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Geology
Thessaloniki lies on the northern fringe of the Thermaic Gulf on its eastern coast and is bound by Mount Chortiatis on its southeast. Its proximity to imposing mountain ranges, hills and fault lines, especially towards its southeast have historically made the city prone to geological changes.
Since medieval times, Thessaloniki has been hit by strong earthquakes, notably in 1759, 1902, 1978 and 1995. On 19–20 June 1978, the city suffered a series of powerful earthquakes, registering 5.5 and 6.5 on the Richter scale. The tremors caused considerable damage to a number of buildings and ancient monuments, but the city withstood the catastrophe without any major problems. One apartment building in central Thessaloniki collapsed during the second earthquake, killing many and raising the final death toll to 51.
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