Following an earthquake in 1969 , the site was damaged . The unstable accessways along the walls were reinforced in 1971 , along with repaving the foundations , filling of cracks along the parapets and the masonry ( to imitate the taipa removed from the site ) . This was extended in 1975 to include work along the western wall of the clocktower . Between 1982 and 1983 , the restoration of the adarves and battlements were undertaken , and continue the restoration of the walls and turrets . This turret was immediately reconstructed in 1985 in stone masonry , with imitation taipa . In successive years ( 1986 , 1987 and 1988 ) there were recovery works : reconstruction , improvement and consolidation of the walls and turrets
earthquake in 1969
1969 Portugal earthquake
Castle of Alcácer do Sal