You May Know of the Great Lisbon Earthquake of 1755. But Do You Know About the Quake and Tsunami That Day in Morocco?

The Great Lisbon Earthquake and fire of 1755 remains one of the iconic disasters of modern Europe; it devastated the Portuguese capital and sparked debates between religious folk who saw it as the judgment of an angry God (it occurred on All Saints Day, November 1), and Enlightenment philosophes who saw it as a sign of the arbitrariness of fate, most famously Voltaire, who subjects the eponymous hero of  Candide to it and makes him wonder if Pangloss is right about this being the best of all possible worlds. (Voltaire also wrote a separate essay on the earthquake.) Since I assume my readers are well-read, you probably know about the Great Lisbon Earthquake of November 1, 1755, but let me ask if you've heard of the destructive Tsunami that hit Morocco less than an hour later, and may have been as deadly there as in Portugal?

Though far from the deadliest earthquake by world standards, the 1755 shock, fire and Tsunami in Lisbon (the largest Tsunami on record for the North Atlantic) had a major impact in Europe, but many overlook the impact on Morocco.

The epicenter, as shown in the map at right from Wikipedia, was west of the Strait of Gibraltar; this is at a point where he Eurasian tectonic plate meets the African plate, though of course  plate tectonics were unknown  at the time. Although Lisbon's destruction is famous, the Algarve in southwestern Spain and Portugal and the coastal cities of Morocco may have suffered even worse from the quake itself and the resulting Tsunami, though Lisbon was in part destroyed by an accompanying fire. We know they were devastated, though casualty counts are slippery, in Morocco as in Portugal. Totals in the tens of thousands dead, however, are often cited for both sides of the Strait, with some going to six figures. But Voltaire didn't put Candide in Tangier or Rabat. Most estimates put the total dead in Morocco at at least 10,000, perhaps higher. The quake was also felt in Algiers.

Of course, the highly useful Japanese word tsunami was unknown in Europe in 1755; in Portuguese it was known as a maremoto, a movement of the sea.

While the earthquake is historically known as the Great Lisbon Earthquake, its effect, and that of the following tsunami, also took a toll on Spain and Morocco, particularly but not exclusively the coastal areas.

The sources for the Moroccan damage are scattered, including native Moroccan writers, Spanish and Portuguese priests living in those country's enclaves in Morocco, and European consuls. Because Morocco also suffered another earthquake wave the same month, November 18-19 centered in the Rif Mountains, some have argued (for example P.L.Blanc, cited below) that the reports of intense damage to the interior cities of Meknes (badly hit), Marrakech, and Fes may have conflated the November 1 earthquske with the later ones, but this is still debatable. Discussion and citation of these source can be found in online studies such as Evaluation du risque tsunamique sur la littoral Atlantique, a doctoral thesis by Samira Mellas in French; and  P.L. Blanc, "Earthquakes and tsunami in November 1755 in Morocco: a different reading of contemporaneous documentary sources."

Without studying each of the sources more carefully, I can't judge whether the damage from two separate quakes has been conflated, but in any event, both coastal and interior cities in Morocco suffered severe damage in November, 1755.

Along the coast, the Tsunami was devastating, though a reported height of 75 feet for the waves at El Jadida (then known by its Amazigh namd Mazagan or in Portuguese as Mazagão) is debated as being a likely exaggeration. Some reports claim that at Tangier the waves submerged the city walls. In Assila, the water entered the streets of the city, and along with the force of the earthquake, many houses were destroyed.

At the twin cities of Rabat and Salè, which face each other across the Bou Regreg River ships were sunk in he river and many drowned. Farther south at Safi there was also extensive damage. Agadir was also affected.

In the interior, there was certainly earthquake damage in Meknès, Marrakesh, and Fes; columns at the ancient Roman ruins of Volubilis also fell. Blanc argues that the damage in the interior was from the later November 18-19 quakes (the dates given by European reports; Mor0ccan reports date hem November 27-28). This is not established and reports written before those dates do refer to damage and deaths in the interior cities.

Casualty figures may be exaggerated (and the European ones distinguish between casualties among Christians, Jews, and "Moors," but certainly most accounts place the dead in multiple thousands. Though what made Lisbon so destructive was the combination of earthquake, Tsunami, and fire, the Moroccan accounts do not appear to speak of fire as a destructive force. Still, it seems clear that the Great Lisbon Earthquake was also the Great Moroccan earthquake.

Here's a modern simulation of the Tsunami: