1590 Neulengbach earthquake

Contemporary illustration of the damage in Vienna
Vienna
Date	15 September 1590 (1590-09-15)
Magnitude	5.5–6.0
Epicenter	48°18′N 15°30′E / 48.3°N 15.5°E / 48.3; 15.5Coordinates: 48°18′N 15°30′E / 48.3°N 15.5°E / 48.3; 15.5
Type	Unknown
Total damage	Severe
Max. intensity	VII–IX
Casualties	Unknown

The Neulengbach earthquake of 1590 occurred on 15 September shortly before midnight amidst a long series of much weaker seismic activity starting on 29 June and with aftershocks reported until 12 November. It was the strongest historically documented earthquake in what today is Northeastern Austria.

The epicenter is believed to have been located southeast of Neulengbach, about 30–40 km west of Vienna, in a flat dipping and North-South striking thrust fault that is part of the Vienna Transform fault zone. This moderately-active fault system extends over a distance of some 300 km from the Northern Limestone Alps through the Vienna Basin into the West Carpathian Mountains. The temblor's energy release is estimated at 5.5–6.0 on the Richter magnitude scale and it had class VII intensity on the modified Mercalli intensity scale in most of Lower Austria.

Significant destruction occurred in Vienna, which at this time had about 50,000 inhabitants living within a fortified and densely urban area that covered what today is the innermost city center. The upper half of St. Michael's church tower collapsed in spite of its steel reinforcements, the Scottish Abbey was severely damaged, and the Southern tower of St. Stephen's Cathedral suffered as well. At this time it was not customary to document damage to property that did not serve sacral purposes or was directly used by the aristocracy, and very little information has survived concerning the destruction and harm inflicted on ordinary citizens. Therefore, the fact that the death of nine people in a collapsing traveller's hostel was specifically mentioned in the chronicles suggests that the number of urban casualties cannot have been significant.

At Zwentendorf, 40 km to the North of the presumed epicenter, the local parish church was so heavily damaged that it became unusable. (Exposure of this particular area to seismic risk played a significant role in the public debate that erupted in the 1970s concerning plans for a nuclear power plant near Zwentendorf.) Vaults and roofs collapsed at the Mauerbach Charterhouse West of Vienna, and many fortifications in Lower Austria (e.g., at Sieghartskirchen and Altlengbach) needed substantial repair.