2005 Northern Peru earthquake

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2005 Northern Peru earthquake
UTC  time2005-09-26 01:55:37
ISC  event 7951634
USGS-ANSS ComCat
Local dateSeptember 25, 2005 (2005-09-25)
Local time20:55:37 PET (UTC-5)
Duration50 seconds [1]
Magnitude7.5 Mw
7.0 ML [1]
Depth115.0 km (71 mi)
Epicenter 5°40′41″N76°23′53″W / 5.678°N 76.398°W / 5.678; -76.398
Type Normal
Areas affectednorthern Peru
Max. intensity MMI VI (Strong) [2]
Casualties20 dead, 266 injured [3]

At 20:55 PET (01:55 UTC on September 26) on 25 September 2005, an earthquake measuring Mw  7.5 or ML  7.0 struck the Department of Loreto in Peru, resulting in 20 fatalities and 266 injuries, with 1,316 homes damaged or destroyed, mostly in the town of Lamas. It had a maximum perceived intensity of VI (Strong) on the Modified Mercalli Intensity Scale. [2]

Contents

Tectonic setting

A 7,000 km (4,300 mi) convergent boundary lies off the coast of Peru, where the oceanic Nazca plate subducts or dives beneath the continental South American plate. The Peru–Chile Trench marks the location where the two plates meet and converge. The rate of subduction at this boundary varies throughout its length; from 65 mm (2.6 in) per in the north, to 80 mm (3.1 in) per year in the south. [4] The presence of active subduction produces large earthquakes when elastic energy along the plate boundary (megathrust) is released suddenly after decades or centuries of accumulated strain. Earthquakes rupturing the megathrust are known as megathrust earthquakes; capable of generating tsunamis when there is sufficient and sudden uplift of the seafloor, leading to the sudden displacement of the seawater.

Shallow inland crustal earthquakes within the overriding South American plate are caused by internal deformation of the crust within the Andes Mountains; formed by the ongoing convergence. It has been suggested that a large décollement beneath the range is the source of these earthquakes. The fold and thrust belt systems along the eastern foothills of the Andes are seismically active and produce thrust mechanism earthquakes. Normal and strike-slip mechanism earthquakes also occur within the shallow crust. Flat slab subduction beneath the Peruvian Andes also results in deformation of the South American plate, contributing to this occurrence. [5] Earthquakes with similar magnitudes and mechanisms occurred close to the 2005 event in 1990, 1991, 2019 and 2021.

Earthquake

The epicenter was located in the Department of Loreto, about 39 km (24 mi) northwest of Yurimaguas. Focal mechanism solutions indicate that rupture occurred on either a north or south-striking, moderately dipping normal fault. Of these two possible fault orientations, finite fault modeling of globally recorded seismic data from the United States Geological Survey is more consistent with slip on the north-striking fault; the fault modeling also suggests up to 6.4404 m (21.130 ft) of slip near the epicenter. With its hypocenter located roughly 115 km (71 mi) below the surface within the subducted lithosphere of the Nazca plate, the quake extended itself below the Andes and was felt in a large area, including the Peruvian coastal regions and as far away as Bogotá, Colombia, as well as most of Ecuador and western Brazil. [2] It was also the strongest earthquake to hit Peru since 2001. [6]

Impact

At least 20 people died, 266 others were injured and 39,000 residents were displaced, [3] with the earthquake destroying or severely damaging 830 homes [6] and leaving 486 others with minor damage, with most of the affected structures having been built with adobe. [7] In Lamas, 3,000 people were left homeless after the earthquake destroyed 102 houses and severely damaged 498 more, [8] with the town recording five deaths and 60 injuries. [9] Additionally, one woman was killed by a collapsing house in La Libertad, and one more death occurred in San Martín Province. In Moyobamba, the walls of some buildings collapsed. [8] Damage and power outages also occurred in Iquitos, Cajamarca, Chiclayo, Chimbote, Huacho, Tumbes, Sullana, Piura and Pucallpa. [3]

Response

Shortly after the earthquake, ten Red Cross volunteers from Moyobamba visited Lamas to assist affected people. Even with diffcult weather conditions in the area, the Red Cross provided the National Institute of Civil Defence with 1,000 blankets, 50 tents and 200 packs containing clothes. [6]

See also

Related Research Articles

<span class="mw-page-title-main">Convergent boundary</span> Region of active deformation between colliding tectonic plates

A convergent boundary is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a plane where many earthquakes occur, called the Wadati–Benioff zone. These collisions happen on scales of millions to tens of millions of years and can lead to volcanism, earthquakes, orogenesis, destruction of lithosphere, and deformation. Convergent boundaries occur between oceanic-oceanic lithosphere, oceanic-continental lithosphere, and continental-continental lithosphere. The geologic features related to convergent boundaries vary depending on crust types.

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">Nazca Ridge</span> Submarine ridge off the coast of Peru

The Nazca Ridge is a submarine ridge, located on the Nazca Plate off the west coast of South America. This plate and ridge are currently subducting under the South American Plate at a convergent boundary known as the Peru-Chile Trench at approximately 7.7 cm (3.0 in) per year. The Nazca Ridge began subducting obliquely to the collision margin at 11°S, approximately 11.2 Ma, and the current subduction location is 15°S. The ridge is composed of abnormally thick basaltic ocean crust, averaging 18 ±3 km thick. This crust is buoyant, resulting in flat slab subduction under Peru. This flat slab subduction has been associated with the uplift of Pisco Basin and the cessation of Andes volcanism and the uplift of the Fitzcarrald Arch on the South American continent approximately 4 Ma.

The 1995 Antofagasta earthquake occurred on July 30 at 05:11 UTC with a moment magnitude of 8.0 and a maximum Mercalli intensity of VII. The Antofagasta Region in Chile was affected by a moderate tsunami, with three people killed, 58 or 59 injured, and around 600 homeless. Total damage from the earthquake and tsunami amounted to $1.791 million.

The 1906 Ecuador–Colombia earthquake occurred at 10:36:10 (UTC+5) on Wednesday January 31, 1906 off the coast of Ecuador, near Esmeraldas. The earthquake had a moment magnitude of 8.8 and triggered a destructive tsunami that caused at least 500 casualties on the coast of Colombia.

The 1953 Tumbes earthquake occurred on December 12 at 12:31:29 local time near the border between Peru and Ecuador. The shock had a moment magnitude of 7.5, a maximum Mercalli Intensity of VIII (Severe), and occurred in the northwestern offshore area of Tumbes, Peru.

The 1942 Peru earthquake occurred on August 24 at 17:50 local time and was located near the border of the departments of Ica and Arequipa, Peru. It had a magnitude of Mw 8.2 or Ms 8.4.

<span class="mw-page-title-main">Deep-focus earthquake</span>

A deep-focus earthquake in seismology is an earthquake with a hypocenter depth exceeding 300 km. They occur almost exclusively at convergent boundaries in association with subducted oceanic lithosphere. They occur along a dipping tabular zone beneath the subduction zone known as the Wadati–Benioff zone.

The 1992 Murindó earthquake occurred on October 18 at 15:11 UTC with an epicenter in the Department of Chocó, northern Colombia. The shallow magnitude 7.2 earthquake struck northwest of the town of Murindó, killing ten and injured more than a hundred. Thirty-three municipalities were severely damaged.

An earthquake measuring Mw 8.0 struck Peru and the surrounding areas on 26 May 2019 at 02:41 local time. It had a maximum perceived intensity of VII on the Modified Mercalli intensity scale in the towns of Yurimaguas and Lagunas. Two people died and a further 30 were injured. It was the strongest earthquake in 2019 by magnitude.

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">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 1947 Satipo earthquake was the largest earthquake in the sub-Andean region of Peru. It occurred on November 1 at 09:58:57 local time with an epicenter in the Department of Junín. The earthquake had an estimated moment magnitude (Mw ) of 7.7 and focal depth of 20 km (12 mi). Damage was severe in the towns of Satipo and La Merced, and at least 233 people died.

The 1979 Petatlán earthquake, also known as the IBERO earthquake occurred on March 14 at 05:07 local time in the Mexican state of Guerrero. The earthquake had a surface-wave magnitude of Ms  7.6 or moment magnitude of Mw  7.4 and maximum Modified Mercalli intensity of VIII (Severe). The epicenter, onshore, was located 12 km south southeast of Vallecitos de Zaragoza.

<span class="mw-page-title-main">Oblique subduction</span> Tectonic process

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° and 30°. Subduction zones with high obliquity angles include Sunda trench and Ryukyu arc.

<span class="mw-page-title-main">Chile Ridge</span> Submarine oceanic ridge in the Pacific Ocean

The Chile Ridge, also known as the Chile Rise, is a submarine oceanic ridge formed by the divergent plate boundary between the Nazca plate and the Antarctic plate. It extends from the triple junction of the Nazca, Pacific, and Antarctic plates to the Southern coast of Chile. The Chile Ridge is easy to recognize on the map, as the ridge is divided into several segmented fracture zones which are perpendicular to the ridge segments, showing an orthogonal shape toward the spreading direction. The total length of the ridge segments is about 550–600 km.

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">2021 Flores earthquake</span> Earthquake in Indonesia

An earthquake occurred 112 km, offshore, north of Maumere in the Flores Sea on 14 December. The quake had a moment magnitude of 7.3 according to the United States Geological Survey (USGS). One person was killed and 173 others suffered injuries.

Between May 1990 and April 1991, an earthquake sequence occurred in the Department of San Martín, northern Peru. Three large earthquakes of magnitudes (Mw ) 6.5–6.9 occurred in the same region across 11 months, causing extensive damage. At least 189 people were killed in these earthquakes.

References

  1. 1 2 Red Cross (29 September 2005). "Brigadistas de la Cruz Roja Peruana intervienen en las poblaciones afectadas por sismo en selva peruana" (in Spanish). ReliefWeb . Retrieved 28 November 2024.
  2. 1 2 3 "M 7.5 – 39 km NW of Yurimaguas, Peru". United States Geological Survey. Retrieved 19 February 2022.
  3. 1 2 3 "Un día como hoy el norte del Perú fue afectado por un terremoto de 7.5 grados" [On a day like today, northern Peru was affected by a 7.5-degree earthquake] (in Spanish). 25 September 2017. Retrieved 11 December 2022.
  4. ↑ Gavin P. Hayes; Gregory M. Smoczyk; Harley M. Benz; Kevin P. Furlong; Antonio Villaseñor (2015), Seismicity of the Earth 1900–2013, Seismotectonics of South America (Nazca Plate Region) (Open-File Report 2015–1031–E), Open-File Report, United States Geological Survey, doi: 10.3133/ofr20151031E
  5. ↑ S. Devlin; B. L. Isacks; M. E. Pritchard; W. D. Barnhart; R. B. Lohman (2012). "Depths and focal mechanisms of crustal earthquakes in the central Andes determined from teleseismic waveform analysis and InSAR". Tectonics. 31 (2). American Geophysical Union. Bibcode:2012Tecto..31.2002D. doi: 10.1029/2011TC002914 . S2CID   128926791.
  6. 1 2 3 International Federation of Red Cross and Red Crescent Societies (30 September 2005). "Peru: Earthquake Minor Emergency Bulletin No. 1". ReliefWeb . Retrieved 28 November 2024.
  7. ↑ ACT Alliance (28 September 2005). "ACT Alert Perú 1/05: Perú Earthquake". ReliefWeb . Retrieved 28 November 2024.
  8. 1 2 "Five killed in Peru quake, thousands homeless". ReliefWeb . Reuters. 27 September 2005. Retrieved 28 November 2024.
  9. ↑ USGS (26 September 2005). "M=7.5 Northern Peru Preliminary Earthquake Report". ReliefWeb . Retrieved 28 November 2024.
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