Earthquake scale / What is scale stone?

There are cylinder marble scales placed to four bores in two corners of mosques in Ottoman Architecture in order to detect whether mosque is harmed due to earthquake or landslide and there is any damage in building.

These marble cylinders are placed vertically into bores and if marble doesn’t rotate inside bore it means building is harmed.

For example marble scale of Yeşil Mosque opened to service in 1424 in Bursa as one of the important sample of Ottoman architecture still rotates.