By Liam Higgins
This week’s earthquakes near Guayaquil and Cuenca do not indicate an increase in seismic activity in southern Ecuador, according to the country’s Geophysical Institute (IG). “They were part of the ongoing process of tectonic plate movement that has occurred for millions of years and the overall number of earthquakes recorded recently is consistent with the historic average,” says institute geologist Jorge Coronel.
A Monday earthquake east of Guayaquil registered 5.8 on the Richter scale while a Tuesday morning quake northeast of Cuenca was 4.8 magnitude. No injuries or major damage was reported in either quake.
“We can’t forget that Ecuador is located on the “ring of fire” that encircles much of the Pacific Ocean,” Coronel says. “This is the margin at which movements of land masses collide and generate earthquakes. Within Ecuador there are areas that are more prone to major earthquakes and areas that are less prone and it is important that citizens be aware of the risk level in their location.”
The area at highest risk, according IG, is the coast. “This is the point at which the tectonic plates interact most directly and where the most intense earthquakes occur,” says Coronel. Ecuador’s strongest earthquake in historic time was centered near Esmeraldas in 1906 and was estimated to have had a magnitude of 8.8 to 9 on the Richter scale. The quake generated a tsunami that killed hundreds in Ecuador, Colombia, Hawaii and Japan.
Geologic records indicate that an even stronger quake occurred about 600 years ago just off-shore of present-day Salinas. Scientists estimate its strength at 9.5 to 9.8 and say that it sent a 100- to 200-foot wall of water inland across much of the south coast region.
The 2016 7.8 magnitude earthquake on the north coast was the most deadly and damaging in the last 50 years.
Ecuador’s Andean region is also subject to strong quakes, with Ibarra, Quito, Riobamba and Ambato suffering major damage in the 20th century earthquakes.
The southern Andes, including Cuenca and Loja, are in a less active seismic zone and are subject to fewer strong quakes. Cuenca, for example, has not suffered a major quake in the almost 500 years that records have been kept. Loja suffered one major earthquake about 400 years ago.
Coronel said that Tuesday morning’s 4.8 magnitude earthquake, centered 24 miles northeast of Cuenca, is probably a “good thing” for area residents. “It happened on the Giron fault, which runs through the town of Giron, south of Cuenca, and continues to the northeast,” he says. “The earthquake released pressure on the fault line, possibly indicating that it will be years before there is another rupture.”
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