[4] The site of Constantinople lies on the northern shore of the Sea of Marmara, which is a pull-apart basin related to active faulting on a series of segments of the North Anatolian Fault, the boundary between the Anatolian Plate and the Eurasian plate.

The fault zone accommodates approximately 24 mm per year of dextral (right lateral) displacement along this boundary and has been responsible for many destructive historical earthquakes, such as those in 1509 and 1766.

An earthquake in November 533 had led a crowd to seek refuge at the Forum of Constantine, but there were no real casualties.

He notes that it took place during the celebrations of the Brumalia (the Festival of Names), shortly before the winter solstice and the entry of the Sun to the sign of the Capricorn.

The air reportedly "grew dim with the vaporous exhalations of a smoky haze rising from an unknown source, and gleamed with a dull radiance".

Agathias observed that the city had precious few "wide open spaces entirely free of obstructions", which meant that residents were not safe from falling debris even outdoors.

[5] The district of Rhegium, close to the port of Constantinople, suffered the greatest loss of houses.

Agathias notes that "large numbers of ordinary people" perished, while Anatolius was the only casualty among the high-ranking in society.

The overjoyed people started seeking those nearest and dearest to them, "kissing and embracing and weeping with delight and surprise".