The Thunder Under Guanajuato
In 1784, a mining city in Mexico was shaken by a month of thunder coming from underground, but the ground never shook.
What was reported
On the night of 9 January 1784, the people of Guanajuato, then one of the richest silver-mining cities in the world, heard a deep rumbling like distant thunder, coming from beneath their feet. It continued, day and night, for weeks, sometimes with loud booms.
Yet no earthquake was felt. Many people fled the city, and officials had to order them back to keep the mines going. The explorer Alexander von Humboldt later described the 'bramidos', the roars, of Guanajuato.
Explanations offered
Geologists suggest they may have been many small, shallow earthquakes too weak to feel but loud enough to hear, or movements in the old mines. No cause has been confirmed.
- When
- January–February 1784
- Where
- Guanajuato, Mexico
- Witnesses
- The people of Guanajuato
- Status
- Never explained
Famous cases are real, widely reported events. Each file sets out what witnesses said and the explanations that have been offered, without taking a side.
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