An earthquake is caused by the sudden movement of tectonic plates. The movement occurs when tectonic plates collide, split, or slide past each other. Earthquakes occasionally occur in volcanically active areas or along fault lines. Earthquakes occur on land and beneath the oceans. When tectonic movements occur beneath the ocean they result in an earthquake tsunami. A tsunami is a giant wave caused by a volcanic eruption or an earthquake under the sea. The effects are barely felt in the deep ocean but as the waves travel to the coastline they build up to higher heights. The 2017 Chiapas earthquake was the largest earthquake that year and triggered a tsunami known as the Mexico City Earthquake Tsunami.
The 2017 Chiapas Earthquake
On September 7, 2017, an earthquake struck the southern coast of Mexico at the wee hours of the night. The earthquake, which came to be known as the 2017 Chiapas earthquake, measured a magnitude of 8.2. Buildings in Mexico City trembled which caused people to evacuate. The earthquake generated a tsunami of 5 feet 9 inches above the tide level prompting authorities to issue a tsunami alert across the entire coast. It was the strongest earthquake in Mexico in the 19th and 20th century and the strongest earthquake recorded across the globe in 2017.
Warning and Signs
The earthquake’s epicenter was located at the Gulf of Tehuantepec. The gulf is located at the convergent boundary where the Cocos Plate is subducting below the North American Plate at the rate of 2.5 inches a year. A day before the earthquake, earthquake alarms in Mexico City were wrongly activated prompting buildings across the city to be evacuated.
The Earthquake Tsunami
The National Seismological Service of Mexico pinpointed the epicenter of the earthquake to the Gulf of Tehuantepec, 85 miles southeast of Tonala. The earthquake was caused by the faulting of the Cocos Plate when it subducted 33 feet below the North American plate. It was the most significant earthquake in the country since the 1985 earthquake that struck Mexico City. Mexican authorities claim that the earthquake was felt by more than 50 million people. According to seismologists and geophysicists, the quake relieved pressure that had built up in the faultline making future earthquakes less powerful. A tsunami alert was issued along the entire coastline as waves of up to 5.7 feet were reported in Chiapas. The alert was extended along the Pacific coast to Ecuador. Aftershocks were felt for the entire week with more than 1,800 measuring a magnitude of 6.1.
Over 1.5 million people were directly affected by the earthquake in Chiapas and more than 41,000 houses were damaged. About 98 lives were lost. A state of emergency was declared across 122 municipalities in the state of Chiapas followed by the deployment of the Mexican Army to aid in relief and recovery efforts. Hurricane Katia Made the situation even worse when it made landfall on the affected region.