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streets; and moving a 3-ton statue 16 m. Accompanying
the blast was a swirling cloud of incandescent ash and gases
with an internal temperature of 700°C that incinerated
everything in its path. The nuée ardente passed through
St. Pierre in two or three minutes, only to be followed by
a fi restorm as combustible materials burned and casks of
rum exploded. But by then most of the 28,000 residents
of the city were already dead. In fact, in the area covered
by the nuée ardente, only two survived!* One survivor was
on the outer edge of the nuée ardente, but even there, he
was terribly burned and his family and neighbors were
all killed. The other survivor, a stevedore incarcerated the
night before for disorderly conduct, was in a windowless
cell partly below ground level. He remained in his cell badly
burned for four days after the eruption until rescue work-
ers heard his cries for help. He later became an attraction
in the Barnum and Bailey Circus where he was advertised
as “The only living object that survived in the 'Silent City
of Death' where 40,000 beings were suffocated, burned or
buried by one belching blast of Mont Pelée's terrible volca-
nic eruption.”**
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Figure 5.12
Nuée Ardente
a
St. Pierre, Martinique, after it was destroyed by a nuée
ardente from Mount Pelée in 1902. Only 2 of the city's 28,000
inhabitants survived.
Geologists have no formal defi nition for
supervolcano erup-
tions
, but we can take it to mean an explosive eruption of
hundreds of cubic kilometers of pyroclastic materials and
the origin of a huge caldera. No supervolcano eruptions
have occurred in historic times, but geologists know of sev-
eral that took place during the past two million years—Long
Valley in eastern Califormia, Toba in Indonesia, and Taupo
in New Zealand, for example.
On three occasions, supervolcano eruptions followed
the accumulation of rhyolitic magma beneath Yellowstone
National Park, which is mostly in Wyoming, each yielding a
widespread blanket of volcanic ash and pumice and gigantic
calderas. We can summarize Yellowstone's volcanic history by
noting that supervolcano eruptions took place 2 million years
ago, 1.3 million years ago, and 600,000 years ago. Then, be-
tween 150,000 and 75,000 years ago, an additional 1000 km
3
of pyroclastic materials were erupted within the Yellowstone
caldera (
Figure 5.13).
Geologists think that these huge eruptions were caused
by a rising mantle plume, a cylindrical mass of magma prob-
ably of rhyolitic composition. Because this type of magma is
viscous, it triggers explosive eruptions when it nears the sur-
face. Personnel from the U.S. Geological Survey (USGS) and
the University of Utah continue to monitor the Yellowstone
area for any signs of renewed activity.
◗
b
An April 1986 pyroclastic fl ow rushing down Augustine volcano
in Alaska. This fl ow is similar to the one that wiped out St. Pierre.
* Although reports commonly claim that only two people survived the
eruption, at least 69 and possibly as many as 111 people survived beyond
the extreme margins of the nuée ardente and on ships in the harbor.
Many, however, were badly injured.
**Quoted from A. Scarth, Vulcan's Fury: Man Against the Volcano
(New Haven, CT: Yale University Press, 1999), p. 177.
fl ow followed a valley to the sea, but the nuée ardente jumped a
ridge and engulfed the city of St. Pierre (
Figure 5.12).
A tremendous blast hit St. Pierre, leveling buildings;
hurling boulders, trees, and pieces of masonry down the
◗
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