by Felice
Prager
Even people with only a little or no interest in science love watching television coverage of
erupting volcanoes.
Whether a volcano is of a destructive nature or a volcano is of a creative
nature, the awesome power overwhelms even the casual viewer. Most adult television viewers
can remember the dramatic footage of the lateral blast of the 1980 Mount St.
Helens eruption.
The destruction of the Wahaula Visitor Center in Hawaii Volcanoes National Park, the Royal
Gardens subdivision, and the village of Kalapana brought Hawaiian eruptions to the nation's
attention.
Footage from the 1991-1993 Etna eruption in Italy showed the successful diversion of
lava away from a village of frightened people.
The 1991 explosive eruption of Mount Pinatubo in the Philippines forced the evacuation of American
servicemen, their families, and thousands of Filipinos.
With the advent of
modern technology and communications, the media has managed to bring volcanic eruptions into our living rooms.
It was not always like that.
On November 8, 1963, about 130 meters below sea level, off the coast of Iceland (63.4N /
20.3W), a new island began to form due to a submarine volcano. There was little to no coverage of the event at the time.
Scientists followed it because scientists do that.
I knew about it because
my teacher had a boyfriend who was working in Iceland at the time, and he
sent us newspaper clippings and photographs of the event. I was in charge of
the bulletin board about it.
The eruptions of the submarine volcano became visible above the Atlantic Ocean on November 15, 1963. While Surtsey was forming, volcanic ash
and smoke shot up to 10 kilometers above the vent of the island.
Volcanic
ash clouds separate electrical charges just like vapor clouds so there were
many lightning storms during the creation of Surtsey.
During the first few
days, eruptions were not explosive and consisted of gentle effusions of
pillow lava. As the volcano grew towards sea level, the water pressure
decreased and activity became explosive.
The early phases of the eruption were caused by the interaction of magma and water
(phreatomagmatic.) Explosions were closely spaced or steady jets, producing dark clouds of
ash and steam shooting a hundred meters above the vent.
At times, a column of ash and
steam was carried 10 kilometers above the growing island. On January 31, 1964, activity shifted
400 meters to the northwest and eruptions continued at a new vent.
As the eruptions progressed, a new tuff ring developed that protected the vent from sea water.
On April 4, 1964, this caused the activity to change from phreatomagmatic explosions to lava
fountaining and lava flows.
Lava flows extended the island to the south and protected it
from wave erosion. This phase of the eruption ended on May 17, 1965. Surtsey
was quiet for more than a year.
On August 19, 1966, activity resumed at new vents on the east side of the island. More lava
flows moved to the south partially overlapping the older flows. The eruption stopped on June 5,
1967.
About one cubic kilometer of ash and lava had been produced with only 9% of it above sea
level.
It was not a huge surprise when Surtsey started to form because Iceland was also formed by
volcanic eruptions. Surtsey is part of the Vestmannaeyjar submarine volcano system which
also caused other famous eruptions at Heimaey.
Surtsey is now about 1.5 kilometers in diameter and has an area of 2.8 square kilometers.
Surtsey is 33 kilometers south of the main island of Iceland.
The island was named in 1965 by
the government of Iceland for Sutur, the fire god of Icelandic mythology.
Few submarine eruptions have been documented because of the difficulty in monitoring
submarine volcanoes.
