Castle of Kruje, Albania, Dollma Tekke, after earthquake survey, December 2019

Earthquake 2019 On 26 November 2019, a strong earthquake struck the Albanian coast, with a seismic centre near Durres at 41.38° North and 19.45° East, with a main seismic hit at the eighth Mercalli's scale. It was one of the strongest earthquakes that occurred in recent years in Albania. The event caused 51 deaths in the population and produced heavy damage. 111 cultural monuments and heritage sites were assessed in the affected regions. Out of these, 53 were deemed unsafe or temporarily closed due to serious risk. Major landmarks such as the Castles of Durrës, Kruja, and Prezë sustained considerable structural damage. The seismic event exerted a pronounced impact on the built environment of Durrës and adjacent settlements, while considerable structural damage was also observed extending into the Tirana region. Digital Survey intervention The survey operated on the Dollma Tekke was not the first one from the same operative unit. In fact, an early intervention, with a full survey of the inner surface of the dome, was done in 2017. It was not due to any specific urgency, research or project; it was just an intervention aimed to create a specific documentation on a built heritage element appearing as worthy of attention. It was seen in some social posts during that same year, and so a visit and a photogrammetry survey were planned and done. The survey work was done by photogrammetry, using a Nikon D800e, a full-frame camera with a 36.3 Mp sensor, mounting a Nikkor zoom AF 24-120mm F4 set at 24mm. The shooting work was limited to the interiors, producing a series of 135 shots, then processed in Agisoft Photoscan 1.2 to produce a polygonal mesh of about 764 thousand faces. This early intervention turned out to be extremely valuable during the second survey.