The dip of the subducting slab is about 15° as defined by focal mechanisms and earthquake hypocenters.

Seismicity in this area is characterised by regular megathrust earthquakes along the plate interface.

This suggests that the 1787 rupture extended for about 450 km along the coast, providing an estimate of magnitude 8.6, based on scaling against other similar earthquakes.

[3] The tsunami triggered by the earthquake affected the Mexican Pacific coast for more than 500 km along the shores of Oaxaca, Guerrero and Chiapas.

[4] The maximum wave height has been estimated as 18.5 m, based on records of inundation and current elevations.