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Posted By - Hampton Inn Santa Clarita
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Earth performed the ultimate magic trick last week, making an island
appear out of nowhere. The new island is a remarkable side effect of a
deadly Sept. 24 earthquake in Pakistan that killed more than 500 people.
Satellite images snapped a few days after the earthquake-triggered island
emerged offshore, near the town of Gwadar, reveal that the strange
structure is round and relatively flat, with cracks and fissures like a
child's dried-up mud pie.
The French Pleiades satellite mapped the
muddy hill's dimensions, which measure 576.4 feet (175.7 meters) long
by 524.9 feet (160 m) wide. Aerial photos from Pakistan's National
Institute of Oceanography suggest the gray-colored mound is about 60 to
70 feet (18 to 21 meters) high.
Gwadar
is about 230 miles (380 kilometers) from the earthquake's epicenter.
The magnitude-7.7 earthquake was probably centered on the Chaman Fault,
Shuhab Khan, a geoscientist at the University of Houston told
LiveScience last week.
Geologists think the new island, named
Zalzala Koh, is made of erupted mud, spewed from the seafloor when
either trapped gases escaped or subsurface water was violently expelled.
The new island could be the result of a mud volcano. Mud volcanoes
form when hot water underground mixes with sediments and gases such as
methane and carbon dioxide. If the noxious slurry finds a release valve,
such as a crack opened by earthquake shaking, a mud volcano
erupts, according to James Hein, a senior scientist with the U.S.
Geological Survey in Santa Cruz, Calif. Geologists from the Pakistan
Navy report that Zalzala Koh is releasing flammable gas. But seafloor
sediments commonly hold methane-producing bacteria, so the possible
methane coming from the island isn't a clincher to its identity.
Shaking
from the powerful Sept. 24 earthquake could have also loosened the
seafloor sediments offshore of Pakistan, jiggling them like jelly. The
great rivers coming down from the Himalayas dump tons of water-saturated
sediment into the Arabian Sea every year. The new island could be a
gigantic example of a liquefaction blow, when seismic shaking makes
saturated sediments act like liquid, and trapped water suddenly escapes,
Michael Manga, a geophysicist at the University of California,
Berkeley, told LiveScience.
Similar islands have appeared offshore of Pakistan after strong earthquakes
in the region in 2001 and 1945. If the earlier examples hold, the soft
mud island won't last a year, disappearing under the erosive power of
the pounding of waves from monsoon storms.
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