Krakatau volcano is located in the Sunda Strait between the islands of Java and Sumatra. In 1883, it erupted catastrophically, killing over 36,000 people due primarily to massive tsunamis. The eruption destroyed most of the pre-1883 volcanic edifice and reshaped the island. Krakatau appears to cycle through different eruptive phases over time, from basaltic to andesitic to dacitic, with each cycle culminating in a massive dacitic eruption.
2. Krakatau volcano is best known for its
catastrophic 1883 eruption which resulted in
at least 36000 deaths, primarily due to the
resulting massive tsunamis inundating the
surrounding coastlines. The eruption
reshaped Krakatau, destroying most of the
pre-1883 edifice.
3. Krakatau is located in the shallow waters of the
Sunda Strait over a brittle zone in the
lithosphere, where a NNE trending volcanic
fault zone meets a fracture zone running in a
NNW-SSE direction along which all historical
volcanism at Krakatau has taken place.
4. The Sunda Strait is seismically and tectonically
active and marks a transition zone between
the Sumatra and Java fault zones which are
both associated with
subduction of the
Indo-Australian Plate
under the South East
Asian Plate upon
which Krakatau is
located.
5. Krakatau is an unusual
stratovolcano which appears to
cycle through basaltic, basic
andesitic, acidic andesitic and
dacitic phases. Each of these
cycles is thought to culminate in
a massive destructive dacitic
eruption before the cycle
recommences at the basaltic
stage.
6. Before the 1883 eruption , lots of seismic
energy could be felt, with some earthquakes
felt as far as Australia. Eventually eruptions of
ash started and explosions occurred regularly ,
but then activity died down at the end of May
. On the 16th of June , activity came back with
more explosions and ashes covered the skies
for 5 days and earthquake shocks could be felt
again.
7. By August 26th conditions were severe, with heavy ash
fall and small tsunamis. On the 27th there was an
explosion that could be felt and heard 3,000 miles
away. The explosion was followed by a tsunami told
to be at least 30 meters high.
This explosion was roughly 4
times as strong as the Tsar
Bomba the most powerful
thermonuclear weapon
detonated by man, and the
explosion was equivalent to
200 megatons of TNT.
