Excerpt from 1492 and all that!
On All Saints’ Day, 1 November 1755, Portugal and specifically Lisbon was hit by an earthquake with a magnitude of over 8.5. It happened out in the Atlantic some 200 km off Cape St Vincent along the Azores-Gibraltar Transform Fault.
This fault had relatively regular quakes, there had been eight in the 14th century, five in the 16th, three in the 17th and two earlier ones in the 18th. The most serious, prior to this event, was the one in 1531 that had destroyed some 1,500 homes around Lisbon.
This 1755 earthquake also devastated the Algarve region and hit the Moroccan coast recording a heavy loss of life there, but most of the accounts of the time focus on Lisbon.
Fires had broken out around the city and large fissures had opened, the people of Lisbon ran from their homes and sought safety by the open dock sides. Those at the dock noticed the sea recede and then they were engulfed in a tsunami that ran through the port and up the Tagus River.
Accounts vary but one credible version talked of Lisbon then having a population of 200,000 and that some 30,000 to 40,000 of these were killed by the event. The same source estimated the total loss of life in Morocco, Portugal and Spain as 40,000 to 50,000.
85% of Lisbon’s buildings were destroyed by the earthquake, the tsunami and subsequent fires. A new opera house, called the Phoenix, was burned to the ground – one case of a Phoenix sinking in to the ashes! It took a year to clear the debris, many of the dead were loaded on barges and buried at sea.
Occurring on an important religious festival and, at-a-stroke, destroying many of the churches, many theories emerged about it being some form of divine retribution. Philosophers too used the event to develop theories. This navel-gazing led to Portugal drawing back on its previous colonial ambitions.