quake in SIKKIM and ALL-India

[Scala Richter]

Quake in SIKKIM
http://www.dailypioneer.com
Thursday, September 29, 2011
Gangtok - Prime Minister Manmohan Singh Thursday announced a Rs.1,000
crore grant to Sikkim to tide over the devastation caused by the Sep
18 earthquake that killed 80 people and caused large scale damage to
private property.
"The prime minister announced a Rs.1,000 crore package to Sikkim and
also assured all help and cooperation from the central government to
fight the tragedy and devastation caused by the earthquake," a Sikkim
government spokesperson said.
Manmohan Singh made the announcement during a meeting with Chief
Minister Pawan Kumar Chamling at capital Gangtok.
The prime minister earlier made an aerial survey of the worst
affected north Sikkim region in an Indian Air Force helicopter. He
also met some of the injured at the Sikkim Manipal Hospital here.
Manmohan Singh leaves for New Delhi by 4 p.m.
http://www.dailypioneer.com/pioneer-news/top-story/9933-manmohan-anno...
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Jai Maharaj, Jyotishi
Om Shanti
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We will show them within themselves and on the horizons, that it is the truth.

[Scala Richter]

When the earth pushed west
The Sikkim earthquake has thrown both a challenge and an opportunity.
Utpal Kumar, however, is not too sure if we will go for the right
option
The Pioneer
Sunday, September 25, 2011
It was one calamitous September morning that changed Japan forever.
On September 1, 1923, a massive earthquake shook that country's Kanto
Plain, killing at least 100,000 people and reducing the entire region
to rubble. The devastation was so absolute, and the loss so mind-
boggling, that Japan, for a moment, considered shifting its capital
out of Tokyo. Thankfully, better sense prevailed and the people
decided to fight it out -- first by replacing fire-prone, wood and
brick buildings with concrete and steel towers. And, then, by
regularly updating their building guidelines and advancing research
on earthquake safety and disaster management. Ninety years on, Japan
continues to tremble, but it rarely witnesses a trail of death and
destruction on the scale it encountered on that fateful September
morning. Even in March this year, when the country was hit by an 8.9
magnitude earthquake, people suffered not because of tremors but due
to accompanying tsunami that hit the Japanese shores with a
vengeance.
India, too, encountered its 'September moment' last Sunday -- in
Sikkim and its suburbs. In magnitude and scale of destruction, this
might not be a landmark earthquake, but it has done something that is
likely to challenge the authorities to re-assess the country's hazard
zones.
So far, it has been known that India's landmass is inching slowly up,
moving in the north and north-easterly direction. The interaction of
this moving landmass with the Eurasian tectonic plate -- one getting
below the other -- in the Himalayas is what causes most of the
tremors in the region. The September 18 earthquake, however, was not
the result of a forward pushing of the Indian plate; it was caused by
lateral movements.
"The initial analysis of the Sikkim earthquake suggests that it
wasn't caused by one plate thrusting beneath another, but by so-
called 'strike-slip faulting', a mechanism where fault systems slide
side-to-side when two tectonic plates butt heads. Geologists suspect
that the earthquake was due to an intra-plate fault within the upper
Eurasian plate or the underlying Indian plate, rather than the
interface between the two plates," says Prof RB Singh of the
Department of Geography, Delhi School of Economics.
HR Wason, Head of the Department of Earthquake Engineering at IIT
Roorkee, is surprised to see the lateral movement in the region.
"Such movements are not known to happen in the Himalayas," says he.
Prof Paul Segall of Stanford University, however, believes there's
nothing new in all this. "It is not atypical to have diverse types of
fault movement even in an area dominated by convergence of two
plates," he says. Roger G Bilham of Colorado University takes
Segall's argument forward, when he says: "The slip in this earthquake
is an indication of 'differential' northward motion of the Indian
plate and possibly the subsequent adjustment of the Tibetan Plateau
above it."
But, do all these make the region more vulnerable to earthquakes?
"Intra-plate earthquakes do not occur near plate boundaries, but at
the location of ancient failed rifts, because such old structures may
present a weakness in the crust where it can easily slip to
accommodate regional tectonic strain. The earthquake caused by
sideways movement of plates, therefore, is generally located in the
stable interior parts of continents which are believed to be less
vulnerable to hazards," says Singh.
The recent event of intra-plate earthquake in Sikkim has, thus,
pushed the hazard line to further south of the Himalayas. "I believe
the Sikkim quake should serve as a reminder that more parts of the
region than actually thought of are prone to earthquakes and planning
should account for this risk," says Segall.
Currently, as far as earthquakes are concerned, the country has been
divided into five zones. The Northeast, Jammu & Kashmir, and a
significant portion of Himachal Pradesh and Uttarakhand come under
Zone V, which is the most volatile of the earth's seismic centres.
Uttar Pradesh, Delhi and a part of Uttarakhand fall in Zone IV.
Central India is bracketed under Zone III; and, south India comes
under Zone II. Now, after the Sikkim tremor, the entire zone system
has to be reorganised, and the threat perception recast.
Heightened seismic activity
There are seismologists who believe that the earth has experienced a
noticeable increase in seismic activity and intensity over the past
few years. According to latest statistics from the United States
Geological Survey, between 1986 and 1996, there were 15 earthquakes
of magnitude 7.0 or greater. In the next 10 years, the frequency
increased by more than six times. Even the rate of lesser magnitude
earthquakes has increased. Around 120 earthquakes of magnitude 6.0-
6.9 take place every year. And, in the last week alone, we have had
six. At this rate, we would end up having almost three-times more
earthquakes this year!
"I don't think anyone can explain why the activity has increased,"
says Segall. Several theories have been put forth to explain what is
happening. Though most of them are no better than conspiracy
theories, a few seem credible. One of the theories has to do with a
meteor that has returned to the earth's proximity and may be
affecting its gravity balance. Another theory points to solar flares
reaching the earth's surface, thus affecting its electro-magnetic
fields. And, of course, there are some who believe that the earth's
rotational axis has shifted, causing changes in climate, waves and
gravity; this, according to them, has resulted in hurricanes,
earthquakes and tornadoes.
Bilham, though not certain about the reasons behind heightened
seismic activity in recent times, says there is nothing strange in
all this. "It is not unusual for earthquakes to appear more
frequently. They occur rather randomly and hence some periods of time
will seem to contain more than others," he says.
RK Chadha, Chief Scientist, CSIR-National Geophysical Research
Institute, Hyderabad, agrees with Bilham. "The last 100 years of
global data show that during the 1940-50 decade the earth was
seismically more active. Since 2000, we have been again witnessing a
seismically active period, more so after the 9.1 magnitude earthquake
in Sumatra (2004). 'Why', is the million dollar question at the
moment and is the area of active research globally," he says.
Prepare for the worst
At least 38 Indian cities, including Delhi, Mumbai, Kolkata, Chennai
and Ahmedabad, fall within moderate-to-high risk seismic zones. And,
if reports are to be believed, India must prepare itself for
earthquakes of Japan-like frequency and intensity, if not more. "The
northern part of the subcontinent has long been awaiting an
earthquake of magnitude 9," says an Indian Meteorological Department
official on the condition of anonymity. Jean-Philippe Avouac, a
geophysicist at the California Institute of Technology, too, believes
that an earthquake of high magnitude -- like the one witnessed in
Japan -- is overdue. "The Himalayan region has a lot of energy that
needs to be released at some point," he says.
Earthquakes in the Himalayas can go beyond magnitude eight. "There
have been four earthquakes over magnitude eight -- 1897 Shillong,
1905 Kangra, 1934 Bihar-Nepal border and 1950 Arunachal Pradesh. So,
the occurrence of a large magnitude earthquake cannot be ruled out,"
says Chadha.
Such large earthquakes can occur either on thrust faults or strike-
slip. So, the implications of earthquake hazard in the Himalayan
region will not change. But, as the Sikkim quake has revealed, a
large number of cities located in the vicinity of the Himalayas are
no less vulnerable. "Earthquake hazards depend on the local site
conditions in which you are located. It will increase in the
presence of thick pile of sediments where seismic waves are
amplified, causing more damage. This can happen even up to the
distance of 300-400 km. Hence, several cities in the Indo-Gangetic
plains where the thickness of sediments varies between 500 metres and
6,000 metres are exposed to earthquakes. The 2001 Bhuj earthquake in
Gujarat is a perfect example as the tremors led to the collapse of
buildings in Ahmedabad, located more than 300 km from the epicentre;
in 1985, Mexico City suffered heavy damage due to an earthquake whose
epicentre was along the coast in the Pacific Ocean, located more than
300 km away from the Mexican capital," says Prof Chadha.
Quakes not real killers
"In recent earthquakes, buildings have acted as weapons of mass
destruction," remarked a leading seismologist after the devastating
earthquake hit the Caribbean island of Haiti in January 2010, killing
more than 300,000 people. Poor quality construction on the island
made the quake lethal. The 8.8-magnitude earthquake that hit Chile a
month later was 500-times stronger than the Haiti one. And, yet, the
number of casualties in Chile was exponentially smaller, with the
official death toll being confined to a few hundreds.
India is no different from Haiti. The Sikkim earthquake should,
therefore, be a wake-up call for all concerned -- the Government,
policymakers and law enforcers. An earthquake on the scale that Japan
or Chile experienced would lay waste whole cities here. But before
the authorities can do anything, they need to understand that quakes
do not kill people, buildings do. Safety essentially lies in ensuring
quake-resistant construction of buildings. This is where our real
worry lies, as illegal and poor quality constructions continue to be
the bane of urban India, coupled with a lack of awareness of safety
norms.
Bilham believes India is not being pro-active enough in dealing with
earthquake hazards. "Building codes exist and need to be implemented,
not avoided by corrupt or ignorant contractors," the Colorado
University professor says.
"Large earthquakes today will have greater impact because of
haphazard way of urbanisation taking place in the country and also
the density of population in large cities. Mushrooming of multi-
storied buildings, especially in the hilly regions of the Himalayas,
is equally worrisome," says Chadha.
Traditional houses of wood and stone survived the Uttarkashi
earthquake in 1991. One cannot prevent earthquakes from happening,
but one can definitely construct a building that doesn't pose danger
when disasters strike. Perhaps the damage in the Sikkim quake could
have been minimal, had authorities learnt lessons from Uttarkashi and
discouraged the construction of 'modern' buildings in the mountains.
Also, the Government should understand that the seismic process in
Sikkim and its suburbs has been complicated by the presence of
multiple dams on the Teesta river and its tributaries. Though the
role of the dams in the recent tremor is yet to be studied, the
earthquake could have a Teesta angle. After all, in 1970, a major
earthquake in Maharashtra was triggered by the Koyna dam located on
the Sahyadri Hills. The Government needs to tread carefully on the
issue as its "master vision" identifies the Northeast as the
country's "future powerhouse" by building about 168 dams in the
region.
So, last Sunday a choice was given to us: To choose the Japanese way
of tackling earthquakes, or go down the Haitian way. The choice is
ours. The Sikkim quake has only emphasised that the threat is greater
than what we actually believed.
http://www.dailypioneer.com/pioneer-news/top-story/8961-when-the-eart...