Chinese earthquake could be due to Himalayan glacier-melting
The May-12 Richter-7.9 earthquake in the
Sichuan province of China may be caused by glacier-melting caused in turn by
global warming. The result is so common it even has a name �glacial
earthquake�. The Sichuan earthquake could be one of these glacial
earthquakes, and if so certainly not the first one, nor the last.
Relevant to Sichuan are the Himalayas.
Himalayan glaciers have shrunk due to three factors:
� Higher temperature
thaws the glaciers. According to the International Center for Integrated
Mountain Development (ICIMOD), �The average temperature in the Himalayas in
the northern part of Nepal rose about 2 degrees between 1970 and 1994; in
the rest of Nepal, more than 3 degrees.�
� Global warming changes snow into
rain that melts the glaciers, and form glacial lakes � The amount of
snowfall has decreased.
The Nepalese Himalayas alone contain more
than 3,000 glaciers, each kilometers long and hundreds of meters wide,
weighing billions of tons. There are approximately 70 extra-large glaciers
in Himalaya, covering about 166 km2 or 17% of the mountain area.
With glacier meltdown comes weight
redistribution on a mammoth scale.
The melting of these glaciers has been
accelerating.
� Thickness-wise, in the period of 2000-2004, a thinning of
about 10 m occurred below 4000 m altitude, and 2 m above 5000 m.
�
Length-wise, the Chhukhung Glacier, for example, retreated at about 5 m per
year in the late 1970s, which increased to about 20 m per year in and after
the 1990s.
� Weight-wise, the shrinking of the AX010 Glacier, which
accelerated from 2.7 m per year in the 1980s to 12.5 m in and after the
1990s, resulted in the loss of more than 1 million tons of ice in 20 years
through 1999.
The Himalayas and the surrounding mountain
ranges are not the most geologically stable region to begin with. The
northward incursion of the Indian subcontinent into SE Asia continues and
the Himalayas continue being built and elevated, as does the folding of the
surrounding ranges, including those in the Sichuan province of China where
the earthquake occurred. The redistribution of weight by the glacier melting
will cause seismic events in areas where ill-settled sub-plates hang on to
each other by their fingernails as it were, slipping violently against each
other at the slightest disturbance.
If the above is true, then we can expect
more devastating earthquakes to come. Likewise, it can be predicted that the
massive melting of the Greenland and Antarctic land-ice will generate
earthquakes in and around these regions.
Anthony Marr, founder and president
Heal Our Planet Earth (HOPE)
Compassion for Animals Road Expeditions (CARE)
Global Emergency Operation (GEO)
www.HOPE-CARE.org
www.MySpace.com/AnthonyMarr
www.ARConference.org
The following article
gives more details.
Glaciers� melting main reason for
quakes: seismologists
By Khalid Mustafa
1/14/2007
ISLAMABAD: Seismologists all the over the
world have found that another serious consequence of glaciers melting is
�glacial earthquakes� - the new indicator after analysing worldwide 182
earthquakes between January 1993 and October 2005.
Explaining the relation between glaciers
melting and earthquakes, a WWF consultant told The News that when a glacial
ice of one cubic metre melts, it means lightening of one tonne load on
earth�s crust (called tectonic plates).
The WWF consultant says �melting of one
cubic metre glacial ice frees the plates to move against each other and
causes friction needed to make earthquakes. But as the glaciers melt and
their load on the plate lessens, there is a greater likelihood of an
earthquake happening to relieve the large strain underneath.�
Even though shrinking glaciers make it
easier for earthquakes to occur, the forcing together of tectonic plates is
the main reason behind major earthquakes.
The Indian plate moves 5cm closer to Asia
each year and Tibet moves 32mm closer to Asia each year but glacier melting
accelerates or triggers earthquakes.
In a new study, NASA and United States
Geological Survey (USGS) scientists found out that in the 1979 earthquake in
southern Alaska, which was called the St. Elias earthquake, was promoted by
wasting glaciers in the area. The earthquake had a magnitude of 7.2 on the
Richter scale.
In Pakistan, the snow-capped mountain
glacier is shifting very rapidly toward higher region, particularly in Azad
Jammu Kashmir and Kaghan/Naran Valley. Some glaciers are vanishing due to
massive human intervention and deforestation.
During the last 20 years, the shifting of
snow-capped glacier can easily be checked from Sarwaali Peak (6,326 meters)
- the highest mountain in Azad Kashmir. This shifting ice-cap and the
vanishing of a small glacier along the Line of Control up to NJ 9842 may be
another cause of the 2005 earthquake.
Unfortunately, all major Himalayan
glaciers, including Siachen, are on the Eurasian continent (tectonic plate).
The Indian plate that is already moving toward it by 1.6 inches per year due
to the melting of glaciers is another great threat to the population living
in the region.
Arshad H Abbasi predicted that the
Himalayan glacier�s melting may cause more severe earthquakes in South Asia.
Melting of glaciers has serious
consequences because when a glacier melts it unleashes pent-up pressures on
the earth�s crust, causing extreme geological events such as earthquakes and
tsunamis.
A cubic metre of ice weighs nearly a tonne
and most of the Himalayan glaciers are hundreds of metres thick. When the
weight is removed through melting, the suppressed strains and stresses of
the underlying rock come to life. The weight suppresses the earthquakes, but
when ice melts earthquakes are triggered.
The retreat of ice sheets 10,000 years ago
also triggered a wave of powerful earthquakes in the Himalayas.
Since iso-static rebound continues for
thousands of years, it may still be contributing to quakes in eastern
Canada, says geoscientist Patrick Wu of the University of Calgary.
Interestingly, the earthquake data of
Siachen glacier and the Saltoro range itself speaks of its retreat. Between
the years 1983 and 2000, earthquakes having magnitudes 4 to 5.2 were
recorded. These earthquakes activated avalanches and had consequences as
regards casualties of both the forces fighting over the Siachen glacier. As
reported only 3 per cent of the casualties were caused by hostile firing.
The remaining 97 per cent have fallen prey to the altitude, weather and
avalanches.
A joint Indian-Chinese team plans to chart
remote Himalayan glaciers that are rapidly melting, threatening the great
rivers that give life to the subcontinent - one of South Asia�s most fertile
regions. But it could not give any substantial result unless the melting of
the third pole (Siachen) is not addressed.
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