A magnitude 8.3 earthquake struck off the coast of Chile, less than 150 miles from Santiago, prompting a damaging tsunami.
The strong quake shook buildings in Santiago as tsunami alarms sounded in the port town of Valparaiso. It was followed by smaller earthquakes -- which may have been aftershocks or separate events -- in the region up to a preliminary magnitude of 6.4 on the Richter Scale, according to the U.S. Geological Survey.
Asi suenan las alarmas en Valpasaiso a esta hora pic.twitter.com/ERJBliiulT @ucvradio @sitiodelsuceso @reddeemergencia @michelleadamv— @TeAmoValpo (@TeAmoValpo) September 16, 2015
"Once again we must confront a powerful blow from nature," President Michelle Bachelet said in an address to the nation late Wednesday.
There have been reports of structural damage in major cities, and Chile's undersecretary for the ministry of the interior and public security has stated at least five have died and 1 million evacuated from their homes.
Subsecretario entrega nuevo reporte de sismo de mayor intensidad: 5 fallecidos y 1 millón de personas evacuadas pic.twitter.com/Rt2Z4wbE9F— onemichile (@onemichile) September 17, 2015
A BBC reporter based in Chile cited the mayor of Illapel as saying one person died in that town.
The coastline between Arica and Los Lagos was evacuated following the quake, according to authorities in the region.
The earthquake's tremor was so strong that people in Argentina's capital, Buenos Aires, on the other side of the continent, reported feeling it. People in Peru and Brazil also reported feeling the shakes. No injuries were reported outside Chile.
@24HorasTVN @christianpino @biobio @LaRedTV @Mega pic.twitter.com/yp7ay5Cv74— michael montero (@maikelsin) September 16, 2015
Mall de la serena @24HorasTVN @christianpino @biobio @ pic.twitter.com/Tc4LH6Qc7s— michael montero (@maikelsin) September 16, 2015
U.S. officials said the quake struck just offshore in the Pacific at 7:54 p.m. and was centered about 141 miles (228 kilometers) north-northwest of Santiago. The quake occurred about 15 miles (25 kilometres) below the ground, the USGS reported.
Así quedo el Mall de La Serena después del #terremoto pic.twitter.com/PlH0GRHSi2— Kathi Niklitschek (@KathyNik) September 16, 2015
#LTenVivo | Fotos de las evacuaciones preventivas que se registran en la V Región http://t.co/oOSw4zxQ0s pic.twitter.com/K4WJhrHilW— La Tercera (@latercera) September 16, 2015
Big waves caused by the quake hit the coast around 11 p.m. local time. The Pacific Tsunami Warning Center (PTCW) also issued advisories for Hawaii and California. Tsunami waves, which are expected to be small in magnitude, are forecast to hit the coasts of both states starting around 3 a.m. local time in Hawaii and 4:45 a.m. PT in California.
Nations throughout the Pacific are also preparing themselves. New Zealand authorities issued a tsunami warning for the country's east coast and the Chatham Islands. Fiji has also issued a tsunami watch and advisory, Fiji Times reported.
Tsunami waves of 1 to 3 meters (3.3 to 9.8 feet) above tide level are possible on the coast of French Polynesia, according to the Pacific Tsunami Warning Center, while tsunami waves of 0.3 to 1 meter (1 to 3.3 feet) are possible in Mexico, Peru, Japan, Vanuatu, Kribati, Tonga and Russia, among other locations.
There is a network of buoys in the Pacific that forecasters are analyzing to ascertain the scope of the threat. These are aimed at detecting what at the surface may be waves that are mere centimeters tall in the open ocean, but that would grow significantly as they approach land.
PTWC tsunami observations for Chilean coast. #HItsunami pic.twitter.com/Flt0cYF3Nc— Star-Advertiser (@StarAdvertiser) September 17, 2015
Modeled tsunami travel times. The wave from the Chile earthquake will arrive in ~13 hours, or ~5 AM Thursday. pic.twitter.com/gmzgVWy56i— NWS Los Angeles (@NWSLosAngeles) September 17, 2015
Photos and video of tsunami waves and coastal inundation in Chile being shared online.
Update: Coquimbo tide gage station shows 6 meter peak to peak tsunami for Mw8.3 Chile quake (first wave not largest) pic.twitter.com/uR6OqhVE0Z— Jascha Polet (@CPPGeophysics) September 17, 2015
#LTenVivo | Así llegan las olas a Avenida Borgoño en Concón pic.twitter.com/7hjwotxhNr http://t.co/OYlLzxcdHC vía (@PeriodicoMirada)— La Tercera (@latercera) September 17, 2015
Costanera de Los Vilos con daños . pic.twitter.com/ntyrvEdnTQ— Luis Felipe Zúñiga (@lfelipezuniga) September 17, 2015
#Ahora El mar ya llegó a la Av. Borgoño en #Concón #Chile pic.twitter.com/NOV55wTlqu— MDZ online (@mdzonline) September 17, 2015
Imagen del patio de comidas del mall de La Serena. @christianpino @tvn_gonzalo pic.twitter.com/dzvHtgCFws— Rodrigo Vilches M. (@RodrigoVilchesM) September 17, 2015
Reportan más daños en #GodoyCruz [Foto vía @FranquitoMateos ] pic.twitter.com/whHTaiLxxB— MDZ online (@mdzonline) September 17, 2015
The mayor of the town of Illapel, Denis Cortés, reported one person was killed after a wall collapsed at the epicenter of 8,4 quake #Chile— Ignacio de los Reyes (@BBC_DelosReyes) September 17, 2015
A magnitude-8.8 quake and ensuing tsunami in central Chile in 2010 killed more than 500 people, destroyed 220,000 homes, and washed away docks and seaside resorts. That quake released so much energy, it actually it shortened the Earth's day by a fraction of a second by changing the planet's rotation rate.
Chile is one of the world's most earthquake-prone countries because just off the coast, the Nazca tectonic plate plunges beneath the South American plate, pushing the towering Andes Mountains to ever-higher altitudes.
[Video] Así se vivió el terremoto en una piscina de #Tunuyán Vía @Vickivillalobos pic.twitter.com/NNuj0zP12I— MDZ online (@mdzonline) September 16, 2015
According to the USGS, this quake occurred as the result of "thrust faulting on the interface between the Nazca and South America plates in Central Chile." Where the earthquake occurred, the Nazca plate is moving toward the east-northeast toward South America, and begins diving underneath the Peru-Chile Trench, 85 km, or 53 miles, to the west of the Sept. 16 earthquake.
"While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area," the USGS said in a statement.
Some information in this report was provided by The Associated Press.
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UPDATES
7:40 p.m. PT: More detail about tsunami advisories in Hawaii, California added.
8:15 p.m. PT: Death toll increased.
8:50 p.m. PT: Death toll increased.
9:45 p.m. PT: More detail about tsunami advisories in New Zealand, Fiji, French Polynesia and elsewhere.
10.30 p.m. PT: Statement from President Michelle Bachelet.