Somma-Vesuvian Ground Movements and the Water Supply of Pompeii and the Bay of Naples

Abstract

The reconstruction of Pompeii's water-supply system is currently the focus of much debate. This debate is fueled by complicated and growing archaeological evidence for the water system within the town as well as three different proposed configura tions of Pompeii's aqueduct. The new synthesis of archaeological evidence presented here reveals three successive phases of piped distribution. The first, Augustan phase was altered considerably in a second phase to keep it operating, albeit with reduced supply, in the town's last decades. At the time of the eruption of Somma-Vesuvius in 79 C.E., a wholly new, third phase was under construction. A new interpretation of the archaeological remains around Ponte Tirone shows that the water that supplied Pompeii's distribution system came from either the Aqua Augusta or Somma-Vesuvius, but probably not from the Abella aqueduct. In addition, there is evidence in Ponte Tirone for a minimum ground uplift of approximately 30 cm on the flanks of the volcano prior to the eruption and greater deflation afterward. This uplift reduced and then stopped water supply to towns around the Bay of Naples, but whether it affected Pompeii remains unclear. This analysis further develops a new method of reconstructing past vertical ground movements via their impact on shallow-gradient, gravity-powered water systems.* in t r o d u c t io n : t h e c u r r e n t d e b a t e o v e r t h e s o u r c e a n d e n d o f p o m p e ii's w a t e rd is t r ib u t io n sy st e mTwo lo n g -ru n n in g deb ates reg a rd in g P o m p eii's a q u e d u c t a n d lead-pipe distribution system co n c ern (1) th e w ater system 's source, a n d (2) its e n d . In particular, scholars disagree a b o u t th e source an d d ate o f th e first aqu ed u ctsup p lied w ater d istrib u ted th ro u g h o u t th e city, as well as th e status o f th e w ater system in th e last two decad es betw een th e 62 -6 4 C.E. ea rth q u a k e s* 1 a n d th e 79 C.E. eru p tio n o f Somma-Vesuvius.2 T h e th re e d iffe ren t sources p ro p o sed fo r th e system are discussed below. M ost scholars have a rg u e d fo r an A ugustan d ate fo r th e aq u ed u ct-su p p lied system, b u t som e scholars have posited th a t S am nite o r Sullan colonial systems p re c e d e d th e A ugustan o n e .3

Roman Builders Facing the Risk of Disaster: Coupling Archaeological and Geochemical Analyses on a Section of the ‘Aqua Augusta’ (the Roman Serino Aqueduct, Southern Italy)

“…The growth rates of PTC1 and MDA are thus on the low side of the reported growth rate for aqueduct deposits, but still within the range of the given values, making the 12‐year period plausible. If the northern channel was re‐elevated after damage caused by the ad 62–3 earthquake (as suggested by Keenan‐Jones ), then the 12‐year duration would correspond to an interval between the post‐earthquake rehabilitation and the ad 79 eruption of Vesuvius. In that case, the top of the concretion at Mura d’Arce would correspond to a period subsequent to the ad 79 eruption.…”

“…; Dessales ). In particular, the disconnection of properties in peripheral areas and some private buildings from the pipe system indicates an attempt to preserve water only for what was regarded by the Pompeian administration as the most important part of the city (Dessales ; Keenan‐Jones ).…”

“…; Lorenz et al . ; Keenan‐Jones ). The northern section is considered as being the oldest one, although a precise age is lacking.…”

“…There no evidence that water has circulated above this level. All these observations—damage, restoration and the low water level—point to disorders affecting the use of the northern channel (see also Sampaolo ; Cosimi ; Keenan‐Jones ).…”

Travertine-based estimates of the amount of water supplied by ancient Rome's Anio Novus aqueduct

“…68-74). The roughly 10% of the aqueduct water that supplied 591 public water fountains (Frontinus, De Aquis 78.3) allowed Rome's population to reach 600 thousand-1 million people during the first century AD (Hopkins, 1978;Morley, 1996). Hence, some have attempted to resolve controversies over Rome's population by reference to changes in the flow rate of the water supply system (e.g.…”