|
2004 Denver Annual Meeting (November 7–10, 2004) |
|
|
Paper No. 127-3 |
|
|
Presentation Time: 8:30 AM-8:45 AM |
||
AVALANCHE-ASSOCIATED MASS FLOWS DAMAGED POMPEII SEVERAL TIMES BEFORE THE
VESUVIUS CATASTROPHIC ERUPTION IN THE 79 C.E
|
||
|
SENATORE, Maria
Rosaria1, STANLEY, Jean-Daniel2, and PESCATORE,
Tullio S.1, (1) Dipartimento di Studi Geologici e Ambientali,
Universita' degli Studi del Sannio, Via Port'Arsa, 11, Benevento, 82100,
Italy, senatore@unisannio.it, (2) Geoarchaeology Program, Smithsonian
Institution, Room E-205, NMNH, Washington, DC 20560 The ancient town of Pompeii, in southern Italy, is situated southeast of
Naples at the base of Somma-Vesuvius volcano. Historical data show that the
town had a discontinuous development until the I century B.C.E. and then
flourished until it was seriously damaged by powerful earthquake tremors in
62 C.E. While still under repair seventeen years later, Pompeii was destroyed
and completely buried by pyroclastic deposits from the catastrophic Vesuvius
eruption of 79 C.E. Mass-wasted deposits triggered by flood flows were discovered in and
around Pompeii under the 79 C.E. pyroclastic deposits. We associate the
discontinuous development of Pompeii with these sediment gravity flows that
damaged the city long before its final demise by the Vesuvius eruption.
Evidence for this, in new site excavations and drill cores, includes at least
three downslope-directed depositional episodes channeled via a now-buried
river valley that formerly extended to Pompeii. One such mass flow may have
been partially responsible for urban decline between the 5th and 3rd
centuries B.C.E. when climatic conditions in southern Italy were
characterized by cool-humid phases involving increased rain storms. Ancient gravity flows discovered here are similar to those recently
triggered by intense rains and that destroyed towns near Pompeii. On 5 May
1998 avalanche flows of water-saturated tephra-rich colluvium, including
boulders were released after about 30 hours of strong continuous rainfall
(100-180 mm) from the surrounding calcareous highlands, merged and moved
downslope at a rate of ~50 km/hour. The landslides evolved to
hyperconcentrated flows incorporating remobilized volcaniclastic sediment
with carbonate debris. These recent high-density mass flows killed more than
150 persons, destroyed numerous dwellings, and thickly blanketed the streets
of the town of Sarno, 14 km E of ancient Pompeii. Geoarchaeological study shows that the Gulf of Naples region, in the past
as at present, has been more susceptible to episodic damage from hydrological
hazards of avalanches and mass flows than to earthquakes and volcanism. |
|
|
|
2004 Denver
Annual Meeting (November 7–10, 2004) |
|
|