A century after eruption, Krakatau still dangerous
A century after eruption, Krakatau still dangerous
By MMI Ahyani
BANDUNG (JP): Captain FCP Vereker had just dropped anchor off
of Banquey Island in Kalimantan on Aug. 27, 1883 when he suddenly
heard a series of distant explosions. Having alerted his crew,
Vereker noted in the frigate's logbook that the explosions
resembled shots but he could not determine where they originated.
In Saigon, Manila, Bangkok and Perth, similar bangs were heard
on the same day. In Singapore, the long-distance telephone
connections between the port and the Ishore islands were dead for
a few hours. The Singapore port authority even sent two ships to
investigate the source of the continuing blasts, to no avail.
Meanwhile, British Navy Commander Coghlan in Perth, Australia
mobilized his sailors, believing the shots had come from the sea.
Captain Vereker in Kalimantan, Commander Coghlan in Perth, and
the administrations of many other cities didn't know that the
explosions emanated from a small volcano in the middle of the
Sunda Strait called Krakatau. Vereker was 1,235 miles away,
Saigon 1,164 miles away, Manila 1,800 miles, Bangkok 11,413 miles
and Perth 1,900 miles away from the enraged volcano.
Accounts of the Monday, Aug. 27, explosion came from many
regions of the world. People wondered why the sky suddenly turned
green and why the temperature dropped 0.5 degrees centigrade.
About 36,000 people didn't have the luxury of wonderment, they
had been drowned by a devastating tsunami (tidal wave). Krakatau
had ejected 18 cubic kilometers of volcanic material, triggering
a tsunami 30 meters high that wiped out 298 small towns along the
coasts of Banten and South Lampung. The rolling wave was caused
by the disappearance of two volcanoes, Danau and Perbuwatan, and
part of Rakata Island.
Krakatau's outburst was one of the most violent eruptions
known to man and brought about global environmental changes in
the 19th century, including a 0.5 degree centigrade drop in
temperature until 1888.
The Krakatau cluster consists of four islands, Rakata,
Sertung, Panjang and Small Krakatau. Its geographical position is
6 03'00" - 6 10'24" south latitude and 105 21'20" - 105 27'44"
east longitude. The presence of Mount Krakatau in the middle of
the Sunda Strait is believed to be closely related to the
tectonic condition of this region. Considering the unique
location of the Krakatau group from a geological-volcanic
perspective, professor M.T. Zen at the Bandung Institute of
Technology presumes the group is located in a volcanic-tectonic
depression in Sumatra.
The Sunda Strait is now very important to the development of
western Indonesia because it connects Java and Sumatra. Around
this region there are many strategic and hi-tech industries,
installations, beautiful tourism areas and millions of people.
Since the famous blast 112 years ago, Krakatau is believed to
have entered a new cycle of activities. Although very active,
with three or four eruptions a year, no more truly dangerous
blasts have occurred. It is dangerous enough, however, to warrant
around-the-clock scrutiny.
Krakatau is monitored by the Directorate of Volcanology at an
observation post at Pasauran Carita. Another post is now being
built at Kalianda in South Lampung.