The National Seismological System yesterday published a special report on the earthquake that occurred on November 19, 2019 off the coast of Chiapas. Until the moment of the publication of the report, and of this note, a series of slight tremors, many of them imperceptible or very localized, has been crossing the seas of Chiapas.
The statement says verbatim:
On November 19, 2019, the National Seismological Service (SSN) reported an earthquake with magnitude 6.4 located on the coast of the state of Chiapas, near the border with Guatemala. The quake, which occurred at 10:27 p.m., was felt in Ciudad Hidalgo, Comalapa, Huixtla, San Cristobal, Villahermosa and even in some locations in the Isthmus of Tehuantepec. The coordinates of the epicenter are 13.76 ° latitude N and 93.35 ° longitude W and the depth is 9 km (Figure 1). Until 5 in the morning on November 20, 14 aftershocks had been recorded, the largest of them being 4.9.
This is the Tweet of the SSN where you can download the PDF format of the report.
It's good to know how the Seismic Alert System really works. Whether the alert sounds or not, in one place or another, is not due to failures, but to a selection protocol that allows the alert to be given where it is needed. In following Tweet is the explanation provided by the SSN itself: