Active normal faults accommodate the extension deformation, forming east–west trending horst and graben features.

[3] The 1899 earthquake was the result of rupturing an active normal fault in the West Anatolian Extensional Province.

A 50 km (31 mi) long surface rupture and up to 3 m (9.8 ft) of vertical displacement was measured during geological fieldworks in the 1960s and 1970s.

A 2013 study of damage and aid distribution reports led to the interpretation that the earthquake may have in fact been two mainshocks occurring in close succession of each other.

[4] The area within the Büyük Menderes Graben was extensively damaged, with the cities of Sultanhisar, Atca, Nazilli, Kuyucak, Sarayköy, Denizli and Karacasu experiencing the greatest destruction.

A total of 12,932 homes were destroyed, including 350 in Aydın; 2,052 in Köşk, Sultanhisar, Atça and Nazilli; 2,931 in Kuyucak and Ortakçı; and 720 in Sarayköy.

On the stretch of railroad from Aydin to Cal and Denizli, parts of the earthwork slumped, causing the rails to be suspended 2 m (6 ft 7 in) in the air.

Aid distribution was highly disorganized but carried on smoothly when official establishments in Aydın, Istanbul and İzmir were involved.