October 25, 989 Earthquake: Istanbul (Constantinople), Turkey

989 Oct 25. A destructive earthquake in the eastern part of the Sea of Marmara caused extensive damage to villages and towns in the provinces of Thrace and Bithynia. In Constantinople many houses collapsed and public buildings and parts of the city walls were damaged or destroyed. Damage was equally heavy in Nicomedia(Izmit) and was in places aggravated by a seismic sea-wave(?). The shock was possibly felt as far as southern Greece. (reference #14000)

989 Oct 26. A destructive earthquake in the eastern part of the Sea of Marmara caused extensive damage to villages and towns in the provinces of Thrace and Bithynia. In Constantinople damage was serious. Many houses, churches and towers collapsed, killing those inside. The dome of the Hagia Sophia was affected and the western apse fell in and a crack appeared in one of the supporting walls. Repairs to the church alone, carried out under the emperor Basil II, took six years to complete and cost ten centenaria of gold, most of which seems to have been spent on cranes for the builders. The Valentinian aqueduct was reportedly damaged and collapsed in part, but was later rebuilt. Inscriptions on the tower at the junction of the land walls with the defences along the Sea of Marmara, and on the northern gateway tower of Pege, record the repairs carried out after the earthquake. The shock totally destroyed villages in the vicinity of Constantinople, killing a large number of people. Damage extended west of Constantinople and to Nicomedea, but details about this area are lacking. Waves flooded the coast and parts of Constantinople itself, with the sea advancing inland in places causing some additional damage, while offshore the waves destroyed the tower of Eutropius (Kiz Adasi) near the coast of Chalcedon, killing the monk who lived there. It is very likely that these waves were due to the heavy storms in the Sea of Marmara, which preceded and followed the event, rather than to the earthquake. (reference #9116)