Intraplate earthquake

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Distribution of seismicity associated with the New Madrid seismic zone (since 1974). This zone of intense earthquake activity is located deep within the interior of the North American plate. New Madrid Seismic Zone activity 1974-2011.svg
Distribution of seismicity associated with the New Madrid seismic zone (since 1974). This zone of intense earthquake activity is located deep within the interior of the North American plate.

An intraplate earthquake is an earthquake that occurs in the interior of a tectonic plate, in contrast to an interplate earthquake on the boundary of a tectonic plate. [1] [2] They are relatively rare compared to the more familiar interplate earthquakes. Buildings far from plate boundaries are rarely protected with seismic retrofitting, so large intraplate earthquakes can inflict heavy damage. Examples of damaging intraplate earthquakes are the devastating 2001 Gujarat earthquake, the 2011 Christchurch earthquake, the 2012 Indian Ocean earthquakes, the 2017 Puebla earthquake, the 1811–1812 New Madrid earthquakes, and the 1886 Charleston earthquake. [3] An earthquake that occurs within a subducting plate is known as an intraslab earthquake.

Contents

Description

The Earth's crust is made up of seven primary and eight secondary tectonic plates, plus dozens of tertiary microplates. The large plates move very slowly on top of convection currents in the underlying mantle. Because they do not all move in the same direction, plates often directly collide or slide laterally along each other, a tectonic environment that makes interplate earthquakes frequent.

By contrast, relatively few earthquakes occur in intraplate environments away from plate junctures. [4] These earthquakes often occur at the location of ancient failed rifts, partial fractures of existing plates, because they may leave a weakness in the crust vulnerable to regional tectonic strain.

Intraslab earthquakes radiate more seismic energy than interplate earthquakes (megathrust earthquakes) of a similar magnitude. This variation makes seismic energy a better measure for the potential macroseismic effects of an earthquake than the more common seismic moment used to calculate the magnitude Mw . [5]

Examples

Examples of intraplate earthquakes include those in Mineral, Virginia, in 2011 (estimated magnitude 5.8), Newcastle, New South Wales in 1989, New Madrid in 1811 and 1812 (estimated magnitude as high as 8.6), [6] the Boston (Cape Ann) earthquake of 1755 (estimated magnitude 6.0 to 6.3), earthquakes felt in New York City in 1737 and 1884 (both quakes estimated at 5.5 magnitude), and the Charleston earthquake in South Carolina in 1886 (estimated magnitude 6.5 to 7.3). The Charleston quake was particularly surprising because, unlike Boston and New York, the area had almost no history of even minor earthquakes.

In 2001, a large intraplate earthquake devastated the region of Gujarat, India. The earthquake occurred far from any plate boundaries, which meant the region above the epicenter was unprepared for earthquakes. In particular, the Kutch district suffered tremendous damage, where the death toll was over 12,000 and the total death toll was higher than 20,000.

In 2017, the 24–29 km deep magnitude 6.5 Botswana earthquake that shook eastern Botswana occurred at over 300 km from the nearest active plate boundary. [7] The event occurred in an underpopulated area of Botswana.

The 1888 earthquake in Río de la Plata was an intraplate quake, [8] from reactivated faults in the Quilmes Trough, far from the boundaries of the South American plate. With a magnitude greater than 5.0 it was felt "in the cities of Buenos Aires, La Plata and other small towns and villages along the Rio de Plata coastal regions." [9] The towns of Punta del Este and Maldonado in Uruguay were hit by a tsunami generated by the quake. [9]

Causes

Many cities live with the seismic risk of a rare, large intraplate earthquake. The cause of these earthquakes is often uncertain. In many cases, the causative fault is deeply buried [7] and sometimes cannot even be found. Some studies have shown that quakes can be caused by fluids moving up the crust along ancient fault zones. [7] [10] In such circumstances, it is difficult to estimate the seismic hazard for a given city, especially if there was only one earthquake in historical times. Some progress is being made in understanding the fault mechanics driving these earthquakes.

Intraplate earthquakes may be unrelated to ancient fault zones and instead caused by deglaciation or erosion. [11]

Prediction

Scientists continue to search for the causes of these earthquakes, and especially for some indication of how often they recur. The best success has come with detailed micro-seismic monitoring, involving dense arrays of seismometers. In this manner, very small earthquakes associated with a causative fault can be located with great accuracy, and in most cases these line up in patterns consistent with faulting. Cryoseisms can sometimes be mistaken for intraplate earthquakes.

Intraslab earthquake

In seismology, an intraslab earthquake occurs within a subducting plate, known as slabs. They are most frequent in older slabs which are colder, whereas younger, warmer slabs rarely produces earthquake. They can be detected within these slabs at depths exceeding 500 km (310 mi); they are also the source of intermediate and deep-focus earthquakes. [12] Intraslab earthquakes at depths 20–60 km (12–37 mi) are considered shallow earthquakes and can be destructive to cities. One of the deadliest earthquakes of the 20th century was the 1970 Ancash earthquake, measuring Mw  7.9 and occurring off the coast of Peru. The 2001 Nisqually and 1949 Olympia earthquakes were also intraslab events. [13]

See also

Related Research Articles

<span class="mw-page-title-main">Earthquake</span> Sudden movement of the Earths crust

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 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 a particular location in the Earth is the average rate of seismic energy release per unit volume.

<span class="mw-page-title-main">New Madrid seismic zone</span> Major seismic zone in the southern and midwestern United States

The New Madrid seismic zone (NMSZ), sometimes called the New Madrid fault line, is a major seismic zone and a prolific source of intraplate earthquakes in the Southern and Midwestern United States, stretching to the southwest from New Madrid, Missouri.

<span class="mw-page-title-main">Cascadia subduction zone</span> Convergent plate boundary that stretches from northern Vancouver Island to Northern California

The Cascadia subduction zone is a 960 km (600 mi) fault at a convergent plate boundary, about 100–200 km (70–100 mi) off the Pacific coast, that stretches from northern Vancouver Island in Canada to Northern California in the United States. It is capable of producing 9.0+ magnitude earthquakes and tsunamis that could reach 30 m (98 ft). The Oregon Department of Emergency Management estimates shaking would last 5–7 minutes along the coast, with strength and intensity decreasing further from the epicenter. It is a very long, sloping subduction zone where the Explorer, Juan de Fuca, and Gorda plates move to the east and slide below the much larger mostly continental North American plate. The zone varies in width and lies offshore beginning near Cape Mendocino, Northern California, passing through Oregon and Washington, and terminating at about Vancouver Island in British Columbia.

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.

Megathrust earthquakes occur at convergent plate boundaries, where one tectonic plate is forced underneath another. The earthquakes are caused by slip along the thrust fault that forms the contact between the two plates. These interplate earthquakes are the planet's most powerful, with moment magnitudes (Mw) that can exceed 9.0. Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes.

<span class="mw-page-title-main">Okhotsk microplate</span> Minor tectonic plate in Asia

The Okhotsk microplate is a proposed minor tectonic plate covering the Kamchatka Peninsula, Magadan Oblast, and Sakhalin Island of Russia; Hokkaido, Kantō and Tōhoku regions of Japan; the Sea of Okhotsk, as well as the disputed Kuril Islands.

A slow earthquake is a discontinuous, earthquake-like event that releases energy over a period of hours to months, rather than the seconds to minutes characteristic of a typical earthquake. First detected using long term strain measurements, most slow earthquakes now appear to be accompanied by fluid flow and related tremor, which can be detected and approximately located using seismometer data filtered appropriately. That is, they are quiet compared to a regular earthquake, but not "silent" as described in the past.

Episodic tremor and slip (ETS) is a seismological phenomenon observed in some subduction zones that is characterized by non-earthquake seismic rumbling, or tremor, and slow slip along the plate interface. Slow slip events are distinguished from earthquakes by their propagation speed and focus. In slow slip events, there is an apparent reversal of crustal motion, although the fault motion remains consistent with the direction of subduction. ETS events themselves are imperceptible to human beings and do not cause damage.

The 1918 Shantou earthquake occurred in Shantou, Guangdong, Republic of China. Serious damage and high casualty numbers were reported in Guangdong and the surrounding provinces. It also caused some damage in British Hong Kong.

<span class="mw-page-title-main">1997 Punitaqui earthquake</span> Earthquake in Chile

The 1997 Punitaqui earthquake occurred at 01:03 UTC on October 15. It had an estimated magnitude of 7.1 Mwc. This earthquake was one of the most destructive in the epicentral area compared to other events of subduction of the same size. The extensive damage to structures was the result of an amplification effect on the ground and the poor quality of building materials, this reflects the potential for damage incurred in an intraplate earthquake with vertical fault and how it can be much greater than what which can cause one of interplate of similar magnitude, and caused severe damage in Chilean cities of La Serena, Vicuña, Ovalle, Illapel and Punitaqui.

This is a list of different types of earthquake.

The 1981 Playa Azul earthquake occurred on October 24, 1981, at 21:22 local time. It was located near Playa Azul, Michoacán, Mexico. The magnitude of the earthquake was Mw 7.2, or Ms 7.3. Three deaths were reported, two from Michoacán and one from Mexico City. Some buildings were damaged in both Michoacán and Mexico City. A small tsunami was registered in Acapulco with a maximum height of 9 cm.

The 1965 Valparaíso earthquake struck near La Ligua in Valparaíso Region, Chile, about 140 km (87 mi) from the capital Santiago on Sunday, March 28 at 12:33 local time. The moment magnitude (Mw ) 7.4–7.6 earthquake killed 400–500 people and inflicted US$1 billion in damage. Many deaths were from El Cobre, a mining location that was wiped out after a series of dam failures caused by the earthquake spilled mineral waste onto the area, burying hundreds of residents. The shock was felt throughout the country and along the Atlantic coast of Argentina.

<span class="mw-page-title-main">1920 Xalapa earthquake</span> Earthquake in Mexico

A moment magnitude 6.3–6.4 earthquake affected parts of Puebla and Veracruz towards the eastern end of the Trans-Mexican Volcanic Belt, Mexico on 3 January 1920 at 22:25 CST. A maximum Modified Mercalli intensity of XI–XII (Extreme) was recorded in the epicenter, between Chilchotla and Patlanalán. The earthquake killed between 648 and 4,000 people; many deaths were attributed to mudslides that swept through settlements along the Huitzilapa and Pescado rivers. Many buildings were badly damaged or totally ruined. The towns of Patlanalá, Barranca Grande, Cosautlán, Quimixtlán and Teocelo were severely affected. Wooden jacales generally performed well during the earthquake but some were destroyed. The total cost of damage was estimated at US$25,000,000.

On the morning of January 5, 1699, a violent earthquake rocked the then Dutch East Indies city of Batavia on the island of Java, now known as the Indonesian capital city of Jakarta. Dutch accounts of the event described the earthquake as being "so heavy and strong" and beyond comparable to other known earthquakes. This event was so large that it was felt throughout west Java, and southern Sumatra.

<span class="mw-page-title-main">2021 Chignik earthquake</span> 7th largest earthquake in the US

An earthquake occurred off the coast of the Alaska Peninsula on July 28, 2021, at 10:15 p.m. local time. The large megathrust earthquake had a moment magnitude of 8.2 according to the United States Geological Survey (USGS). A tsunami warning was issued by the National Oceanic and Atmospheric Administration (NOAA) but later cancelled. The mainshock was followed by a number of aftershocks, including three that were of magnitude 5.9, 6.1 and 6.9 respectively.

The 1983 Hindu Kush earthquake occurred south of Fayzabad, Badakhshan in northeast Afghanistan at 03:52 PST on December 31, 1983, near the border with Pakistan and the USSR. Striking 214.5 km beneath the Hindu Kush mountains, the moment magnitude 7.4 quake affected three countries, killing at least 26 people and injuring several hundred.

The 1950 Calama earthquake occurred near the Argentina–Chile border with an epicenter near Calama, Chile in the Atacama Desert on December 9. The event had a hypocenter depth of 113.9 km, beneath the Caichinque volcanic complex. It measured magnitude Mw  8.2 on the moment magnitude scale, making it the largest intermediate depth earthquake ever recorded on Chilean soil. One person was killed and an unspecified number of people were injured in Calama.

<span class="mw-page-title-main">1867 Java earthquake</span> Earthquake in the Dutch East Indies (present-day Indonesia)

The 1867 Central Java earthquake occurred on June 10 at between 04:20 and 04:30 local time. It struck off the southern coast of the Indonesian island with an estimated moment magnitude of 7.8 (Mw ). Widespread devastation occurred in Central Java, where as many as 700 people were killed. The intermediate-depth intraslab earthquake did not cause a tsunami.

References

  1. ↑ Iwata, Tomotaka; Asano, Kimiyuki (2011). "Characterization of the Heterogeneous Source Model of Intraslab Earthquakes Toward Strong Ground Motion Prediction". Pure and Applied Geophysics. 168 (1–2): 117–124. Bibcode:2011PApGe.168..117I. doi:10.1007/s00024-010-0128-7. S2CID   140602323.
  2. ↑ Senoa, Tetsuzo; Yoshida, Masaki (2004). "Where and why do large shallow intraslab earthquakes occur?". Physics of the Earth and Planetary Interiors. 141 (3): 183–206. Bibcode:2004PEPI..141..183S. doi:10.1016/j.pepi.2003.11.002.
  3. ↑ Hough, Susan E.; Seeber, Leonardo; Armbruster, John G. (October 2003). "Intraplate Triggered Earthquakes: Observations and Interpretation". Bulletin of the Seismological Society of America. 101 (3). Seismological Society of America: 2212–2221. Bibcode:2003BuSSA..93.2212H. CiteSeerX   10.1.1.189.5055 . doi:10.1785/0120020055.
  4. ↑ Yang, Xiaotao (2014). "Seismicity of the Ste. Genevieve Seismic Zone based on Observations from the EarthScope OIINK Flexible Array". Seismological Research Letters. 85 (6): 1285–1294. Bibcode:2014SeiRL..85.1285Y. doi:10.1785/0220140079.
  5. ↑ Leyton, Felipe; Ruiz, Javier A.; Camposa, Jaime; Kausel, Edgar (2009). "Intraplate and interplate earthquakes in Chilean subduction zone: A theoretical and observational comparison". Physics of the Earth and Planetary Interiors. 175 (1): 37–46. Bibcode:2009PEPI..175...37L. doi:10.1016/j.pepi.2008.03.017.citing Choy, G.L.; Boatwright, J.; Kirby, S., 2002. The radiated seismic energy and apparent stress of interplate and intraslab earthquakes at subduction-zone environments: Implications for seismic hazard estimation, in The Cascadia subduction zone and related subduction systems–Seismic structure, intraslab earthquakes and processes, and earthquake hazards, Open-File Report 02–328, pp. 107–114, eds Kirby, S.H.; Wang, K.; Dunlop, S., US Geological Survey, Menlo Park, CA.
  6. ↑ Penick, James L. The New Madrid Earthquakes. Columbia, MO: University of Missouri Press, 1981. ISBN   0-8262-0344-2
  7. 1 2 3 Kolawole, F.; Atekwana, E. A.; Malloy, S.; Stamps, D. S.; Grandin, R.; Abdelsalam, M. G.; Leseane, K.; Shemang, E. M. (2017-09-09). "Aeromagnetic, gravity, and Differential Interferometric Synthetic Aperture Radar analyses reveal the causative fault of the 3 April 2017 Mw6.5 Moiyabana, Botswana, earthquake". Geophysical Research Letters. 44 (17): 8837–8846. Bibcode:2017GeoRL..44.8837K. doi:10.1002/2017gl074620. ISSN   0094-8276. S2CID   134584787.
  8. ↑ Benavídes Sosa, Alberto (1998). "Seismicidad y seismotectónica en Uruguay". Física de la Tierra (in Spanish) (10): 167–186.
  9. 1 2 Rossello, Eduardo Antonio; Heit, Benjamín; Bianchi, Marcelo (2020). "Shallow intraplate seismicity in the Buenos Aires province (Argentina) and surrounding areas: is it related to the Quilmes Trough?". Boletín de Geología. 42 (2): 31–48. doi: 10.18273/revbol.v42n2-2020002 . S2CID   219934403. Archived from the original on 4 August 2022.
  10. ↑ Gardonio, B.; Jolivet, R.; Calais, E.; Leclère, H. (2018-07-13). "The April 2017 Mw6.5 Botswana Earthquake: An Intraplate Event Triggered by Deep Fluids" (PDF). Geophysical Research Letters. 45 (17): 8886–8896. Bibcode:2018GeoRL..45.8886G. doi:10.1029/2018gl078297. ISSN   0094-8276. S2CID   134667492.
  11. ↑ Shobe, Charlie (18 December 2018). "Can Rivers Cause Earthquakes?". Scientific American . Retrieved 26 December 2018.
  12. ↑ Nakajima, Junichi (2019). "Revisiting Intraslab Earthquakes Beneath Kyushu, Japan: Effect of Ridge Subduction on Seismogenesis". Journal of Geophysical Research: Solid Earth. 124 (8): 8660–8678. doi:10.1029/2019JB017869.
  13. ↑ Seno, Tetsuzo; Yoshida, Masaki (2004). "Where and why do large shallow intraslab earthquakes occur?". Physics of The Earth and Planetary Interiors. 141: 183–206. doi:10.1016/j.pepi.2003.11.002.

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