The Mexican National Seismological Service (SSN) reported the quake’s epicenter to be some 20 kilometers north of Tesistan, in the municipality of Zapopan.
The quake struck at 10.09 a.m. and rattled buildings throughout Guadalajara. Workers at Zapopan city hall quickly moved into the huge Plaza de las Americas facing the Basilica. Meanwhile, various offices emptied in downtown Guadalajara.
Around 500 people, including doctors, nurses and patients, were evacuated from the Hospital General de Zapopan, better known as the Hospitalito.
Trinidad Lopez Rivas, chief of the Jalisco Civil Protection unit, mobilized emergency personnel but was quick to reassure citizens that the quake had caused virtually no damage, apart from a few minor fissures in a couple of buildings. No injuries were reported.
SSN officials later revealed that the quake occurred at a depth of ten kilometers – a major reason why it was only felt in Guadalajara and its suburbs.
An aftershock measured at 3.9 on the Richter Scale was registered at 11.50 p.m. Three further aftershocks occurred in the following hours.
According to SNN data, more earthquakes have occurred in Jalisco this year any other in the past decade. Around 140 have had a magnitude of more than 3.5, and 42 have been registered in November and December alone. Strikingly, only 44 measured higher than this level in 2014.
There seems to be no scientific explanation as to why so many more earthquakes have occurred this year. One possibility, however, could be more effective monitoring by the SSN, which now has 56 stations around the country.
There are approximately 6,000 earthquakes per year greater than magnitude 4.0 around the world, and hundreds of thousands of smaller earthquakes that mostly go undetected.