1995 Antofagasta earthquake

Last updated
1995 Antofagasta earthquake
Relief Map of Chile.jpg
Bullseye1.png
Green pog.svg
Antofagasta
Green pog.svg
Santiago
UTC  time1995-07-30 05:11:23
ISC  event 96080
USGS-ANSS ComCat
Local dateJuly 30, 1995 (1995-07-30)
Local time01:11
Magnitude8.0 Mw [1]
Depth46 km (29 mi) [1]
Epicenter 23°21′S70°19′W / 23.35°S 70.32°W / -23.35; -70.32 [1]
Areas affectedChile
Total damage$1.791 million [2]
Max. intensity VII (Very strong)
Peak acceleration0.29 g [3]
Tsunami2–3 m (6 ft 7 in – 9 ft 10 in) [2] [3]
Casualties3 dead [4]
58–59 injured [2] [4]
575–630 homeless [2]

The 1995 Antofagasta earthquake occurred on July 30 at 05:11 UTC (01:11 local time) with a moment magnitude of 8.0 and a maximum Mercalli intensity of VII (Very strong). 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.

Contents

Tectonic setting

Chile lies along the oblique convergent boundary between the oceanic Nazca Plate and the continental South American plate. Crustal deformation is primarily accommodated by two main types of faulting: strike slip and reverse faulting subduction zone earthquakes. [5] [6] [7] Reverse faulting deformation is taken up by the Peru-Chile Trench, on which this earthquake occurred. [5] Slip rate on the fault is 68–80 mm (2.7–3.1 in)/yr, and as a result the subduction zone is responsible for many megathrust earthquakes in the region. Some of the largest recorded earthquakes ever recorded occurred in the area, such as the 1960 Valdivia earthquake, the 1730 Valparaiso earthquake, and the 1420 Caldera earthquake. [5] [8] Strike slip faulting is taken up the by the Liquiñe-Ofqui Fault. [6] [7] It is responsible for a Mw  7.7 earthquake as part of the aftershock sequence of the 1960 Valdivia earthquake, and potentially was involved with the main rupture as well. [9] [10]

Earthquake

ShakeMap provided by the United States Geological Survey 1995 Antofagasta earthquake USGS shakemap.jpg
ShakeMap provided by the United States Geological Survey

At 1:11 local time on July 30, 1995, a large earthquake struck northern Chile. The Mw  8.0 earthquake struck at a depth of 46 km (29 mi) with an epicenter near Antofagasta. [1] The focal mechanism of this earthquake indicates thrust faulting along the subduction zone, which is consistent with other large earthquakes along the plate boundary in this region. [11] [12] The maximum slip was 5.4 m (18 ft) along a 180 km × 70 km (112 mi × 43 mi) zone of rupture. [13] [11] [14] Foreshock activity was minimal, but large aftershocks lasted a while after the mainshock, with the largest being a shallower Mw  6.4 event with a Modified Mercalli Intensity of VII three days later. [15] The event occurred at the edge of a known seismic gap that produced the 1877 Iquique earthquake, and research suggests that this earthquake may have put more stress on the region as well. [16] The event is not thought to have ruptured the shallow plate interface in the region, leaving it susceptible to future large megathrust earthquakes such as the 1877 event. [16]

Tsunami

The tsunami observed was smaller than expected, however this may be explained by the depth of the event. Maximum run-up height was measured at 2.8 m (9 ft 2 in) at Antofagasta. [12] Tide gauges at Antofagasta, Caldera, and Iqiuque recorded wave heights of 1.5 m (4 ft 11 in), 0.6 m (2 ft 0 in), 0.3 m (1 ft 0 in) respectively. [17] 10 hours after initial rupture, tsunami waves reached French Polynesia where anomalously large run-ups of 2.5 m (8 ft 2 in) and crest-to-trough wave heights of 3 m (9.8 ft) were recorded. [18] Tahiti itself recorded a small tsunami of 20 cm (7.9 in), while Hilo, Hawaii registered heights of 80 cm (31 in).

See also

Related Research Articles

<span class="mw-page-title-main">1960 Valdivia earthquake</span> 9.4–9.6 magnitude earthquake in Chile

The 1960 Valdivia earthquake and tsunami or the Great Chilean earthquake on 22 May 1960 was the most powerful earthquake ever recorded. Various studies have placed it at 9.4–9.6 on the moment magnitude scale. It occurred in the afternoon, and lasted for approximately 10 minutes. The resulting tsunamis affected southern Chile, Hawaii, Japan, the Philippines, eastern New Zealand, southeast Australia, and the Aleutian Islands.

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">1946 Aleutian Islands earthquake</span> Earthquake near the Aleutian Islands, Alaska

The 1946 Aleutian Islands earthquake occurred near the Aleutian Islands, Alaska on April 1, 1946. The shock measured 8.6, Mt 9.3 or 7.4. It had a maximum Mercalli intensity of VI (Strong). It resulted in 165–173 casualties and over US $26 million in damage. The seafloor along the fault was elevated, triggering a Pacific-wide tsunami with multiple destructive waves at heights ranging from 45–138 ft (14–42 m). The tsunami obliterated the Scotch Cap Lighthouse on Unimak Island, Alaska among others, and killed all five lighthouse keepers. Despite the destruction to the Aleutian Island Unimak, the tsunami had almost an imperceptible effect on the Alaskan mainland.

The 1957 Andreanof Islands earthquake occurred at 04:22 local time on March 9 with a moment magnitude estimated between 8.6 and 9.1 and a maximum Modified Mercalli intensity of VIII (Severe). It occurred south of the Andreanof Islands group, which is part of the Aleutian Islands arc. The event occurred along the Aleutian Trench, the convergent plate boundary that separates the Pacific Plate and the North American plates near Alaska. A basin-wide tsunami followed, with effects felt in Alaska and Hawaii, and strong waves recorded across the Pacific rim. Total losses were around $5 million.

<span class="mw-page-title-main">Liquiñe-Ofqui Fault</span> Major geological fault in Northern Chile

The Liquiñe-Ofqui Fault is major geological fault that runs a length of roughly 1,200 kilometres (750 mi) in a NNE-SSW orientation and exhibits current seismicity. It is located in the Chilean Northern Patagonian Andes. It is a dextral intra-arc strike-slip fault. Most large stratovolcanoes of the Southern Volcanic Zone of the Andes are aligned by the fault which allows for the movement of magma and hydrothermal fluids.

The 1996 Biak earthquake, or the Irian Jaya earthquake, occurred on 17 February at 14:59:30 local time near Biak Island, Indonesia. The earthquake, which occurred on the New Guinea Trench, had a moment magnitude of 8.2 and a maximum Mercalli intensity of IX (Violent). The run-up height of the generated tsunami reached 7.7 m (25 ft). The disaster left at least 108 people dead, 423 injured, and 58 missing. It damaged or destroyed 5,043 houses which subsequently made another 10,000 homeless. At Korim, 187 houses were destroyed. Various countries and organizations provided aid and relief in the aftermath of the earthquake.

The 1999 Ambrym earthquake occurred on November 26 at 00:21:17 local time with a moment magnitude of 7.4 and a maximum Mercalli intensity of VII. The back arc thrust event occurred within the Vanuatu archipelago, just to the south of the volcanic island of Ambrym. Vanuatu, which was previously known as New Hebrides, is subject to volcanic and earthquake activity because it lies on an active and destructive plate boundary called the New Hebrides Subduction Zone. While the National Geophysical Data Center classified the total damage as moderate, a destructive local tsunami did result in some deaths, with at least five killed and up to 100 injured.

<span class="mw-page-title-main">Mocha-Villarrica Fault Zone</span> Geological fault zone in Chile and Argentina

The Mocha-Villarrica Fault Zone is a northwest-trending geological fault zone in southern Chile and Argentina. The fault zone runs from Mocha Island in the Pacific to the Andes where it aligns Villarrica, Quetrupillán and Lanín volcanoes. It is one of several fault zones that traverses the north-south Liquiñe-Ofqui Fault.

On January 1, 1996, at 4:05 p.m. Central Indonesia Time, an earthquake with an epicenter in the Makassar Strait struck north of Minahasa on the island of Sulawesi, Indonesia. The earthquake measured 7.9 on the moment magnitude scale and was centered off Tolitoli Regency in Central Sulawesi, or 25 km from the Tonggolobibi village. A tsunami of 2–4 m (6.6–13.1 ft) was triggered by this earthquake as a result. At least 350 buildings were badly damaged, nine people died and 63 people were injured.

<span class="mw-page-title-main">2013 Craig, Alaska earthquake</span> Earthquake in Alaska and British Columbia

The 2013 Craig, Alaska earthquake struck on January 5, at 12:58 am (UTC–7) near the city of Craig and Hydaburg, on Prince of Wales Island. The Mw 7.5 earthquake came nearly three months after an Mw  7.8 quake struck Haida Gwaii on October 28, in 2012. The quake prompted a regional tsunami warning to British Columbia and Alaska, but it was later cancelled. Due to the remote location of the quake, there were no reports of casualties or damage.

The Nemuro-Oki earthquake in scientific literature, occurred on June 17 at 12:55 local time. It struck with an epicenter just off the Nemuro Peninsula in northern Hokkaidō, Japan. It measured 7.8–7.9 on the moment magnitude scale (Mw ), 8.1 on the tsunami magnitude scale (Mt ) and 7.4 on the Japan Meteorological Agency magnitude scale (MJMA ).

An earthquake occurred on 26 August 2012 at 22:37 local time. The earthquake located off the coast of El Salvador measured 7.3 on the moment magnitude scale and had a focal depth of 16.0 kilometres (10 mi). No deaths were reported, however more than 40 people were injured when they were caught in a tsunami generated by the earthquake. Waves from the tsunami were unusually large for an earthquake of this size. The large waves were attributed to the earthquake's unique rupture characteristic. In addition to the absence of fatalities, damage caused by the earthquake and tsunami was minimal as a result of the sparse population around the affected region and the slow rupture characteristic of the event.

<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 2021 Loyalty Islands earthquake was a 7.7 magnitude earthquake that struck offshore between Vanuatu and New Caledonia on February 11, 2021 at 00:19 local time. It is the 4th largest earthquake of 2021.

The 2021 South Sandwich Islands earthquakes were a pair of powerful earthquakes, followed by many strong aftershocks which struck along the South Sandwich Trench in August 2021. The quakes measured 7.5 and 8.1 on the moment magnitude scale, according to the United States Geological Survey. The mainshock is tied with another event in 1929 as the largest earthquake ever recorded in this region, and is tied with the 2021 Kermadec Islands earthquake as the second largest earthquake of 2021.

<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 1979 Yapen earthquake occurred on September 12 at 05:17:51 UTC. It had an epicenter near the coast of Yapen Island in Irian Jaya, Indonesia. Measuring 7.5 on the moment magnitude scale and having a depth of 20 km (12 mi), it caused severe damage on the island. At least 115 were killed due to shaking and a moderate tsunami.

The 1979 Saint Elias earthquake occurred near noon local time on the 28th of February. It measured Mw 7.4–7.6. Though the maximum recorded Modified Mercalli intensity was VII, damage was minimal and there were no casualties due to the remoteness of the faulting. The epicenter lies near the Alaskan border between America and Canada.

<span class="mw-page-title-main">1940 Shakotan earthquake</span> Earthquake in Japan

The 1940 Shakotan earthquake occurred on August 2 at 00:08:22 JST with a moment magnitude (Mw ) of 7.5 and maximum JMA seismic intensity of Shindo 4. The shock had an epicenter off the coast of Hokkaido, Japan. Damage from the shock was comparatively light, but the accomanying tsunami was destructive. The tsunami caused 10 deaths and 24 injuries on Hokkaido, and destroyed homes and boats across the Sea of Japan. The highest tsunami waves were recorded at the coast of Russia while along the coast of Hokkaido, waves were about 2 m.

References

  1. 1 2 3 4 ISC (2017), ISC-GEM Global Instrumental Earthquake Catalogue (1900–2013), Version 4.0, International Seismological Centre
  2. 1 2 3 4 USGS (September 4, 2009), PAGER-CAT Earthquake Catalog, Version 2008_06.1, United States Geological Survey
  3. 1 2 Delouis, B.; Monfret, T.; Dorbath, L.; Pardo, M.; Rivera, L.; Comte, D.; Haessler, H.; Caminade, J. P.; Ponce, L.; Kausel, E.; Cisternas, A. (1997), "The Mw = 8.0 Antofagasta (northern Chile) earthquake of 30 July 1995: A precursor to the end of the large 1877 gap", Bulletin of the Seismological Society of America, 87 (2): 427, Bibcode:1997BuSSA..87..427D, doi:10.1785/BSSA0870020427, S2CID   129629213 [ permanent dead link ]
  4. 1 2 National Geophysical Data Center / World Data Service (NGDC/WDS) (1972), Significant Earthquake Database, National Geophysical Data Center, NOAA, doi:10.7289/V5TD9V7K
  5. 1 2 3 Dura, Tina; Cisternas, Marco; Horton, Benjamin P.; Ely, Lisa; Nelson, Alan; Wesson, Rob; Pilarczyk, Jessica (April 2015). "Coastal evidence for Holocene subduction-zone earthquakes and tsunamis in central Chile". Quaternary Science Reviews. 113: 93–111. doi:10.1016/j.quascirev.2014.10.015 . Retrieved 17 August 2022.
  6. 1 2 De Pascale, Gregory P.; Froude, Melanie; Penna, Ivanna; Hermanns, Reginald L.; Sepúlveda, Sergio A.; Moncada, Daniel; Persico, Mario; Easton, Gabriel; Villalobos, Angelo; Gutiérrez, Francisco (March 2021). "Liquiñe-Ofqui's fast slipping intra-volcanic arc crustal faulting above the subducted Chile Ridge". Scientific Reports. 11 (1): 7069. Bibcode:2021NatSR..11.7069D. doi:10.1038/s41598-021-86413-w. PMC   8007613 . PMID   33782456 . Retrieved 17 August 2022.
  7. 1 2 Cembrano, José; Hervé, Francisco; Lavenu, Alain (1996). "The Liquiñe Ofqui fault zone: a long-lived intra-arc fault system in southern Chile". Tectonophysics. 259 (1–3): 55–66. Bibcode:1996Tectp.259...55C. doi:10.1016/0040-1951(95)00066-6 . Retrieved 17 August 2022.
  8. ↑ Abad M.; Izquierdo T.; Cáceres M.; Bernárdez E.; Rodríguez-Vidal J. (2018). "Coastal boulder deposit as evidence of an ocean-wide prehistoric tsunami originated on the Atacama Desert coast (northern Chile)". Sedimentology. 67 (3): 1505–1528. doi:10.1111/sed.12570. S2CID   135386871.
  9. ↑ Kanamori, Hiroo; Rivera, Luis (1 October 2017). "An M_w = 7.7 slow earthquake in 1960 near the Aysén Fjord region, Chile". Geophysical Journal International. 211: 1. doi:10.1093/GJI/GGX292 . Retrieved 17 August 2022.
  10. ↑ Kanamori, Hiroo (July 2019). "Evidence for a large strike-slip component during the 1960 Chilean earthquake". Geophysical Journal International. 218 (1): 1–32. doi:10.1093/gji/ggz113 . Retrieved 9 July 2022.
  11. 1 2 Barrientos, Sergio. "UPDATE ON NORTHERN CHILE EARTHQUAKE (August 1, 1995)". European Organisation for Astronomical Research in the Southern Hemisphere. Retrieved 17 August 2022.
  12. 1 2 Pritchard, M. E.; Simon, M.; Rosen, P. A.; Hensley, S.; Webb, F. H. (2 August 2002). "Co-seismic slip from the 1995 July 30 Mw= 8.1 Antofagasta, Chile, earthquake as constrained by InSAR and GPS observations". Geophysical Journal International. 150 (2): 362–376. Bibcode:2002GeoJI.150..362P. doi:10.1046/j.1365-246X.2002.01661.x. S2CID   15894908 . Retrieved 17 August 2022.
  13. ↑ "USGS Finite Fault". USGS. Retrieved 17 August 2022.
  14. ↑ Ruegg, J. C.; Barrientos, S.; Campos, J.; Armijo, R.; Serrurier, L.; Lazo, D.; Ortlieb, L. (November 1995). "QUANTIFICATION OF THE 1995 ANTOFAGASTA EARTHQUAKE FROM GEODETIC MEASUREMENTS AND MODELLING" (PDF). International Geological Correlation Program Project 367: Late Quaternary Coastal Records of Rapid Change: Application Ta Present and Future Conditions. Retrieved 18 August 2022.
  15. ↑ "USGS Nearby Seismicity". USGS. Retrieved 17 August 2022.
  16. 1 2 Métois, M.; Socquet, A.; Vigny, C.; Carrizo, D.; Peyrat, S.; Delorme, A.; Maureire, E.; Valderas-Bermejo, M.-C.; Ortega, I. (3 September 2013). "Revisiting the North Chile seismic gap segmentation using GPS-derived interseismic coupling". Geophysical Journal International. 194 (3): 1283–1294. doi:10.1093/gji/ggt183 . Retrieved 18 August 2022.
  17. ↑ Ihmlé, Pierre F.; Ruegg, Jean-Claude (October 1997). "Source tomography by simulated annealing using broad-band surface waves and geodetic data: application to the Mw=8.1 Chile 1995 event". Geophysical Journal International. 131 (1): 146–158. Bibcode:1997GeoJI.131..146I. doi:10.1111/j.1365-246X.1997.tb00601.x . Retrieved 18 August 2022.
  18. ↑ Guibourg, Sandrine; Heinrich, Phillippe; Roche, Roger (1 April 1997). "Numerical modeling of the 1995 Chilean Tsunami. Impact on French Polynesia". Geophysical Research Letters. 24 (7): 775–778. Bibcode:1997GeoRL..24..775G. doi:10.1029/97GL00317. S2CID   129776108 . Retrieved 18 August 2022.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.