II
DEMONS OF THE DEEP
"The Great Waves"
If the earth were smooth, all the land
areas would be covered by seawater to a depth of some 8,810 feet or one and
two-thirds miles.
Ninety percent of the earth's oceans are
more than two miles deep and the area of the earth covered by the sea is
estimated to be 139,670,000 square mites. This represents 70.92% of the total
surface.
The volume of earth's oceans is estimated
to be 308,400,000 cubic miles. And in most of these vast amounts of water occur
deadly waves of various types in a number of forms to become "Demons of the
Deep."
Seismic waves, commonly known as
tsunamis, result from the following causes (1) an up thrusting and/or down
thrusting of the sea bed where the earth's crust is unstable, producing a high
magnitude earthquake; (2) a major undersea landslide; (3) a submarine volcanic
eruption" or earthquake.
Hurricane waves occur when the low
pressure in the eye sucks up the sea beneath, raising it as much as 20 feet. At
the same time, violent winds whip up waves as tall as houses. The high water
level and rogue waves combine to make storm surges towering walls of seawater
that surge inland, sweeping away everything in their path.
Whirlpools
are caused when ocean currents, tidal flows, winds and irregularities in the
coastline and ocean floor combine to form a swirling mass of water. Twisting
vortexes capable of sucking boats down beneath the sea surface are rare only
found near coasts, not in open seas.
Rogue waves arise in turbulent
waters where winds and currents collide from many directions at once. Rogue
waves combine in nonlinear ways to form freak amplitudes of amazing height and
power.
The Greatest Wave Ever Recorded
On July 9, 1958, a monstrous wave developed
as the result of a swash, a type of tsunami, in Alaska's Lituya Bay. Lituya Bay
is shaped somewhat like a frying pan with a narrow entrance on the southeastern
coast of Alaska. An earthquake in the bay dislodged some 90,000,000 tons of rock
and earth from hills around Gilbert Inlet, at the head of the bay, from heights
of 3,000 feet.
The occurrence has been described as
"equivalent to the simultaneous launching of 2,000 battleships from a
slipway half a mile high." The result was incredible, producing a tsunami
that raced across the bay with a wave that reached a height of 100 feet and up
to 1,700 feet as evidenced by the damage marks on the hills it struck. A monster
wave a third of a mile high! The unpopulated area was heavily forested, but
after the wave retreated four square miles of forest had disappeared.