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Environment
Uttaranchal
Developing on Shaky Ground
by V.K. Joshi
The entire
Himalayan belt from northwest to northeast is prone to earthquakes.
Actually the Himalayas are there because of a big shaking event that
rocked our sub-continent some 20 million years ago. The Himalayas were
borne as a consequence of collision of two continents, the moving Indian
sub-continent and the stable Asian continent. One can visualize the
immediate post collision earthquakes that must have shaken our land from
the fact that even today the rubbing of two continental plates shakes us
from our slumber.
The Himalayan
State of Uttaranchal came in to existence in November 2000. The infant
state is developing fast to attain adulthood. As per the census of 2001
the population of Uttaranchal is 84.80 lakhs. Over the past decade the
population has attained a growth rate of 1.9%. The State has 13
districts spread over an area of 53,119 Sq. km. Carved out of Uttar
Pradesh the State has taken away 66% forests of the mother state. Along
with the natural bounties, the new State has also received its share of
natural disasters. Flash floods, landslides, rock fall, debris slide and
the most dreaded one, the Earthquake are some of the natural hazards of
Uttaranchal.
We shall turn
few pages of recent history and try to examine how safe is the state for
large investments from the point of view of earthquakes.
 Geological
Survey of India (GSI) has carried out extensive surveys in the region
and the information compiled from the data gathered over two centuries
is very interesting. Thomas Oldham, the founder of GSI mentions in 1869
of an earthquake in that killed 300 people in upper reaches of Ganga at
Barabal on 1st September 1803 at 0135 hrs. The earthquake is said to
have damaged even the Badrinath shrine. Thereafter, the annals of the
GSI are full of information on the earthquakes in Uttaranchal. On 25th
May 1816 there was a major earthquake at Gangotri that caused several
landslides.
 Again
on 28th August 1916, and on 29th July 1980, Dharchula in Pithoragarh
district was rocked, causing severe destruction of houses. The latter
did not spare even the well-constructed buildings. Incidentally,
Dharchula has been rocked again only a few days ago and a damage survey
is being carried out.
It was 20th October 1991 we were camping at Dehradun. I was busy talking
with my daughter till late in the night and slept nearly at mid-night.
Sleep was in its initial stages when the ground started to shake. It
felt as if we were sleeping on a bed of waves. It was an earthquake, we
ran out to safety. Next day we learnt that the earthquake occurred at
Uttarkashi in Garhwal. It cut short the life span of 768 people, injured
5066 people and damaged nearly one hundred thousand houses located
within an area of 24,000 sq km. A total of 45,765 houses were completely
destroyed. The earthquake was 6.6 on Richter's scale.
 Geological
Survey Of India investigated the earthquake immediately. It was found
that in the higher reaches of Bhagirathi River a 20 sq km area faced the
worst wrath of the nature. Prabhas Pande an ace seismologist of GSI
spoke to a survivor of a devastated village in Uttarkashi. The sobbing
villager recounted, 'In the very early hours of the day we were awakened
by some unknown force. The ground first heaved and then shook most
violently causing collapse of our poorly constructed dwellings of
mud-masonry walls and slate roof.' The story was same all over in the
epicenter tract.
Damage was not restricted to only houses. Innumerable landslides were
also generated in an area of about 2500 sq km of the Himalayan terrain.
These disrupted the road communication. Telephone and electric wires
were too snapped, poles uprooted along with countless trees. Post
disaster mitigation process largely depends on communication facilities.
A 53 meter long bridge over the Bhagirathi River too was dislodged and
thrown in to the river. Thus even pedestrians could not travel to their
destinations for some days
 The
scars of fear of devastation of 1991 earthquake at Uttarkashi had just
started to heal, when Chamoli area in Garhwal was rocked in the wee
hours of 29 March, 1999. The magnitude of the earthquake can be
understood from the fact that at that time many people in Lucknow were
watching a late night popular Hindi movie when they felt the ground
quivering. Geological Survey Of India immediately rushed a team of 33
experts to identify the affected areas and map the magnitude and
intensity of the quake.
An earthquake, though a terrifying experience for the common man, offers
opportunity to the geologists to unravel the mysteries of the earth's
interior. Such studies help in planning for a safer future.
The survey indicated that areas covered by isoseist of IV and V were
20,900 and more than 108,000 sq km. The tremors were felt in a vast area
including places like Delhi, Lucknow , Varanasi, Kanpur, Jaipur,
Faridabad, Gurgaon, Ambala, Chandigarh, Ludhiana , Jammu, Srinagar ,
Shimla etc. As per the reports 106 people died. Maximum deaths, 63 were
from reported from Chamoli. In Chamoli, Rudraprayag, Tehri and Pauri
districts of Garhwal and Bageshwar district of Kumaon, 187619 houses
were damaged. Fortunately infrastructure services like water,
electricity and telephones were not much affected, though several
landslides blocked the road.
During the past 200 years Uttaranchal has experienced 116 earthquakes.
Out of these 28 were of intensity those caused havoc. The studies
carried out by GSI reveal that the seismic activity is concentrated
along a 50km wide belt in Bhagirathi, Mandakini and Kali river valleys.
The earthquakes have cost loss of 1000 precious lives and property worth
crores of Rupees.
Uttaranchal has been placed in the zone V and IV as per the
Seismotectonic Atlas of India published by the GSI in the year 2000.
Prabhas Pande, Director, Earthquake Geology, GSI in one of his recent
papers has grouped Uttaranchal and adjoining areas of Nepal into four
classes of hazard. Very High Hazard area includes parts of west Nepal
and in this area the possibility of an earthquake M>6 exist every ten
years. Next is the High Hazard Zone. This covers almost 36% of
Uttaranchal. Major parts of Uttarkashi, Chamoli, Bageshwar, Almora,
Pithoragarh and Champawat fall in this zone. Earthquakes of M>6<7 can be
expected in this region every 100 years. Yet another 41% of area of
Uttaranchal, including Purola, Tehri, Rudraprayag, Gairsain and Haridwar
fall in the Moderate Hazard Zone. It is conjectured that an earthquake
of M>5<6 can occur in these areas every 100 years. The remaining 23% of
the State including Roorkee, Pauri, Nainital and Udham Singh Nagar fall
in the Low Hazard Zone. The zoning is based on the available earthquake
data and is open to refinement when further data is available.
How grave is the threat of high magnitude earthquake in future can be
understood from the fact that Max Wyss of World Agency of Planetary
Monitoring and Earthquake Reduction has also estimated that an
earthquake of magnitude 8.1 can claim 96,000 to 199,000 lives and 210 to
433 thousand injured in Dehradun alone. Similar views have been aired by
Prof A.S. Arya of IIT Roorkee that an earthquake of high magnitude can
claim up to 100,000 to 150,000 lives.
It is clear that the State is prone to earthquakes. Safety measures need
to be followed keeping in mind the possibilities of a disaster.
Uttaranchal has the potential of 18,000 MW of Hydroelectric power
generation. Presently only 10% of the potential is being tapped. Power
generation is a major source of revenue for the State. While
constructing further power generation schemes, the factor of earthquake
has to be the foremost consideration.
About 22% of the population of the State lives in the six most
earthquake prone districts. The Government has disaster management
schemes. Unfortunately most of these schemes have arrangement for post
disaster scenario. Relief after the disaster is no doubt invaluable, but
a strict control over present construction activity is a must to ensure
that the future generations live unscratched in earthquake safe houses.
Multistoried, poorly designed and unfavorably located structures in
vulnerable areas like Dharchula and Uttarkashi speak volumes about the
apathy or ignorance of the authorities. The Central Building Research
Institute at Roorkee has designs of safe houses to suit all types of
pockets for the people of Uttaranchal.
Pre-disaster mitigation and preparedness for the disaster is vital for
the safety and security of the population in disaster prone areas. The
local population and the Government both should realize that a poorly
designed housing complex spells doom for the residents of tomorrow. It
should be noted that an earthquake itself cannot kill people, they die
of roof collapse. Therefore, precautions taken now will go a long way in
development of Uttaranchal.
September 10, 2006
Images
Uttarkashi earthquake: Damaged government building
Uttarkashi earthquake: A bridge destroyed
Uttarkashi earthquake: A building destroyed
Chamoli earthquake: A building destroyed
(All images curtsey GSI)
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