EARTHQUAKES, TSUNAMIS AND FIRES
The first signs of trouble are partial repairs and the absence of repairs after earthquakes, tsunamis and fires. From texts and inscriptions we know that Ostia and Portus were struck by natural disasters already in the republican period. In 44 BC a portent is mentioned that is related to a tsunami: "In Ostia a shoal of fish was left on dry land by the retracting of the sea". In 62 AD as much as 200 ships perished in the harbour of Claudius during "a violent storm", in view of the scale more likely a tsunami (in the same year Pompeii was struck by an earthquake). And in 196 AD Septimius Severus "restored a column broken by the force of a storm", in Portus.
The first archaeological evidence of such natural disasters belongs to the third century AD. When beams of ceilings rot away, or when a building is destroyed by a fire, the walls tend to fall inward. When an earthquake occurs, walls tend to fall outward. An earthquake may cause irregular, vertical cracks in the walls. The underground wave of an earthquake may push a wall upward. The upper part may then become detached, and when it lands on the lower part, it will stick out a few centimeters. There may also be torsion, a twisting of the upper part.
In Portus the excavators saw traces of several earthquakes and tsunamis in the third and fourth century. In a cistern in Portus corpses were found below deposits resulting from a tsunami, perhaps combined with an earthquake. On the corpses coins were found from 236 and 238 AD.[1] Work near the coast to the south of Ostia, in 238 AD, may be related. In that year Maximinus Augustus and Maximus Caesar repaired the road leading from Ostia to Antium after it had been damaged by the sea.[2] The first building in Ostia of which we know that it ceased to function are the Baths of the Swimmer (V,X,3). An accurate excavation has shown that it was abandoned in the years 240-250 AD. The date suggests a relation with the same seismic activity, apparently in 238 AD.
The House of the Priestesses (III,IX,6), part of the Garden Houses, was destroyed in the last quarter of the third century, witness coins from the reigns of Gallienus (253-268) and Aurelianus (270-275). The ceiling of the ground floor and the upper stories had collapsed. Traces of fire are not reported. The ruins were not cleared in antiquity. The House of the Millstones (I,III,1) was destroyed by a fire at the end of the third century, witness coins, the latest of which belong to the reign of Probus (276-282). The ruins were again not cleared. A very large number of coins was found in the adjacent House of Diana (I,III,3-4), a series also ending during the reign of Probus. In this building no traces of fire were seen, but the building to the north, the House of the Mithraeum of Menander (I,III,5), seems to have burned down. Michael Heinzelmann has noted that a very large suburban villa near the beach was destroyed by an earthquake at the end of the third century. The earthquake was deduced from the fact that collapsed walls and ceilings were found directly on the floor, not on a layer of debris. In rooms along the Via del Sabazeo many traces of a fire were found, on top of coins from the second and third century.
The destruction of all these buildings may well be related to one or two earthquakes, and perhaps tsunamis, around 275 AD and during the reign of Probus (276-282 AD) or a little later. As to the earthquake in 275, the Historia Augusta tells us about the Emperor Tacitus (275-276 AD) that among the omens predicting his death was this: "All the gods in their private chapel fell down, overthrown either by an earthquake or by some mischance". A gift to Ostia by the same Emperor might be related: "To the people of Ostia he presented from his own funds one hundred columns of Numidian marble, each twenty-three feet in height".
Heinzelmann reports that a luxurious house near the so-called Imperiale Palace was destroyed by an earthquake in late antiquity. A small harbour in the north-west part of the city was struck by a tsunami in the third quarter of the fourth century. Here we may think of the major earthquake of 346 AD, about which Hieronymus says: "For three days and three nights Rome was shaken and numerous towns in Campania were struck".[3] There was a smaller one in 375 AD.
A facade that collapsed and fell on Via del Tempio Rotondo, presumably during an earthquake, in the third or fourth century.
The facade belongs to the House on Via del Tempio Rotondo (IV,IV,7) and is still lying on the street.
Photo: Archivio Fotografico Ostia, neg. B 3082.
A room with kneading machines for dough, in bakery House of the Millstones (I,III,1).
After a devastating fire, the machines were not extracted from the building.
Photo: Archivio Fotografico Ostia, neg. B 2201.
A crack resulting from an earthquake in the House of Hercules (IV,II,2-4).
Typical earthquake damage in the House of Hercules (IV,II,2-4).
The upper part of the wall is sticking out a few centimeters.
Another example of earthquake damage.
Twisting of a pier in the Small Market (I,VIII,1).
(1) Scrinari 1984, 218; 1987, 182.
(2) CIL X, 6811.
(3) F. Galadini - P. Galli, "The 346 A.D. earthquake (Central-Southern Italy): an archaeoseismological approach", Annals of Geophysics 47, 2/3 (2004), 885-905.