TEXT 1
A geyser is the result of underground
water under the combined conditions of high temperatures and increased pressure
beneath the surface of the earth. Since temperature rises approximately 1 F for
every sixty feet under the earth's surface, and pressure increases with depth,
the water that seeps down in crack and fissures until it reaches very hot rock
in the earth interior becomes heated to temperature in excess of 290 F. Because
of the greater pressure, the water shoots out of the surface in the form of
steam and hot water. The result is a geyser. In order to function, then a
geyser must have a source of heat, reservoir where water can be stored until
the temperature rises to an unstable point, an opening through which the hot
water and steam can escape, and underground channels for resupplying water
after an eruption.
Favorable conditions for geyser exist in some regions of the world including
New Zealand, Iceland, and the Yellowstone National Park area of the United
States. The most famous geyser in the world is Old Faithfull in Yellow Park.
Old Faithfull erupts almost every hour, rising to a height of 125 to 170 feet
and expelling more than ten thousand gallons during each eruption.
TEXT 2
Approximately 74,000 years ago on
the island of Sumatra, Indonesia , a volcanic eruption so violent occurred that
it proved to be apocalyptic for the human race. Scientist estimate that the
eruption may have ejected up to 6,000 km3 of magma pulverized rock and
sufficient sulfur gases to form 5,000 megaton of stratospheric sulfuric acid
aerosols. The suspension of so much material in the earth’s atmosphere resulted
in a volcanic winter that lasted all year long, every year for several years
.The severe drop in global temperature had catastrophic effect on vegetation
and the food chain dependent upon it for survival-including humans.
Scientists have examined the genetic code of seemingly disparate and distance
race of people and found there’s actually very little genetic variability in
the entire human race. The evidence indicates that something happened to the
human gene pool approximately 74,000 years ago where only very few humans
remained alive on the planet (say 5,000 to 10,000), and the current population
has grown from these selectively few genotypes. Our existence in such great
number today (over 6 billion strong) is a testament to our tenacious ability to
survive.
TEXT 3
The term of “tsunami” comes from the
Japanese which means harbor ("tsu") and wave ("nami"). A
tsunami is a series of waves generated when water in a lake or a sea is rapidly
displaced on a massive scale.
A tsunami can be
generated when the sea floor abruptly deforms and vertically displaces the
overlying water. Such large vertical movements of the earth's crust can occur
at plate boundaries.
Sub-duct ion of
earthquakes is particularly effective in generating tsunami and occurs where
denser oceanic plates slip under continental plates. As the displaced water
mass moves under the influence of gravity to regain its equilibrium, it
radiates across the ocean like ripples on a pond.
Tsunami always brings
great damage. Most of the damage is caused by the huge mass of water behind the
initial wave front, as the height of the sea keeps rising fast and floods
powerfully into the coastal area
Get over the idea that only children should spend their time in
study. Be a student so long as you still have something to learn, and
this will mean all your life.
(“Aturlah ide layaknya anak kecil
yang habiskan waktu mereka saat belajar. Jadilah penuntut ilmu selama kau masih
memiliki sesuatu untuk dipelajari, dan hal ini akan menjadi tujuan seluruh
hidupmu”)
Henry L. Doherty
