A 30-year-old legacy from the Cold War has surfaced on a remote
Alaskan island, where scientists and Aleutian natives are concerned that
radiation from the largest nuclear weapons blast ever conducted in America
could now be leaking into the marine environment.
At precisely 11 a.m. on Nov. 6, 1971, weapons specialists from the Atomic
Energy Commission exploded a 5-megaton bomb -- a prototype for a ballistic
missile warhead -- inside a mile-deep shaft drilled beneath Amchitka Island
only 87 miles from Petropavlovsk, Russia's Siberian naval base.
The thermonuclear blast was almost 400 times more powerful than the weapon
that destroyed Hiroshima. Code-named Cannikin, the weapon shattered the
shaft's walls and blasted a huge cavern lined with glasslike molten rock. It
triggered a rockfall of jagged boulders from a nearby cliff, created a mile-
wide crater atop ground zero that filled with water now known as Cannikin Lake,
uplifted a mile of the nearby ground by 20 feet, and vented groundwater
through cracks and old seismic faults throughout the site.
The blast was felt throughout Alaska, and it registered as a magnitude-7
earthquake recorded by seismographs around the world.
At the American Geophysical Union meeting in San Francisco last week, John
C. Eichelberger of the University of Alaska Geophysical Institute and his
colleagues reported evidence that tectonic forces moving deep beneath the
seabed have been splitting Amchitka apart and creating fresh underground
fissures in the island's rocky coast.
They voiced their growing concern that for 22 years neither the Energy
Department nor any other government agency has monitored Amchitka's foggy
rockbound coast or its nearby waters to learn whether radioactive elements
might be leaking from the island into the marine environment.
Thirty years ago, the phenomenon known as plate tectonics was virtually
unknown, so scientists did not realize that a vast slab of the Earth's crust
called the Pacific plate has been diving ponderously down beneath North
America's continental plate for millions upon millions of years, Eichelberger
DOWNWARD TO WESTWARD
Recent geophysical evidence shows that along the Aleutian island chain
where Amchitka lies, the downward motion -- called subduction -- has shifted
more into a westward-sliding motion of the Pacific Plate that has been tearing
the chain apart at a rate of about 2 centimeters -- more than three-quarters
of an inch -- a year.
As a result, Eichelberger said at the geophysics meeting, the Amchitka site
"was -- unknowingly at the time -- like having a nuclear test site right next
to the San Andreas fault."
Because the island itself may be splitting in the inexorable grip of the
tectonic forces, it is quite possible that new seismic faults and new fissures
in Amchitka's rocks have opened up around the Cannikin blast site, allowing
hazardous radioactive elements to escape into the sea around the island,
Five years ago, Greenpeace, the environmental activist organization, tested
the waters around the island and said its experts had found dangerous
plutonium there, as well as americium, a nuclear fission byproduct.
But they found no trace of tritium, the radioactive form of hydrogen, which
is the telltale sign of a hydrogen bomb blast's residue, and Alaskan
environmental watchdogs as well as the Department of Energy determined that
the radioactive pollution came from fallout from Chinese nuclear weapons tests
in the atmosphere.
RELYING ON COMPUTER MODELS
Energy Department experts have created computer models of the Cannikin
blast's aftermath and have concluded that radioactive elements from the
explosion are effectively contained within the cavity created by the test.
But the Departments of Energy and Defense have never monitored the waters
offshore from Amchitka, nor have they tested coastal rocks, kelp beds or
marine animals for radiation.
"Some computer models suggest that the Cannikin cavity could in fact leak,"
Eichelberger said in an interview. "So the questions remain: First, is there a
significant risk, and second, if there is, what should we do about it?"
After his group's presentation of the Amchitka issue, Eichelberger held an
informal evening meeting of experts to discuss the possibility of an
independent investigation. The session included several specialists from the
Lawrence Livermore National Laboratory.
David Smith, a Livermore nuclear chemist who has followed up on the weapons
test effects at the Nevada test site, agreed that the best science possible is
essential to ascertain the status of Amchitka today.
"Over the best 30 years," Eichelberger said, "the world of geophysics has
been literally turned upside down. Our knowledge of plate tectonics has become
solid, and our measurement techniques have vastly improved. This is not a call
to arms. It is a call to thinking."
ON-SITE STUDIES DEMANDED
Both the state of Alaska and its native organizations remain strongly
concerned about the Defense Department's failure to conduct an on-site
investigation of the radiation issue in Amchitka's marine environment,
according to Douglas H. Dasher, a specialist on radiation contaminants for the
Alaska Department of Environmental Conservation, who attended the geophysics
"The DOE likes to make computer models, but what's really happening out
there inside the fissures and faults on the island no one knows," Dasher said
in an interview.
Native members of the Aleutian/Pribiloff Islands Association rely on the
marine life of the islands for their living, and have long called for on-site
studies of the radiation issue at Amchitka.
According the Dasher, commercial fishermen -- including Americans, Japanese
and Russians -- work the waters of the Aleutian island chain. And the native
peoples regularly use "subsistance foods" -- the meat of stellar sea lions,
harbor seals and ptarmigan, as well as fish -- for a diet much healthier than
the fast-food chains that are encroaching on their traditional lifestyle.
"The DOE's models and risk assessments of the effects of Cannikin and the
other two nuclear tests of 30 years ago say there's essentially no risk of
radiation contamination," Dasher said. "But that doesn't provide much
confidence for the native populations up there, and like them, we say, 'How do
you really know?' We need actual hard facts, not just smoke and mirrors."
©2001 San Francisco Chronicle