Qualla: 1906 Ecuador–Colombia earthquake

1906 Ecuador–Colombia earthquake: Introduction

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Grundkarte Milenioscuro, Relief Alexrk2, CC BY-SA 3.0. The morning of Wednesday, January 31, 1906 was calm along the coast of Ecuador and southern Colombia - palm-lined shoreline, fishing boats, the slow coastal life of the Pacific tropics. At 10:36 local time, the sea floor off Esmeraldas gave way. A section of the North Andes plate boundary 500 to 600 kilometres long slipped in a single great rupture, releasing more seismic energy than all the major earthquakes of the following seventy years on that same coastline combined. The moment magnitude has been calculated at 8.8. It is one of the largest earthquakes ever measured instrumentally, and the tsunami it launched would still be recorded in Japan sixteen hours later.

Image: Grundkarte Milenioscuro, Relief Alexrk2 | CC BY-SA 3.0

1906 Ecuador–Colombia earthquake: Where Plates Collide

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Tisquesusa, CC BY 4.0. This coastline is one of the most seismically active on Earth for a specific geological reason. Offshore, the Pacific's Nazca plate - together with smaller fragments now known as the Malpelo and Coiba plates - slides eastward beneath the North Andes plate and the South American c...

Image: Tisquesusa | CC BY 4.0

1906 Ecuador–Colombia earthquake: The Wave on the Coast

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. What killed people was not the shaking. It was the water. Along the coastal strip from Río Verde in Ecuador to Micay in Colombia, the tsunami came ashore with little warning. Fishing villages built on low ground at river mouths were particularly exposed: the wave found its way up...

Image: Mikenorton | CC BY-SA 3.0

1906 Ecuador–Colombia earthquake: A Wave Across the Ocean

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. The 1906 tsunami did not stop at the Ecuadorian coast. Seismographs and tide gauges around the Pacific recorded the event. Wave heights were reported in Hawaii, Japan, and California, with runups modest enough in distant places to cause only minor local flooding but scientificall...

Image: Mikenorton | CC BY-SA 3.0

1906 Ecuador–Colombia earthquake: A Rupture That Came Back

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. The 1906 break did not release all the stress on that boundary; it just set the clock running again. Over the next century, the same segment ruptured in pieces. A magnitude 7.8 earthquake in 1942 broke part of it off Manabí Province. A 7.6 in 1958 broke another part near Esmerald...

Image: Mikenorton | CC BY-SA 3.0

1906 Ecuador–Colombia earthquake: The Long View

Sat, 18 Apr 2026 00:00:00 GMT

Photo credit Mikenorton, CC BY-SA 3.0. From our side of the twentieth century, the 1906 earthquake looks like a bookend - the great event that opened a century of smaller but still devastating quakes along a single plate boundary. For the residents of coastal Ecuador and Colombia in early 1906, it was a disaster, full...

Image: Mikenorton | CC BY-SA 3.0