Actually, the real cause was that Cuba just began sales of new cars.
The ‘quake was due to the foundations of Castro Communism being shaken. If Cuba had begun selling cars at world market prices, the ‘quake would have been so severe that many building would have collapsed.
“Cuba opens car market for first time since 1959, buyers face huge markups
Cuba has opened its new and used car market for the first time in half a century, allowing citizens to buy vehicles from the state without obtaining special permission. Vehicles with markups of 400 percent or more dashed the hopes of potential customers in the country in which the average monthly wage is $20.”
Most of those 50-model cars and trucks may be worth 5-10 times more than the purchased price.