The 1906 Ecuador–Colombia earthquake had a moment magnitude of 8.8.
It struck offshore near Esmeraldas, Ecuador, on January 31, 1906, along the convergent boundary where oceanic crust is forced beneath the northern Andes region. The earthquake was a major megathrust event, meaning a large section of a subduction-zone fault ruptured at once.
The seafloor movement generated a destructive tsunami that affected coastal Ecuador and Colombia. At least 500 people were reported killed on Colombia’s coast, while total casualties are often estimated at around 1,000. The event is one of the largest earthquakes recorded along the Ecuador–Colombia segment of the Pacific margin.
A common mix-up is confusing magnitude with intensity. Magnitude describes the energy released by the earthquake itself; intensity describes the shaking and damage at a particular location. The 8.8 figure refers to moment magnitude, the standard scale used for very large earthquakes.