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2017 Valparaíso earthquake

Coordinates: 33°02′17″S 72°03′43″W / 33.038°S 72.062°W / -33.038; -72.062 (earthquake)
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2017 Chile earthquake
USGS ShakeMap of the earthquake
UTC time2017-04-24 21:38:30
ISC event610548803
USGS-ANSSComCat
Local dateApril 24, 2017 (2017-04-24)
Local time18:38 CLST (UTC-3)
Duration47 seconds approximately.
Magnitude6.9 Mw[1][2][3]
Depth28 km (USGS)[1]
Epicenter33°02′17″S 72°03′43″W / 33.038°S 72.062°W / -33.038; -72.062 (earthquake)
TypeThrust
Areas affectedCentral Chile
Max. intensityMMI VII (Very strong)[4]
TsunamiYes
ForeshocksYes; 138 in less than 2 days.
Aftershocks13 of 5.0 Mw to 5.9 and 1 of 6.0  Mw, over 1000 in total.
CasualtiesNone

The Valparaíso earthquake of April 2017 was a strong earthquake that shook the cities of Valparaíso and Santiago on Monday, April 24, 2017, at 18:38 local time (21:38 UTC). Its epicenter was located off the coast of the Valparaíso Region and had a magnitude of 6.9 Mw.[1][2][3] On the scale of Mercalli, the earthquake reached an intensity of VII (Very Strong).[4]

Before this seismic event there was an unusual increase in seismic activity (seismic swarm) that began on Saturday, April 22 and before the event of magnitude 6.9 more than 180 foreshocks had been recorded, the strongest being that of magnitude 6.0 that occurred in the dawn of the April 22, 2017.

Subsequent to this event, more than 1000 aftershocks have been recorded, including several earthquakes of magnitude greater than 5.0 and two earthquakes of magnitude 5.8 and 6.0 on Moment magnitude scale that occurred on Friday, April 28, 2017, at 12:30 and 13:05 local time respectively.

Modified Mercalli intensities for some localities

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The earthquake was widely felt throughout the central zone of Chile and in at least two provinces of Argentina.

Intensities of the earthquake on the scale of Mercalli in Chile according to ONEMI.

Locality Region USGS[5] ONEMI[4] Population
Andacollo Coquimbo IV 11k
Canela Coquimbo V 9k
Combarbalá Coquimbo V 13k
Coquimbo City Coquimbo Region V 228k
Illapel Coquimbo V 31k
La Serena City Coquimbo V 221k
Los Vilos Coquimbo V 21k
Monte Patria Coquimbo V 31k
Ovalle Coquimbo V 111k
Paiguano Coquimbo III 4k
Punitaqui Coquimbo V 11k
Río Hurtado Coquimbo IV 4k
Algarrobo Valparaíso VII 14k
Puchuncaví Valparaíso VII 19k
Quillota City Valparaíso VI VI 91k
Greater Valparaíso Valparaíso VI VII 951k
La Ligua Valparaíso VI 35k
El Tabo Valparaíso VI 13k
Colina Metropolitan Region VI 146k
Melipilla Metropolitan Region VI 124k
Puente Alto Metropolitan Region VI 568k
San Bernardo Metropolitan Region V 301k
City of Santiago Metropolitan Region V VI 6.310k (+6M)
Talagante Metropolitan Region VI 74k
Litueche O'Higgins IV 6k
Navidad O'Higgins VII 7k
Paredones O'Higgins IV 6k
Pichilemu O'Higgins IV 16k
Rancagua O'Higgins IV VI 242k
San Fernando O'Higgins IV VI 74k
Santa Cruz O'Higgins IV 38k
Cauquenes Maule V 40k
Constitución Maule IV 46k
Curicó Maule IV 149k
Linares Maule III 94k
Sagrada Familia Maule IV 19k
Cabrero Bio-Bio III 29k
Greater Concepción Bio-Bio III IV 985k

Intensities of the earthquake on the scale of Mercalli in Argentina according to INPRES.

Locality Province USGS[5] INPRES[6] Population
City of San Juan San Juan Province IV IV 447k
City of Mendoza Mendoza Province III IV 1.055k (+1M)

Earthquakes Foreshock

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The first foreshock quake was recorded at 19:46 (local time) and 22:49 (UTC) on April 22, and had a magnitude of 4.8 Mw, with epicenter 32 km west of Valparaíso and 28.1 km deep.[7]

Precursor earthquakes magnitude greater than 5.0
Date Time local Location Coordinates Depth Magnitude MMI Agency.
April 22, 2017 23:36:07 30 km W of Valparaíso 33.02S, 71.95W 20 km 6.0 Mw VI EMSC.[8]
April 22, 2017 23:43:18 30 km W of Valparaíso 33.01S, 71.95W 20 km 5.0 Mw IV EMSC.[9]
April 23, 2017 16:40:10 45 km W of Valparaíso 33.044S, 72.148W 16 km 5.6 Mw IV NEIC.[10]

Aftershock

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After the earthquake more than 1000 aftershocks were registered, the largest one had a magnitude of 6.0 Mw, with an epicenter 14 kilometers south of Valparaíso and 25.9 kilometers deep.[11]

Aftershock of magnitude greater than 5.0
Date Time local Location Coordinates Depth Magnitude MMI Agency.
April 24, 2017 18:45:58 121 km NW of Valparaíso 32.416S, 72.662W 25,9 km 5.5 Mw ? GUC.[12]
April 24, 2017 18:46:04 42 km W of Valparaíso 32.972S, 72.072W 16,4 km 5.2 mb VI NEIC.[13]
April 24, 2017 18:46:24 35 km WNW of Valparaíso 32.931S, 71.984W 16,4 km 5.4 mb VII NEIC.[14]
April 24, 2017 18:48:31 39 km WSW of Valparaíso 33.135S, 72.038W 17,1 km 5.0 mb VI NEIC.[15]
April 24, 2017 22:43:03 46 km W of Valparaíso 33.161S, 72.093W 23,9 km 5.5 Mw IV GUC.[16]
April 27, 2017 02:09:22 39 km SW of Valparaiso 33.265S, 71.956W 22,5 km 5.1 Mw VI NEIC.[17]
April 28, 2017 12:30:06 37 km WSW of Valparaiso 33.219S, 71.969W 22 km 5.9 Mw VII NEIC.[18]
April 28, 2017 12:33:28 47 km SW of Valparaiso 33.30S, 72.02W 20 km 5.1 mb V EMSC.[19]
April 28, 2017 12:49:41 47 km WSW of Valparaiso 33.240S, 72.080W 10 km 5.1 Mw V NEIC.[20]
April 28, 2017 12:58:33 44 km SW of Valparaiso 33.24S, 72.04W 15 km 5.4 Mw IV EMSC.[21]
April 28, 2017 13:05:57 14 km S of Valparaíso 33.166S, 71.662W 25,9 km 6.0 Mw VI GUC.[11]
April 28, 2017 14:41:49 40 km SW of Valparaiso 33.279S, 71.958W 18 km 5.3 Mw VII NEIC.[22]
April 28, 2017 22:46:02 36 km WSW of Valparaiso 33.216S, 71.962W 18,8 km 5.1 Mw V NEIC.[23]
May 13, 2017 13:54:47 30 km W of Valparaiso 32.95S, 71.93W 30 km 5.3 mb VII EMSC.[24]

Tectonic Summary

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The April 24, 2017, M6.9 earthquake west of Valparaiso, Chile, occurred as the result of thrust faulting on or near the subduction zone interface between the Nazca and Pacific plates. At the latitude of this event, the Nazca plate is moving towards the east-northeast at a velocity of 74 mm/year with respect to South America, and begins its subduction beneath the continent at the Peru–Chile Trench, 80 km to the west of the April 24 earthquake. The size, location, depth and mechanism of this event are all consistent with its occurrence on the megathrust interface in this region.[25]

While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Events of the size of the April 24, 2017, earthquake are typically about 40x20 km in size (length x width).[25]

Chile has a long history of massive earthquakes, including the 2010 M 8.8 Maule earthquake in central Chile, which ruptured a ~400 km long section of the plate boundary immediately south of this 2017 event. The April 24, 2017, earthquake lies close to where the Juan Fernández Ridge enters the subduction zone, in a section of the plate boundary that ruptured in a M 8.0 earthquake in March 1985, and previously in the 1906 M 8.2 Valparaiso earthquake (reported by some to be as large as M 8.6). To the north of the Juan Fernandez Ridge, the subduction zone last ruptured in the M 8.3 Illapel earthquake in September 2015. This subduction zone also hosted the largest earthquake on record, the 1960 M 9.5 earthquake in southern Chile. Over the century prior to the April 24, 2017, earthquake, the region within 400 km of this event has hosted 19 M 7+ earthquakes. Prior to the April 24 M 6.9 event, the region immediately surrounding this earthquake hosted 9 other events of M 4.5 or larger over the preceding 2 days, including a M 5.9 earthquake on April 23, 2017. The 6.9 shock was also preceded by 4 seconds by a M~4 foreshock. Within an hour of the M 6.9 earthquake, 4 aftershocks of M 4.7-5.4 had been located.[25]

Magnitude of the earthquake

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Rupture of the earthquake off the coast of Valparaíso.

This list includes information about the earthquake, which were measured by different seismological institutions worldwide.

Date Time local Time UTC Region Coordinates Depth Magnitude Agency.
April 24, 2017 18:38:28 21:38:28 offshore Valparaiso, Chile 33.089S, 72.116W 24,1 km 6.9 Mw GUC.[2]
April 24, 2017 18:38:27 21:38:27 offshore Valparaiso, Chile 33.03S, 71.85W 10 km 6.9 Mw EMSC.[3]
April 24, 2017 18:38:30 21:38:30 offshore Valparaiso, Chile 33.038S, 72.062W 28 km 6.9 Mw NEIC.[1]
April 24, 2017 18:38:21 21:38:21 off the coast of Valparaiso, Chile 33.072S, 72.298W 14 km 6.6 INPRES.[6]
April 24, 2017 18:38:29 21:38:29 near the coast of Valparaiso, Chile 33.02S, 71.86W 20 km 6.8 Mw GFZ.[26]
April 24, 2017 18:38:25 21:38:25 offshore Valparaiso, Chile 32.98S, 71.92W 10 km 6.7 Mw INGV.[27]
April 24, 2017 18:38:26 21:38:26 near the coast of Valparaiso, Chile 32.95S, 71.80W 20 km 6.9 Mw USP.[28]
April 24, 2017 18:38:26 21:38:26 offshore Valparaiso, Chile 33.073S, 72.051W 25 km 6.9 Mw AUST.[29]
April 24, 2017 18:38:25 21:38:25 off the coast of Valparaiso, Chile 33.056S, 72.042W 19 km 6.9 Mw IPGP.[30]

Tsunami

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Tsunami recorded by the buoys on the coast of Valparaíso.

The National Office of Emergency of the Interior Ministry declared a tsunami warning for the coasts of the Valparaíso and O'Higgins regions.[31] A few minutes later, the National Tsunami Service of Chile (SNAM, by its initials in Spanish), dependent on the Hydrographic and Oceanographic Service of the Chilean Navy (SHOA, by its initials in Spanish), ruled out the probability of a tsunami off the coast of Chile.[32] However, if the tsunami was generated, according to the Pacific Tsunami Warning Center (PTWC) the maximum heights were; 16 cm in the city of Valparaíso and 10 cm in the commune of Quintero.[33]

See also

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References

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  1. ^ a b c d "M 6.9 – 40 km W of Valparaiso, Chile". United States Geological Survey. Retrieved 9 July 2018.
  2. ^ a b c "Informe de sismo sensible (in Spanish)". CSN-GUC. Retrieved 9 July 2018.
  3. ^ a b c "M 6.9 – OFFSHORE VALPARAISO, CHILE – 2017-04-24 21:38:27 UTC". EMSC. Retrieved 9 July 2018.
  4. ^ a b c "Sismo de mayor intensidad entre las regiones de Coquimbo y Biobío". ONEMI. Retrieved 9 July 2018.
  5. ^ a b "M 6.9 – 40 km W of Valparaiso, Chile (Pager)". United States Geological Survey. Retrieved 9 July 2018.
  6. ^ a b "Sismo sentido con epicentro en OCEANO PACIFICO (in Spanish)". INPRES. Retrieved 9 July 2018.
  7. ^ "Informe de sismo sensible (in Spanish)". CSN-GUC. Centro Sismológico Nacional. Retrieved 9 July 2018.
  8. ^ "M 6.0 – OFFSHORE VALPARAISO, CHILE – 2017-04-23 02:36:07 UTC". European-Mediterranean Seismological Centre. Retrieved 9 July 2018.
  9. ^ "M 5.0 – OFFSHORE VALPARAISO, CHILE – 2017-04-23 02:43:18 UTC". European-Mediterranean Seismological Centre. Retrieved 9 July 2018.
  10. ^ "M 5.6 – 48 km W of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  11. ^ a b "Informe de sismo (in Spanish)". CSN-GUC. Retrieved 9 July 2018.
  12. ^ "Informe de sismo (in Spanish)". CSN-GUC. Centro Sismológico Nacional. Retrieved 9 July 2018.
  13. ^ "M 5.2 – 42 km W of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  14. ^ "M 5.4 – 35 km WNW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  15. ^ "M 5.0 – 39 km WSW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  16. ^ "Informe de sismo sensible (in Spanish)". CSN-GUC. Centro Sismológico Nacional. Retrieved 9 July 2018.
  17. ^ "M 5.1 – 39 km SW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  18. ^ "M 5.9 – 37 km WSW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  19. ^ "M 5.1 – OFFSHORE VALPARAISO, CHILE – 2017-04-28 15:33:28 UTC". European-Mediterranean Seismological Centre. Retrieved 9 July 2018.
  20. ^ "M 5.1 – 47 km WSW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  21. ^ "M 5.4 – OFFSHORE VALPARAISO, CHILE – 2017-04-28 15:58:33 UTC". European-Mediterranean Seismological Centre. Retrieved 9 July 2018.
  22. ^ "M 5.3 – 40 km SW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  23. ^ "M 5.1 – 36 km WSW of Valparaiso, Chile". Earthquake Hazards Program. United States Geological Survey. Retrieved 9 July 2018.
  24. ^ "M 5.4 – OFFSHORE VALPARAISO, CHILE – 2017-04-28 15:58:33 UTC". European-Mediterranean Seismological Centre. Retrieved 9 July 2018.
  25. ^ a b c "M 6.9 – 40 km W of Valparaiso, Chile". United States Geological Survey. Retrieved 10 July 2018. Public Domain This article incorporates text from this source, which is in the public domain.
  26. ^ "Near Coast of Central Chile". German Research Centre for Geosciences. Retrieved 9 July 2018.
  27. ^ "Terremoto di magnitudo Mwp 6.7 del 24-04-2017 ore 23:38:25 (Italia) in zona: Chile (Peruvian point of view) [Sea]". National Institute of Geophysics and Volcanology. Retrieved 9 July 2018.
  28. ^ "Near Coast of Central Chile (in Portuguese)". University of São Paulo. Retrieved 9 July 2018.
  29. ^ "Earthquake Details". AUST. Geoscience Australia. Retrieved 9 July 2018.
  30. ^ "OFF COAST OF CENTRAL CHILE 2017/04/24 21:38:25 UTC, Mw=6.9". Institut de Physique du Globe de Paris. Retrieved 9 July 2018.
  31. ^ "Sismo de 7.1 grados afectó a zona centro del país y generó alerta preventiva de tsunami" (in Spanish). El Dínamo. 24 April 2017. Retrieved 9 July 2018.
  32. ^ "Onemi cancela evacuación preventiva en Valparaíso y O'Higgins tras sismo de 6,9 grados Richter" (in Spanish). La Tercera. 24 April 2017. Retrieved 9 July 2018.
  33. ^ "2227 UTC MON APR 24 2017". Pacific Tsunami Warning Center. Retrieved 9 July 2018.
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