The Child Grows Eruption
plumesVolcanoes typically build up in fits and starts. After 1883,
Krakatau was dormant until 1927, when a new cone began to build at the
edge of the 1883 caldera. In 1928 alone, 22,358 earth tremors were
registered
by a temporary volcanological observatory on the island of Panjang,
while eruption plumes were seen to reach 1,200 meters high. However, the
first three attempts to break the surface formed only temporary
ash-cone islands, which were destroyed by marine erosion and submarine
sliding on the steep slope of the submerged caldera. The second of these
islands was visited by a party of scientists in May 1929, shortly
before it slipped back into the sea. They collected several insects,
including a large black cricket and a brown ant. The present island, the
fourth, emerged in August 1930, and over the next few years, it
alternated between periods of quiet and rapid growth. At times,
particularly in the early 1930s, the eruptions produced huge quantities
of fine ash, which, aided by the alternating monsoon winds, have been
deposited on the developing forests of Panjang and Sertung islands, a
few kilometers distant (in opposite directions), causing extensive
damage. By September 1932, the island was 47 meters high and had a
typical low wide crater some 700 meters in diameter. By 1933, the height
had increased to 67 meters, and by 1941, it had doubled again to reach
132 meters.
The
1940s was a period of relatively little activity, but in 1952 and 1953,
the volcano sprang back into action, producing large quantities of
ejecta. This was produced in such quantities and to such heights (clouds
reaching 4,000 meters at times) that once again it was carried across
to Panjang and Sertung islands, damaging as much of 90 percent of their
forests to a degree visible from boats passing through the group. On
Anak Krakatau itself, the colonization of plants and animals was
abruptly halted by these eruptions, as the vegetation was more or less
eliminated. A new, high inner cone formed, that was about 500 meters in
diameter, enclosing a new crater lake. The records then indicate a
further period of inactivity, until 1958, with further ash eruptions
occurring over the period to 1963, during which some traces of ash
reached sites on the coast of Java, some 40 kilometers distant.
This young and active volcano has been growing
around 6 feet a year and still continues doing so. It grew by the accumulation
of ash, and suffered a devastating eruption in 1952, and other very destructive
one in 1971. It is now 300 m high and 5 Km in diameter, and is still active
spurting fire and cinder, this like moonlike landscape. It is lonely volcanic
island in the middle of the sea. The northeast coast, north foreland and east
foreland are now vegetated; the succession of vegetation is still at an early
stage, Casuarinas equisetifolia (cemara) being the dominant tree.strait area
were devastating, killing more than 36.000 people. That total volume of
material ejected by the eruption is estimated at some 18 - 21 cubic kilometers,
30 km high into the atmosphere with an ash cloud circling the earth several
times. Causing " blue suns" range moons" in Europe and
North America .
The amount of the sun's energy reaching the
earth was reduced, and in the year or two that followed, annual average
temperatures in the northern hemisphere were than usual. Generally rough except
Anak Krakatau as its volcanic activities sustain the overall height. In 1976 it
was only 169.67 M. in 1973 it was 189.48 and the last measurement was in 1985
when its height was 240 m, and was in 2008 more than 300 m.
TopographyGenerally
rough except Anak Krakatau as its volcanic activities sustain the
overall height. In 1976 it was only 169.67 M. in 1973 it was 189.48 and
the last measurement was in 1985 when its height was 240 m, and was in
2008 more than 300 m.
Vegetation
The
primary vegetation includes the Kilangir (Chsiocheton Microcarpus),
Ketapang (Terminal Catppa),Melinjo (Gnetum Gnemon),Mara (Macaranggo
Fanarius),Cemara (Casuarina Equisetifolia),Waru (Hibiscus Filioeus)
Kampis (Hemadia Peltata), Hampelas (Ficus Ampelas), Cangkudu (Morinda
Citrifolia).
Wild Life
Not
many animal to see, how ever if we are lucky enough, you might see the
Bottle Nosed Dolphin (Delphmus Delphie), Flying fox (Pteropus Vampirus),
Monitor Lizard (Varanus Salvator), Green Turtle (Cholonia Mydas),
Champeleon (Calotes Cristaleus), or Python (Python Sp), Birds include
the stork Billed " Kingfisher (Tonyseptra Galatea), Common Tern (Stama
Hirundo) and white " Bellied sea Eagle (Heliastur Leucogaster).
Anak KrakatauThe Volcano Today: Will It Blow Again? By
the mid-1990s the island had overtopped both Panjang and Sertung
islands, reaching a height of about 300 meters, with a diameter varying
between 3 and 4 kilometers. It has some way to go before it reaches the
height of the last fragment of the 1883 volcano Rakata, at some 780
meters. What are the chances of the cycle of growth and violent
destruction repeating itself? Volcanologists have a number of means of
assessing the likelihood of catastrophic eruptive activity. One
important measure is the silica content of the ejecta. As the magma
increases in silica content its viscosity increases, making it more
difficult for contained gases to escape. When they do, there is a
cataclysmic eruption, and silica content then falls to begin the cycle
again. The Krakatau data broadly fit this Magmamodel, and do not suggest
that another caldera collapse event is imminent. But you can never be
certain with volcanoes. In any event, it is not a volcano to take
lightly. Over the last 70 years, it has deposited something like a meter
of volcanic ashes on Panjang and Sertung islands, and has repeatedly
cut-back the development of its own ecosystems. When in full eruption,
it is an awesome sight, with huge volcanic bombs thrown hundreds of
meters from the eruption center, and great plumes of ash ascending many
hundreds and sometimes thousands of metres. Recent outpourings of lava
have also been spectacular, for instance, in November 1992, a four day
period of activity saw 35,650 square meters covered by lava of about 5
meters in thickness -- an estimated volume of over 2 million cubic
meters
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