gorgan. The earthquake's epicenter is estimated to be close to the city of Damghan, which was then the capital of the Persian province of Qumis. It caused approximately 200,000 deaths and is listed by the USGS as the sixth deadliest earthquake in recorded history. This death toll has been debated.
The Bangong suture zone is a key location in the central Tibet conjugate fault zone. Approximately 1,200 km long, the suture trends in an east–west orientation. Located in central Tibet between the Lhasa and Qiangtang terranes, it is a discontinuous belt of ophiolites and mélange that is 10–20 km wide, up to 50 km wide in places. The northern part of the fault zone consists of northeast striking sinistral strike-slip faults while the southern part consists of northwest striking right lateral strike-slip faults. These conjugate faults to the north and south of the Bangong intersect with each other along the Bangong-Nujiang suture zone.
The Tian Shan is a mountain range in central Asia that extends through western China, Kazakhstan, and Kyrgyzstan. The Tian Shan is 2,800 kilometres (1,700 mi) long, and up to 7,400 metres (24,300 ft) high. Throughout the Tian Shan there are several intermontane basins separated by high ranges. Plate tectonic theory makes the assumption that deformation is concentrated along plate boundaries. However, active deformation is observed in the Tian Shan, far from plate boundaries. This apparent contradiction of plate tectonic theory makes the Tian Shan a key place to study the dynamics of intracontinental deformation.
Intraplate deformation is the folding, breaking, or flow of the Earth's crust within plates instead of at their margins. This process usually occurs in areas with especially weak crust and upper mantle, such as the Tibetan Plateau. Intraplate deformation brings another aspect to plate tectonic theory.
The El Tigre Fault is a 120 km long, roughly north-south trending, major strike-slip fault located in the Western Precordillera in Argentina. The Precordillera lies just to the east of the Andes mountain range in South America. The northern boundary of the fault is the Jáchal River and its southern boundary is the San Juan River. The fault is divided into three sections based on fault trace geometry, Northern extending between 41–46 km in length, Central extending between 48–53 km in length, and Southern extending 26 km in length. The fault displays a right-lateral (horizontal) motion and has formed in response to stresses from the Nazca Plate subducting under the South American Plate. It is a major fault with crustal significance. The Andes Mountain belt trends with respect to the Nazca Plate/South American Plate convergence zone, and deformation is divided between the Precordilleran thrust faults and the El Tigre strike-slip motion. The El Tigre Fault is currently seismically active.
The Binalud Mountain Range or the Binalud Range is a mountain range that runs in a northwest-southeast direction between the Nishapur and Mashhad regions in Razavi Khorasan Province in northeastern Iran, to the southeast of the Caspian Sea. Although far from the Aladagh Mountains, which lie to the northwest in the Province of North Khorasan, the Binalud Mountains are located in such a way that both the Aladagh Mountains and the Binalud Range lie approximately in the same arc, curving from the northwest to the southeast. The city of Mashhad or Meshed is located in the northeastern part of the Binalud Range, and the city of Nishapur or Neyshabur lies on the southwestern section of the range. Situated somewhat to the west of the Binalud Range proper, and with an elevation of 3211 metres, Mount Binalud is the highest point both of the Binalud Mountains and of Razavi Khorasan Province as a whole.
On December 7, 2015, an earthquake measuring 7.2 on the moment magnitude scale struck Tajikistan 105 km (65 mi) west of Murghab at 07:50 UTC at a depth of 26.0 km (16.2 mi). The earthquake was also felt in neighboring Xinjiang in China, India, Afghanistan, Pakistan and Kyrgyzstan.
The geology of Myanmar is shaped by dramatic, ongoing tectonic processes controlled by shifting tectonic components as the Indian plate slides northwards and towards Southeast Asia. Myanmar spans across parts of three tectonic plates separated by north-trending faults. To the west, a highly oblique subduction zone separates the offshore Indian plate from the Burma microplate, which underlies most of the country. In the center-east of Myanmar, a right lateral strike slip fault extends from south to north across more than 1,000 km (620 mi). These tectonic zones are responsible for large earthquakes in the region. The India-Eurasia plate collision which initiated in the Eocene provides the last geological pieces of Myanmar, and thus Myanmar preserves a more extensive Cenozoic geological record as compared to records of the Mesozoic and Paleozoic eras. Myanmar is physiographically divided into three regions: the Indo-Burman Range, Myanmar Central Belt and the Shan Plateau; these all display an arcuate shape bulging westwards. The varying regional tectonic settings of Myanmar not only give rise to disparate regional features, but they also foster the formation of petroleum basins and a diverse mix of mineral resources.
The 1976 Longling earthquake in Yunnan Province, People's Republic of China, was a doublet earthquake, with two main shocks striking just east of Longling at 12:23:20 and 14:00:22 UTC. The magnitudes were estimated at 6.7 and 6.6, respectively, on the Mw(GCMT) scale, and 6.9 and 7.0 on the Ms scale; Chinese sources put these at 7.4 and 7.3 on the Ms7 scale. The region is noted for the quantity and intensity of its earthquakes, and the complexity of its tectonics, which are closely related to the collision between the Indian and Eurasian tectonic plates.
An earthquake measuring 5.8 Mw struck the province of Sichuan in China at 22:55 local time, 17 June 2019. Changning and Gong counties in Yibin were particularly affected. 13 people died and more than 200 others were injured.
The subduction tectonics of the Philippines is the control of geology over the Philippine archipelago. The Philippine region is seismically active and has been progressively constructed by plates converging towards each other in multiple directions. The region is also known as the Philippine Mobile Belt due to its complex tectonic setting.
The 1979 Ghaenat earthquakes were a series of large earthquakes in Qaen County, Khorasan Province, northeast Iran, near the Afghanistan border. The first mainshock, known as the Korizan earthquake with a surface wave magnitude (Ms ) of 6.6 and moment magnitude (Mw ) of 6.8, struck on November 14, while the Ms 7.1 or Mw 7.2 Koli-Boniabad earthquake struck on November 27. The two mainshocks were assigned a maximum Modified Mercalli intensity of VIII (Severe) and X (Extreme), respectively. The earthquakes caused extensive damage throughout northeastern Iran, killing an estimated 297 to 440 people and left at least 279 injured.
Oblique subduction is a form of subduction for which the convergence direction differs from 90° to the plate boundary. Most convergent boundaries involve oblique subduction, particularly in the Ring of Fire including the Ryukyu, Aleutian, Central America and Chile subduction zones. In general, the obliquity angle is between 15° to 30°. Subduction zones with high obliquity angles include Sunda trench and Ryukyu arc.
The 1997 Bojnurd earthquake occurred on 4 February at 14:07 IRST in Iran. The epicenter of the Mw 6.5 earthquake was in the Kopet Dag mountains of North Khorasan, near the Iran–Turkmenistan border, about 579 km (360 mi) 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.
The Tancheng-Lujiang Fault is a large fault in the east China. It was named after it was initially discovered that it starts from Tancheng, Shandong Province in the north and reaches the Lujiang County in Anhui Province in the south. In fact, the northern section of the Tan-Lu fault has been extending along the north-north-east direction through the Bohai Sea and northeast China to the Sea of Okhotsk, with a length of more than 2,400 kilometers in China. In the history of the earth, its southern section also extended to today's Mount Lu for a time.
The 2019 East Azerbaijan earthquake occurred at 03:17 local-time on November 8, 2019. This earthquake had a moment magnitude of 5.9 and had a shallow depth of 20 km.
References
- 1 2 Shabanian et al. 2012, p.2
- 1 2 Shabanian et al. 2012, p.3
- ↑ Shabanian et al. 2012, p.10
- ↑ Shabanian et al. 2012, p.12
- ↑ Shabanian, Esmaeil; Bellier, Olivier; Siame, Lionel; Arnaud, Nicolas; Abbassi, Mohammad R.; Cochemé, Jean-Jacques (2009-10-01). "New tectonic configuration in NE Iran: Active strike-slip faulting between the Kopeh Dagh and Binalud mountains" (PDF). Tectonics. 28 (5): TC5002. doi:10.1029/2008tc002444. ISSN 1944-9194. S2CID 128612019.
- ↑ Aflaki, M; Mousavi, Z; Ghods, A; Shabanian, E; Vajedian, S; Akbarzadeh, M (1 August 2019). "The 2017 Mw 6 Sefid Sang earthquake and its implication for the geodynamics of NE Iran". Geophysical Journal International. 218 (2): 4. doi:10.1093/gji/ggz172.
