The 62 Pompeii earthquake occurred on 5 February. It had an estimated magnitude of between 5 and 6 and a maximum intensity of XI or X on the Mercalli intensity scale

Mercalli intensity scale

The Mercalli intensity scale is a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude M_w usually reported for an earthquake , which is a measure of the energy released...

. The towns of Pompeii

Pompeii

The city of Pompeii is a partially buried Roman town-city near modern Naples in the Italian region of Campania, in the territory of the comune of Pompei. Along with Herculaneum, Pompeii was destroyed and completely buried during a long catastrophic eruption of the volcano Mount Vesuvius spanning...

 and Herculaneum

Herculaneum

Herculaneum was an ancient Roman town destroyed by volcanic pyroclastic flows in AD 79, located in the territory of the current commune of Ercolano, in the Italian region of Campania in the shadow of Mt...

 were severely damaged. The earthquake may have been a precursor to the eruption of Mount Vesuvius

Eruption of Mount Vesuvius in AD 79

In the year of AD 79, Mount Vesuvius erupted in one of the most catastrophic and famous eruptions of all time. The Roman vicinities of Pompeii, Herculaneum and Stabiae were affected, and Pompeii and Herculaneum were obliterated...

 in AD 79 that destroyed the same two towns. The contemporary philosopher and dramatist Seneca the Younger

Seneca the Younger

Lucius Annaeus Seneca was a Roman Stoic philosopher, statesman, dramatist, and in one work humorist, of the Silver Age of Latin literature. He was tutor and later advisor to emperor Nero...

, wrote an account of the earthquake in the sixth book of his Naturales quaestiones

Naturales quaestiones

Naturales quaestiones is an encyclopedia of the natural world written by Seneca around 65 AD. It is much shorter than the Naturalis Historia produced by Pliny the Elder some ten years later, however.-Content:...

entitled De Terrae Motu (Concerning Earthquakes).

Geological setting

The epicentre of the earthquake lies within a zone of active extensional faulting, but close to the southern flank of Vesuvius. Analysis of focal mechanism

Focal mechanism

The focal mechanism of an earthquake describes the inelastic deformation in the source region that generates the seismic waves. In the case of a fault-related event it refers to the orientation of the fault plane that slipped and the slip vector and is also known as a fault-plane solution...

s from the area around Vesuvius indicates that active faulting in the area involves NW-SE and NE-SW trending oblique-slip normal faults and E-W trending normal faults, part of the zone of active extension that extends the full length of the Apennines mountain chain, associated with continued opening of the Tyrrhenian Sea

Tyrrhenian Sea

The Tyrrhenian Sea is part of the Mediterranean Sea off the western coast of Italy.-Geography:The sea is bounded by Corsica and Sardinia , Tuscany, Lazio, Campania, Basilicata and Calabria and Sicily ....

. An association between earthquakes in the central Apennines and eruptions of Vesuvius has been proposed, but is not yet proven.

Characteristics

The extent of damage has been used to estimate the magnitude of the earthquake. Estimates lie in the range from about 5 to 6.1. The maximum felt intensity is estimated to be in the range IX to X, and the area of highest intensity is elongated roughly WNW-ESE. Shaking was reported to have continued for several days, presumably referring to a sequence of aftershock

Aftershock

An aftershock is a smaller earthquake that occurs after a previous large earthquake, in the same area of the main shock. If an aftershock is larger than the main shock, the aftershock is redesignated as the main shock and the original main shock is redesignated as a foreshock...

s. The focal

Hypocenter

The hypocenter refers to the site of an earthquake or a nuclear explosion...

 depth is estimated to be in the range 5–6 km.

Damage

The towns of Pompeii and Herculaneum both suffered major damage, with damage to some buildings also reported from Naples

Naples

Naples is a city in Southern Italy, situated on the country's west coast by the Gulf of Naples. Lying between two notable volcanic regions, Mount Vesuvius and the Phlegraean Fields, it is the capital of the region of Campania and of the province of Naples...

 and Nuceria

Nocera Inferiore

Nocera Inferiore, formerly Nocera dei Pagani, is a town and comune in Campania, Italy, in the province of Salerno, at the foot of Monte Albino, 20 km east-south-east of Naples by rail.-History:...

. Seneca reported the death of a flock of 600 sheep that he attributed to the effects of poison gases.

Aftermath

The damage caused by the mainshock and the subsequent series of tremors was at least partly repaired by the time of the AD 79 eruption in both Pompeii and Herculaneum. A pair of bas-reliefs, probably from the Lararium

Lares Familiares

Lares Familiares were household tutelary deities of ancient Roman religion. The singular form is Lar Familiaris....

, in the house of Lucius Caecilius Iucundus

Lucius Caecilius Iucundus

Lucius Caecilius Iucundus was a banker who lived in the Roman town of Pompeii around 20 - 62 AD. His house still stands and can be seen in the ruins of the city Pompeii. It was partially destroyed by the eruption of Vesuvius in 79...

 in Pompeii are interpreted to depict the effects of the earthquake on buildings including the Temple of Jupiter

Temple of Jupiter (Pompeii)

The Temple of Jupiter, Capitolium, or Temple of the Capitoline Triad was a temple in Roman Pompeii, at the north end of its forum...

and the Vesuvius Gate.

The earthquake led Roman philosopher, statesman and dramatist Seneca the younger to devote the sixth book of his Naturales quaestiones to the subject of earthquakes, describing the event of 5 February and giving the cause of earthquakes as the movement of air.