|
|
 |
100 Amazing Earth Facts |
 |
 |
 |
41. What is
the largest lake
in the world? |
 |
|
|
By size and volume it is the
Caspian Sea, located between
southeast Europe and west
Asia. |
|
|
42. Where do
most earthquakes
and volcanic
eruptions occur
on Earth? |
|
|
 The majority occur along
boundaries of the dozen or
so major plates that more or
less float on the surface of
Earth. One of the most
active plate boundaries
where earthquakes and
eruptions are frequent, for
example, is around the
massive Pacific Plate
commonly referred to as the
Pacific Ring of Fire. It
fuels shaking and baking
from Japan to Alaska to
South America. |
|
|
43. How hot
are the planet's
innards? |
|
|
|
The temperature of Earth
increases about 36 degrees
Fahrenheit (20 degrees
Celsius) for every kilometer
(about 0.62 miles) you go
down. Near the center, its
thought to be at least 7,000
degrees Fahrenheit (3,870
Celsius). |
|
|
44. What
three countries
have the
greatest number
of historically
active
volcanoes? |
|
|
|
The top three countries are
Indonesia, Japan, and the
United States in descending
order of activity. |
|
|
45. How many
people worldwide
are at risk from
volcanoes? |
|
|
|
As of the year 2000, USGS
scientists estimated that
volcanoes posed a tangible
risk to at least 500 million
people. This is comparable
to the entire population of
the world at the beginning
of the seventeenth century! |
|
|
46.
Which of the
following
sources stores
the greatest
volume of fresh
water worldwide:
lakes, streams
or ground water? |
|
|
|
Groundwater comprises a 30
times greater volume than
all freshwater lakes, and
more than 3,000 times what's
in the world's streams and
rivers at any given time.
Groundwater is housed in
natural underground
aquifers, in which the water
typically runs around and
through the stone and other
material. |
|
|
47.
Which earthquake
was larger? |
|
|
|
The Anchorage earthquake had
a magnitude of 9.2, whereas
the San Francisco earthquake
was a magnitude 7.8. This
difference in magnitude
equates to 125 times more
energy being released in the
1964 quake and accounts for
why the Anchorage earthquake
was felt over an area of
almost 500,000 square miles
(1,295,000 square
kilometers). |
|
|
48.
Which earthquake
was more
destructive? |
|
|
|
The 1906 San Francisco
earthquake tops this
category. It was responsible
for 700 deaths versus 114
from the Anchorage
earthquake. Property damage
in San Francisco was also
greater in relative terms
due to the destructive fires
that destroyed mostly wooden
structures of the time. |
|
|
49. Is
Earth's core
solid? |
|
|
 The inner portion of the
core is thought to be solid.
But the outer portion of the
core appears molten. We've
never been there though, so
scientists aren't sure of
the exact composition. A
radical
Hollywood-like idea was recently put forth to
blow a crack in the planet
and send a probe down there
to learn more. An
interesting bit of recent
evidence shows Mars' core
may be similarly squishy.
Scientists figured this out
by studying tides on Mars (tides
on Mars?). |
|
|
50. Does all
of Earth spin at
the same rate? |
|
|
|
The solid inner core -- a
mass of iron comparable to
the size of the Moon --
spins faster than the outer
portion of the iron core,
which is liquid. A study in
1996 showed that over the
previous century, the extra
speed caused the inner core
to gain a quarter-turn on
the planet as a whole. So
the inner core makes a
complete revolution with
respect to the rest of Earth
in about 400 years. Immense
pressure keeps it solid. |
|
|
51.
How many people
have been killed
by volcanoes
during the last
500 years? |
|
|
|
At least 300,000. Between
1980 and 1990, volcanic
activity killed at least
26,000 people. |
|
|
52.
How much of the
Earth's surface
consists of
volcanic rock? |
|
|
|
Scientists estimate that
more than three-quarters of
Earth's surface is of
volcanic origin-- that is,
rocks either erupted by
volcanoes or molten rock
that cooled below ground and
has subsequently been
exposed at the surface. Most
of Earth's volcanic rocks
are found on the sea floor. |
|
|
53.
Can an
earthquake cause
a tsunami? |
|
|
|
If the earthquake originates
under the ocean, yes. Near
the earthquake's epicenter,
the sea floor rises and
falls, pushing all the water
above it up and down. This
motion produces a wave that
travels outward in all
directions. A tsunami can be
massive but remain
relatively low in height in
deep water. Upon nearing the
shore, it is forced up and
can reach the height of tall
buildings. One in 1964 was
triggered in Alaska and
swamped the small northern
California town of Crescent
City, moving train cars
several blocks and killing
several people there.
Asteroids can
cause tsunami,
too. |
|
|
54.
Are all tsunamis
high waves when
they strike a
coastline? |
|
|
|
No, contrary to many
artistic images of tsunamis,
most do not result in giant
breaking waves. Rather, most
tsunamis come onshore more
like very strong and fast
tides. The water can rise
higher than anyone along a
given shore area has ever
seen, however. |
|
|
55.
How much of the
Earth's land
surface is
desert? |
|
|
|
About one-third. |
|
|
56.
What's the
deepest place in
the ocean? |
|
|
 The greatest known depth is
36,198 feet (6.9 miles or 11
kilometers) at the Mariana
Trench, in the Pacific Ocean
well south of Japan near the
Mariana Islands. |
|
|
57.
What is the
fastest surface
wind ever
recorded? |
|
|
|
The fastest "regular" wind
that's widely agreed upon
was 231 mph (372 kph),
recorded at Mount
Washington, New Hampshire,
on April 12, 1934. But
during a May 1999 tornado in
Oklahoma, researchers
clocked the wind at 318 mph
(513 kph). For comparison,
Neptune's winds can rage to
900 mph (1,448 kph). |
|
|
58.
How much fresh
water is stored
in the Earth? |
|
|
|
More than two million cubic
miles of fresh water is
stored in the planet, nearly
half of it within a
half-mile of the surface.
Mars, too, appears to have a
lot of water near its surface, but what's
been detected so far is
locked up as ice; nobody has
estimated how much might be
there. |
|
|
59.
How old is
Earth? |
|
|
|
Our planet is more than 4.5
billion years old, just a
shade younger than the Sun.
Recent
evidence actually shows that Earth
was formed much earlier than
previously believed, just 10
million years after the
birth of the Sun, a stellar
event typically put at 4.6
billion years ago. |
|
|
60.
What is the
world's largest
desert? |
|
|
|
The Sahara Desert in
northern Africa is more than
23 times the size of
southern California's Mojave
Desert. |
|
|
 |
|
 |
|
