2017 Chiapas earthquake explained

2017 Chiapas earthquake
Timestamp:2017-09-08 04:49:19
Isc-Event:611600536
Anss-Url:us2000ahv0
Local-Time:23:49:21 CDT
Magnitude:8.2

The 2017 Chiapas earthquake struck at 23:49 CDT on 7 September (local time; 04:49 on the 8th UTC) in the Gulf of Tehuantepec off the southern coast of Mexico near the state of Chiapas, approximately 87km (54miles) southwest of Pijijiapan (alternately, 101km (63miles) south-southwest of Tres Picos),[1] with a Mercalli intensity of IX (Violent).[2] The moment magnitude was estimated to be .[3] Mexico's president called it the strongest earthquake recorded in the country in a century. It was also the second strongest recorded in the country's history, behind the magnitude 8.6 earthquake in 1787,[5] the largest recorded globally in 2017 and the largest earthquake worldwide since the 2015 illapel earthquake.[6]

Tectonic setting

The Gulf of Tehuantepec lies above the convergent boundary where the Cocos Plate is being subducted below the North American Plate at a rate of 6.4 cm/yr (2.5 in/yr).[7] [8]

Background

On 6 September, several earthquake alarms in Mexico City were mistakenly activated, leading to the evacuation of buildings. The incident prompted a review of the system.[9]

Earthquake

According to the National Seismological Service (SSN) of Mexico, the epicenter was located in the Gulf of Tehuantepec, about southeast of Tonalá, Chiapas. The United States Geological Survey (USGS) reported that the epicenter was about southwest of Pijijiapan, Chiapas.[10] while the USGS also reported a M 8.2 earthquake after correcting an earlier estimate of M 8.0.[12] The entire thickness of the lithosphere of the Cocos Plate ruptured during the earthquake.[15]

The earthquake is the most powerful in Mexico to be measured by seismographs. Mexican President Enrique Peña Nieto called the earthquake the "largest in at least a century" and said that it was felt by 50 million people.[16]

Geophysicists at the National Autonomous University of Mexico speculated that the earthquake relieved stored pressure in the "Tehuantepec gap", making future earthquakes in the region less likely.[17]

Tsunami

A tsunami with waves of 1m (03feet) and higher was generated by the earthquake and was recorded at Salina Cruz;[18] A tsunami wave of 1.75m (05.74feet) was reported in Chiapas.[19] The Pacific Tsunami Warning Center issued a warning for the entire Pacific coast of Central America, also extending south to Ecuador.[20] [21]

Aftershocks

In the hour following the earthquake, at least 12 aftershocks were recorded by the USGS.[22] As of 00:30 September 14 (UTC Time), the National Seismological Service (SSN) has recorded at least 1,806 aftershocks, of up to a magnitude of 6.1.

CDT timeEpicenterNearby landmarksDepth
+List of aftershocks recorded by USGS[23] Main 7 September 2017 23:49:21 69.71NaN1 8.2
1 8 September 2017 0:01:38 351NaN1 5.7
2 8 September 2017 0:17:42 41.31NaN1 5.4
3 8 September 2017 0:24:40 77km (48miles) southwest of Paredon 50.51NaN1 5.2
4 8 September 2017 0:33:38 87km (54miles) south-southwest of Paredon 351NaN1 5.2
5 8 September 2017 0:57:00 211NaN1 5.1
6 8 September 2017 1:08:47 101NaN1 5.0
7 8 September 2017 2:38:38 83km (52miles) southeast of Salina Cruz 501NaN1 5.3
8 8 September 2017 2:59:57 73km (45miles) southeast of Salina Cruz 501NaN1 5.2
9 8 September 2017 3:34:34 130km (80miles) southwest of Tonalá 161NaN1 5.9
10 8 September 2017 6:25:56 32km (20miles) southeast of Salina Cruz 591NaN1 5.0
11 8 September 2017 6:43:07 42km (26miles) southeast of Salina Cruz 591NaN1 5.2
12 8 September 2017 9:24:59 94km (58miles) southwest of Arriaga 161NaN1 5.3
13 8 September 2017 9:45:00 60km (40miles) southeast of Salina Cruz 971NaN1 5.5
14 8 September 2017 12:02:55 54km (34miles) southeast of Salina Cruz 711NaN1 5.0
15 8 September 2017 13:24:14 20km (10miles) southwest of Salina Cruz 751NaN1 5.1
16 8 September 2017 13:57:23 6km (04miles) southwest of Salina Cruz 651NaN1 5.2
17 8 September 2017 21:32:07 127km (79miles) southwest of Tonalá 201NaN1 5.4
18 8 September 2017 22:08:14 87km (54miles) southeast of Salina Cruz 161NaN1 5.3
19 8 September 2017 23:54:48 154km (96miles) southwest of Pijijiapan 201NaN1 5.6
20 9 September 2017 0:22:16 82km (51miles) southeast of Salina Cruz 161NaN1 5.2
21 9 September 2017 1:24:20 61km (38miles) southeast of Salina Cruz 171NaN1 5.0
22 9 September 2017 7:17:40 52km (32miles) southeast of Salina Cruz 551NaN1 5.4
23 9 September 2017 10:30:09 54km (34miles) southeast of Salina Cruz 261NaN1 5.0
24 9 September 2017 15:26:16 66km (41miles) southeast of Salina Cruz 321NaN1 5.0
25 9 September 2017 22:07:21 111km (69miles) southeast of Salina Cruz 151NaN1 5.8
26 10 September 2017 10:28:50 127km (79miles) southeast of Salina Cruz 201NaN1 5.0
27 11 September 2017 9:55:58 124km (77miles) southeast of Salina Cruz 161NaN1 5.2
28 11 September 2017 16:09:13 140km (90miles) southwest of Tonalá 201NaN1 5.2
29 11 September 2017 20:12:31 126km (78miles) southwest of Tonalá 341NaN1 5.6
30 12 September 2017 0:08:45 111km (69miles) southwest of Pijijiapan 131NaN1 5.3
31 12 September 2017 4:20:01 73km (45miles) south of Salina Cruz 161NaN1 5.0
32 12 September 2017 15:07:30 99km (62miles) southeast of Salina Cruz 161NaN1 5.0

Damage and aftermath

Within Chiapas, an estimated 1.5 million people were affected by the earthquake, with 41,000 homes damaged.[24] [25] Jose Calzada, Minister of Agriculture, reported that at least 98 people had died in the earthquake, including 78 in Oaxaca, 16 in Chiapas and 4 in Tabasco. The Secretariat of the Interior declared a state of emergency for 122 municipalities in Chiapas,[26] and the Mexican Army was deployed to aid in disaster relief.[27] Schools were closed on 8 September in 11 states for safety inspections.[28] Damage in Veracruz was reported, meanwhile the state is expecting the arrival of Hurricane Katia on 9 September. Hurricane Max made landfall in Guerrero state on 14 September, near the earthquake-stricken region.[29]

Buildings in Juchitán de Zaragoza, Oaxaca, closest to the epicenter, were "reduced to rubble" according to reports from the town's mayor.[30]

The earthquake also caused buildings to shake and sway in Mexico City, while also knocking out electricity for 1.8 million people. There were reports of glass shattered at Mexico City International Airport.[31] A highway bridge under construction near Mexico City's new international airport collapsed due to the shaking.[32]

The epicenter was near Mexico's border with Guatemala, where the quake was felt in Guatemala City, and infrastructure damage was reported by CONRED in the nation's south-west. President Jimmy Morales stated that one Guatemalan was killed.[33]

Response

On 11 September, Mexico recalled its aid to the United States, offered in the aftermath of Hurricane Harvey, to focus on earthquake recovery.[34]

United States President Donald Trump called Mexican President Enrique Peña Nieto on 14 September, a week after the earthquake, to express his condolences.[35]

Three years after the earthquake, Governor Alejandro Murat reported that 60,000 homes have been rebuilt, but that many others still have not been. He reported that sixty health centers have been reconstructed, and in 2020 they plan to rebuild 2,000 schools.[36]

See also

External links

Notes and References

  1. M 8.2 – 87 km SW of Pijijiapan, Mexico. 7 September 2017. Subsequently redirected to M 8.2 – 101km SSW of Tres Picos, Mexico.
  2. News: 8 September 2017 . Earthquake of magnitude 8.1 strikes off Mexico's Pacific coast . . 8 September 2017.
  3. Web site: 8 September 2017 . Tsunami Message Number 5 (0653 UTC Fri Sep 8 2017) . National Weather Service (United States) . 8 September 2017 . https://web.archive.org/web/20170908082435/http://tsunami.gov/events/PHEB/2017/09/08/17251000/5/WEPA40/WEPA40.txt . 8 September 2017 . dead .
  4. The earthquake caused all of Mexico City to tremble, prompting people to evacuate after the early warning system was triggered. It also generated a tsunami with waves above tide level; and tsunami alerts were issued for surrounding areas.[3]
  5. News: Richard Hartley. Parkinson. Most powerful earthquake in 230 years hits Mexico sparking tsunami. 8 September 2017. Metro. 8 September 2017.
  6. Web site: World – M7+ in 2017. earthquake.usgs.gov. 8 September 2017.
  7. Singh. S.K.. M. Ordaz. L. Alcantara. N. Shapiro. V. Kostoglodov. J. F. Pacheco. S. Alcocer. C. Gutierrez. R. Quaas. T. Mikumo. E. Ovando. J. Aguirre. D. Almora. J. G. Anderson. M. Ayala. C. Javier. G. Castro. R. Duran. G. Espitia. J. Estrada. E. Guevara. J. Lermo. B. Lopez. O. Lopez. M. Macias. E. Mena. M. Ortega. C. Perez. J. Perez. M. Romo. M. Ramirez. C. Reyes. R. Ruiz. H. Sandoval. M. Torres. E. Vazquez. R. Vazquez. J. M. Velasco. J. Ylizaturri. amp. The Oaxaca earthquake of 30 September 1999 (MW = 7.5). Seismological Research Letters. 71. 1. 67–78. 10.1785/gssrl.71.1.67. 8 September 2017. 2000.
  8. News: Taylor . Adam . 8 September 2017 . Mexico's cataclysmic history of earthquakes . . 8 September 2017.
  9. News: 6 September 2017 . Se activa, por error, alerta sísmica en CDMX; descartan sismo . Seismic alert in CDMX is activated by mistake; disregard earthquake . es . . 7 September 2017.
  10. Web site: 8 September 2017 . Reporte de Sismo: Sismo del día 07 de Septiembre de 2017, Chiapas (M 8.2) . Earthquake Report: Earthquake of 7 September 2017, Chiapas (M 8.2) . es . . 8 September 2017 . https://web.archive.org/web/20170908064045/http://www.ssn.unam.mx/sismicidad/reportes-especiales/2017/SSNMX_rep_esp_20170907_Chiapas_M84.pdf . 8 September 2017 . dead .
  11. The hypocenter was about 45km (28miles) underground, deeper than usual for a relatively new subduction zone. The SSN reported a measurement of M 8.2,[10]
  12. News: Osborne . Hannah . 8 September 2017 . Biggest earthquake to hit Mexico in over a century moved fault by 32 feet . . 8 September 2017.
  13. [12]
  14. The earthquake was a result of normal faulting within the Cocos Plate with a displacement of up to 10m (30feet).[12]
  15. Melgar D. . Ruiz-Angulo A. . Garcia E.S. . Manea M. . Manea V.C. . Xu X. . Ramirez-Herrera M.T. . Zaval-Hidalgo J. . Geng J. . 2018 . Deep embrittlement and complete rupture of the lithosphere during the Mw8.2 Tehuantepec earthquake . Nature Geoscience . 11 . 12 . 955–960 . 10.1038/s41561-018-0229-y. 2018NatGe..11..955M . 133956015 .
  16. News: Partlow . Joshua . 8 September 2017 . At least 58 killed in massive earthquake off Mexico coast . The Washington Post . 8 September 2017.
  17. Wade . Lizzie . 15 September 2017 . Unusual Mexico earthquake may have relieved stress in seismic gap . . 357 . 6356 . 1084 . 10.1126/science.357.6356.1084 . 28912223 . 1095-9203 . 1644869 . 19 September 2017.
  18. News: 8 September 2017 . Mexico earthquake: mass evacuations after strongest tremor in a century . . 8 September 2017.
  19. Web site: Pacific Tsunami Warning Center. Pacific Tsunami Warning Center. Tsunami Message Number 17. National Weather Service. 8 September 2017. Ewa Beach, Hawaii. 8 September 2017. 9 September 2017. https://web.archive.org/web/20170909005429/http://ptwc.weather.gov/ptwc/text.php?id=pacific.TSUPAC.2017.09.08.1827. dead.
  20. News: Mexico hit by 'strongest earthquake in a century' as magnitude 8.2 tremor triggers tsunami waves – latest news. The Telegraph. Graham. Chris. Johnson. Jamie. Strange. Hannah. Badcock. James. 8 September 2017.
  21. Web site: At least six die in huge Mexico quake, small tsunami triggered – Video. 8 September 2017.
  22. News: Malkin . Elisabeth . Ramzy . Austin . 8 September 2017 . Strong Earthquake Hits Off Mexico's Coast . . 8 September 2017.
  23. Web site: Search Results . USDS .
  24. News: Death toll rises to 60 in powerful Mexico earthquake. 9 September 2017. 9 September 2017. Associated Press.
  25. News: 10 September 2017 . Thousands of homes wrecked by huge Mexican quake, death toll at 90 . Reuters . 10 September 2017.
  26. News: Mandujano . Isaín . 8 September 2017 . La Segob declara "emergencia extraordinaria" en 122 municipios de Chiapas por sismo . Secretariat of the Interior declares "extraordinary emergency" in 122 Chiapas municipalities after earthquake . es . . 8 September 2017 . 9 September 2017 . https://web.archive.org/web/20170909011429/http://www.proceso.com.mx/502358/la-segob-declara-emergencia-extraordinaria-en-122-municipios-chiapas-sismo . dead .
  27. News: Garcia . Dennis A. . 8 September 2017 . Sedena aplica Plan DN-III-E en Chiapas y Oaxaca . Sedena applies DN-III-E plan in Chiapas and Oaxaca . es . . 8 September 2017 . 9 September 2017 . https://web.archive.org/web/20170909012151/http://www.eluniversal.com.mx/nacion/seguridad/sedena-aplica-plan-plan-dn-iii-e-en-chiapas-y-oaxaca . dead .
  28. News: Sherman . Cristopher . Castillo . Eduardo . 8 September 2017 . 'The house moved like chewing gum': Dozens killed in Mexico earthquake as country braces for hurricane . Associated Press . . Toronto . 8 September 2017.
  29. News: 15 September 2017 . Hurricane Max lashes earthquake-hit area of southwest Mexico . Channel NewsAsia . 15 September 2017 . 15 September 2017 . https://web.archive.org/web/20170915072131/http://www.channelnewsasia.com/news/world/hurricane-max-lashes-earthquake-hit-area-of-southwest-mexico-9218106 . dead .
  30. News: Cortes . Jose . 8 September 2017 . At least 58 die in Mexico's strongest quake in 85 years . . 8 September 2017.
  31. News: Malkin. Elisabeth. Ramzy. Austin. Mexico Earthquake, at 8.1 Magnitude, Is Felt for Hundreds of Miles. 8 September 2017. The New York Times. 8 September 2017.
  32. News: Navarro . Andrea . 13 September 2017 . In Mexico City Mud, Pena Nieto's $13 Billion Airport Project Bogs Down . . 14 September 2017.
  33. News: Linthicum . Kate . Sanchez . Cecilia . 8 September 2017 . From toppled buildings to at least 32 deaths, Mexico's most powerful quake in years prompts chaos . Los Angeles Times . 8 September 2017.
  34. News: Agren . David . 11 September 2017 . Mexico withdraws Harvey aid offer as it focuses on earthquake recovery . The Guardian . 11 September 2017.
  35. News: Partlow . Joshua . 14 September 2017 . Was it just the cell signal? Mexicans wonder why Trump took so long to offer his earthquake condolences. . The Washington Post . 19 September 2017.
  36. Web site: Familias siguen sin casa en Oaxaca cuando se cumplen tres años del terremoto . www.msn.com . EFE . September 7, 2020 . es . Sep 7, 2020.