Earthquakes in Mallorca. II.
The most destructive struck in 1851, occurring along the Sineu-Sencelles fault, the main NE-SW fault of the Island reaching Palma, causing church spires to topple, collapsing the western fašade of the Cathedral and extending as far as the Island of Cabrera 22 km S of Palma Bay. There was considerable damage to the prison and convicts were evacuated to Manacor, where it had hardly been felt at all. Clocks stopped in the Tramuntana Range.
It was a seismic event that lasted seven months, with its epicentre around P˛rtol, sa Cabaneta and Santa EugŔnia. At least thirteen aftershocks were experienced in this area. Twenty days after the earthquake, the most severe of these completely demolished Sant Maršal Church in MarratxÝ.
As a result of the movements detected in the Algerian tectonic plates in 2003, the Spanish Government decided to include the Islands in the areas of moderate risk from earthquakes. The Balearic Government ordered six municipalities, Palma, MarratxÝ, Santa Maria del CamÝ, Esporles, Bunyola and Valldemossa to draw up contingency plans. The local government also recommended that 29 municipalities should do the same. Palma and MarratxÝ were of particular concern because of the high density of housing.