Pompeii

Warning signs?

Campania earthquake (62 CE)

• Bay of Naples

• 5.6 Richter

• 9+ Moment Magnitude

Pyroclastic Density Current

• Ash column collapses, extremely hot ash/rock/debris form fast-moving avalanche

• Kills the most in Pompeii

• Destroys Herculaneum (Day 1 of Eruption) — most of the 340 bodies were found in boat sheds along the shore

  • evidence of less pumice but more thermal trauma

  • original population was 5,000: how many people fled?

* makes tuff: found in lots of ancient construction

Events + Days

Day 1

• Several feet of pumice rain down and collapse roofs

  • Very few people killed from this — others decide shelter (bodies found in interior spaces) or flee (near gates)

• Tremors intensify, electromagnetic clouds & thunder

Day 2

• PDC reaches Pompeii and suffocates remaining people

  • First white pumice, then gray pumice → indicates increasing lithic content + instability of the volcanic column

Stratigraphy + Phases of the Eruption

• Convective column → multiple PDCs

  • Ash falls: deposits of airborne, pulverized rock

  • Ash flows: PDCs

• Lahar deposits: poorly sorted water, volcanic ash, and debris flow down the volcano like concrete + move along valleys/low areas (i.e. slow flow)

• Lapilli fall deposits: well sorted rock falls with distance from the eruption

• Lithic layers: composition shifts dramatically

• Phreatomagmatic Eruption: water interacts with ash as the column collapses in on itself and aquifers make a new eruption — secondary material re-use phase which lasts many days

  • creates finer grained ash layers

Archaeological Evidence: Eumakia

Wall facade of this building re-constructed using Opus Latericeum style (brick-faced concrete), which survived lateral shaking better than the original large stone block construction

Archaeological Evidence: Stabian Baths

In the middle of re-construction from 62 CE when 79 CE earthquake hit

Structural Integrity Examples

1. Basilica and Amphitheaters: pumice did the most damage, PDC came after

   • Roofs collapse first + fill the structures with pumice

2. Multi-level structures: survive better because they don’t collapse as easily

   • PDC preserves more here, like bodies + papyrus

Archaeological Evidence: Palaestra

Many bodies found here — social meeting place, so people perhaps came to plan next steps

• evidence of organized escape instead of panic

Fugitive Garden

Right inside the main gate — several bodies found here overcome by the PDC

• Above lapilli deposit layer, inside of the pumice layer

Excavation

Amedeo Maiuri was the first to do a systematic excavation below the pumice layer