The USGS initially calculated the quake’s magnitude at 7.5, but later downgraded it to 7.2. It said the quake was centered 22 miles northwest of the town of Tecpan de Galeana, and was 15 miles deep.
In many cases of earthquakes in Mexico, it can take time to receive word from remote areas near the epicenter, where damage could be more extensive. There were no early reports of serious damage or injuries near the epicenter in Tecpan de Galeana.
Yesterday’s quake occurred along a section of the Pacific Coast known as the Guerrero Seismic Gap, a 125-mile section where tectonic plates meet and have been locked, meaning huge amounts of energy are being stored up with potentially devastating effects, said USGS seismologist Gavin Hayes.
The last large quake that occurred along the section was a magnitude-7.6 temblor in 1911, Hayes said.
He said scientists will be watching the area more intensely because moderate quakes such as yesterday’s can destabilize the surrounding sections of seismic plate and increase the chance of a more powerful temblor.
The USGS says the Guerrero Gap has the potential to produce a quake as strong as magnitude 8.4, potentially much more powerful than the magnitude-8.1 quake that killed 9,500 people and devastated large sections of Mexico City in 1985.
Mexico City itself is vulnerable even to distant earthquakes because much of it sits atop the muddy sediments of drained lake beds that quiver as quake waves hit.
The 1985 quake was centered 250 miles from the capital on the Pacific Coast.