The 2016 Ecuador earthquake occurred on April 16 at with a moment magnitude of 7.8 and a maximum Mercalli intensity of VIII (Severe). The very large thrust earthquake was centered approximately from the towns of Muisne and Pedernales in a sparsely populated part of the country, and from the capital Quito, where it was felt strongly. Regions of Manta, Pedernales and Portoviejo accounted for over 75 percent of total casualties. Manta's central commercial shopping district, Tarqui, was completely destroyed. Widespread damage was caused across Manabí Province, with structures hundreds of kilometres from the epicenter collapsing. At least 676 people were killed and 16,600 people injured. President Rafael Correa declared a state of emergency; 13,500 military personnel and police officers were dispatched for recovery operations.
Geology
Ecuador lies above the destructive plate boundary where the Nazca Plate is subducting beneath the South American Plate. The convergence rate between the plates in Ecuador is per year. The depth, location and focal mechanism of the earthquake are all consistent with rupture along the plate interface in the form of a megathrust earthquake. A major earthquake in 1906 ruptured the plate interface for at least 400 km immediately northeast of the 2016 event.
In this particular event, the plate boundary ruptured a 80 × 60 km2 area at a depth of between 15 and 44 km. The rupture failed to propagate towards the trench; ceasing about 60 km away. A maximum slip of 2.5 meters was estimated, while the average slip across the rupture was 0.7 meters.
The earthquake ruptured a part of the plate boundary that had previously ruptured in another magnitude 7.8 quake in 1942. The similar aftershock distribution and rupture characteristics suggest the 2016 event was a repeat of the earthquake in 1942. The 1942 earthquake marked the beginning of a supercycle of earthquakes re-rupturing the entire boundary previously broken during the large 1906 event. The last earthquake in the supercycle occurred in 1979. Another earthquake in 1958 also formed part of the supercycle.
Earthquake
At 18:58 ECT on April 16, a 7.8 Mw earthquake struck the coast of Ecuador approximately south-southeast of Muisne, in the province of Esmeraldas, at a depth of . Tremors were felt in neighboring Colombia and Peru; a clinic in Cali, Colombia, was evacuated as a precautionary measure. A tsunami alert was issued by the Pacific Tsunami Warning Center for Colombia, Costa Rica, Ecuador, Fiji, Panama, and Peru. This is the largest earthquake to strike Ecuador since the 1979 Tumaco earthquake. According to Mayor Gabriel Alcivar, much of the town of Pedernales, about 35 km to the south-southwest of the earthquake's epicenter, was leveled. In Guayaquil—approximately from the epicenter—an overpass collapsed on a car, killing the driver. In Manta the control tower of the airport was severely damaged; an Air Force officer was injured and the airport closed. Six homes collapsed and many others lost power in the nation's capital city of Quito.
The earthquake was presaged by a magnitude 4.8 foreshock eleven minutes before the main quake struck, and followed by over fifty-five aftershocks in the first twenty-four hours.
Casualties
At least 676 people were killed and more than 16,600 others were injured in the earthquake. It was the worst natural disaster to hit Ecuador since the 1949 Ambato earthquake. Over 300 fatalities occurred in the cities of Manta and Portoviejo, both of which are located in Manabí Province. President Rafael Correa stated that the reconstruction would cost "billions of dollars."
The number of fatalities was estimated as several hundred within thirty minutes of the earthquake. However, the media reported the number of fatalities as significantly lower than what actually happened and than what was estimated within thirty minutes as the figure of reported fatalities with time shows. The number of injuries reported by media also remained below the ultimate count and below the correct estimate within 30 minutes by QLARM as seen in the next figure.