Ecuador earthquake: Death toll jumps to 272; more than 2500 injured

Ecuador Earthquake: Ecuador In State Of Emergency After Hundreds Killed

Ecuador Earthquake: Rescue workers work to pull out survivors trapped in a collapsed building after a huge earthquake struck, in the city of Manta early on April 17, 2016. (Credit: ARIEL OCHOA/AFP/Getty Images)

Yesterday Ecuador faced a catastrophic M7.8 earthquake, which claimed at least 238 lives and wounded thousands . Ecuador remains in a national state of emergency with widespread damage, lack of running water, and communication outages.

Ecuador earthquake of 7.8 magnitude kills dozens

The latest earthquake is the largest to hit Ecuador in decades, causing President Rafael Correa to curtail his trip to Europe short. Shaking could be felt well beyond Ecuador to as far north as Peru and Colombia. For comparison, the magnitude 7.8 earthquake yesterday in Ecuador was the same magnitude as the 1906 San Francisco earthquake that killed over 3,000 people and destroyed over three quarters of San Francisco.

The earthquake’s epicenter is located near Pedernales, a small fishing village with a population of 46,000. Reports indicate widespread damage to buildings, bridges, and roads in Ecuador’s Manabí province. The risk of a tsunami triggered from the earthquake has largely passed, according to the Pacific Tsunami Warning Center. Reports from the Ecuador government estimate that 1,550 people were injured, more than 370 buildings were destroyed, and another 151 buildings and 26 schools were affected.

Ecuador Earthquake Geologic Setting

The recent Ecuador earthquake was a result of a shallow thrust fault associated with the boundary of the Nazca and South American plate. The faulting is a result of the Nazca plate subducting (sliding beneath) the South American plate at an average rate 0f 61 mm per year. The subduction of the Nazca plate triggered the formation of the Andes mountain range and uplifted much of South America’s west coast. This same subduction caused the largest earthquake on record, a magnitude 9.5 occurring in southern Chile in 1960. Rapid subduction of the Nazca plate and subsequent uplifting of the Andes mountains has made the west coast of South America from Colombia to Chile one of the most active and destructive zones for earthquakes.

Ecuador earthquake map indicating the epicenter and the ShakeMap MMI contours. The earthquake was located at 0.371°N 79.940°W depth=19.2 km (11.9 mi) (Credit: USGS)

The majority of earthquakes in this region of South America fall within 0 to 70 km of the surface, what is considered to be a shallow earthquake. Unfortunately, shallow earthquakes tend to be much more common and dangerous. This is because the hypocenter, the point within the earth where strain is initially released and directly below the epicenter, in a shallow earthquake has less distance to dissipate. High magnitude deep earthquakes must travel a farther distance to reach the surface of the earth and thus the shaking and destruction tends to be dissipated and spread over a larger areal extent. The subduction of the Nazca plate underneath the South American plate is complex and segmented, often presenting difficulties in predictive earthquake monitoring.

Ecuador Earthquake: State of Emergency Declared

This earthquake came days after a pair of large earthquakes hit Japan of M6.5 and M7.0. The Japan earthquake of magnitude 7.0 claimed 41 lives and left widespread destruction of buildings. To compare the Japan earthquake vs. Ecuador earthquake it’s important to realize that the earthquake Richter magnitude scale is logarithmic. That means a 1 point increase in the scale results in 10 times the shaking amplitude. Therefore the Ecuador earthquake has a magnitude 0.8 larger than the Japan earthquake, resulting in 6 times larger magnitude on the seismogram and 15 times larger with respect to energy release.

A dozen earthquakes are associated with the main large M7.8 earthquake, all occurring within 24 hours of the primary earthquake. It is not uncommon to see swarming of earthquakes after a large earthquake. The initial release of strain then transfers to another region along the fault which causes smaller swarms of earthquakes.

Earthquakes in Ecuador within the last 24 hours of magnitude 2.5 or higher shows a swarm of 12 earthquakes associated with the primary earthquake. (Credit: USGS)

John Kerry, the United States Secretary of State offered his condolences and has said the U.S. is ready to support Ecuador in any way that we can. As of now, there are no reports of U.S. citizens killed during the earthquake.