Historian Matias de la Mota Padilla, writing in his 1742 Historia del reino de Nueva Galicia en la América Septentrional, relates how,
On December 30, of the year 1567, several comets having given warning, an earthquake followed which ruined various churches. Already, on July 15, Lake Chapala had risen so much that it destroyed all the buildings in its village although, on account of divine providence, not a single person perished, not in Chapala, nor in the other places with the destruction of the churches.
It was not like this with the tremor that was experienced on December 27 of the following year, 1568, in which the church of Cocula collapsed, wretchedly taking Father Esteban de Fuente Obejuna, its founder. On the same day, the church in Tzacoalco [Zacoalco] fell, and sixty Indians perished, and with them also Father Hernando Pobre, who had founded it. Also so many birds were seen flying that they obscured the sun, so unusual that they provoked admiration in all who saw them.
Comparison of historical records such as this one suggests that the Chapala area of Jalisco was seismically active from 1564 to 1568. The largest earthquake, causing the collapse of many churches, houses and friaries, occurred on December 27, 1568. There were widespread reports of damage. The main chapel in Chapala was destroyed.
The pattern of damage suggests that this earthquake had a magnitude of about 7 on the Richter scale. According to one of the Geographic Accounts for the region, landslides dammed the Ameca river for three weeks, and when the river flow resumed, the water was “of a reddish color that made it impossible to drink for many days.” Large cracks appeared in the lowlands. The flow of natural springs was changed, and the level of Lake Zacoalco was altered.
The earthquake’s epicenter was close to the junction of three major rift valleys, each with its own parallel systems of faults. The first is occupied by Lake Chapala, the second follows the Tepic-Zacoalco depression, and the third includes Sayula and Colima. The movement is part of the gradual splitting of a large triangular block (on which sits Puerto Vallarta) away from the Mexican mainland. This will eventually result in the formation of a new island, a topic explored further in chapter 2 of Geo-Mexico: the geography and dynamics of modern Mexico.
[This post is an edited extract from Lake Chapala Through the Ages, an anthology of traveller’s tales]