Headlines
Thirty-eight Indian cities in high risk earthquakes zones
New Delhi, April 27
At least 38 Indian cities
lie in high-risk seismic zones and nearly 60 percent of the
subcontinental landmass is vulnerable to earthquakes. Barring rare
exceptions, such as the Delhi Metro, India’s hastily-built cities are
open to great damage from earthquakes.
The earthquake that
devastated Nepal on saturday and jolted northern India, damaging
buildings as far apart as Agra and Siliguri, was expected by geologists,
who have warned of more Himalayan earthquakes caused by the growing
pressures of the sub-continent grinding into the Asian mainland.
Very
few buildings in India meet the standards prescribed in "Indian
Standards Criteria for Earthquake Resistant Design" - first published by
the Bureau of Indian Standards in 1962, the latest revision being in
2005. These are not enforced, so almost no one knows such
earthquake-resistant standards and guidelines for home-owners exist.
The
Delhi Metro is one of the few Indian structures built to withstand a
quake. Many of the houses built in Bhuj after the Gujarat quake of 2001
are now earthquake-resistant. The rare building and high-rise may be
designed for quakes.
But nothing has changed since 1993, when a
relatively milder earthquake of magnitude 6.4 in Maharashtra’s Latur
district killed nearly 10,000 people in what was considered a
non-seismic zone. Most died because shoddily constructed houses
collapsed at the first major shake, as they did in Gujarat eight years
later.
The government of India today lists 38 cities in moderate
to high-risk seismic zones. “Typically, the majority of the
constructions in these cities are not earthquake-resistant,†notes a
2006 report written by the United Nations for the ministry of home
affairs. “Therefore in the event of an earthquake, one of these cities
would become a major disaster.â€
The earth’s landmasses ride like
gigantic rafts on "plates", or sections of the earth’s outermost layer,
the crust. These plates frequently slip and slide, causing earthquakes.
We don’t feel the small ones. The big ones, literally, shake us up.
The
Himalayas and north India are on particularly shaky ground. Sometime in
the geological past, before humans, India broke off from an ancient
supercontinent called Gondwana, a name still used for what is now
Chhattisgarh.
The Indian plate skewed north, displaced an
ancient sea, travelled more than 2,000 km - the fastest a plate has ever
moved - and slammed into the Eurasian plate, creating the Himalayas.
India
still grinds northeast into Asia at roughly 5 cm every year. The last
significant - but not geologically significant - quake in this area was
the 2005 temblor in Pakistan-administered Kashmir, which sits directly
atop the clashing Indian and Eurasian plates. Around 80,000 people died.
About 60 percent of India is vulnerable to earthquakes caused
by the great, northward grind of the Indian subcontinental landmass.
The
only serious earthquake that modern India remembers is the temblor that
killed about 20,000 in Gujarat in 2001. The 2004 tsunami, which
resulted from the third-most most severe quake ever recorded, 9.3 on the
Richter scale, occurred when the Indian plate slid with greater
violence than it normally does under the neighbouring Burma plate, upon
which rest the Andaman and Nicobar Islands.
It caused a
100-km-long rupture in the crust, thrusting the seafloor upwards and
pushing up masses of water, setting off tsunamis that killed 230,000
people in 14 countries.
No Indian metropolis has witnessed a
serious earthquake, although Delhi lies in high-risk Seismic Zone 4.
Srinagar and Guwahati are in the highest-risk Zone 5, and Mumbai,
Chennai and Kolkata lie in Zone 3. History serves a warning that a big
one may come at any time. Those lessons come from Bihar in 1934 and
Assam in 1950.
Although its epicentre was 10 km south of Mount
Everest, the Bihar earthquake of 1934 was felt from Mumbai to Lhasa,
flattening almost all major buildings in many Bihar districts and
damaging many in Calcutta, now Kolkata. At 8.4 on the Richter scale, it
was pretty severe, killing more than 8,100 (Mahatma Gandhi said it was
punishment for the sin of untouchability).
The 1950 Assam
earthquake may have geologically set the stage for a really big one in
the Himalayas, according to geologists. Now that 65 years have passed,
it may be time for a big one.
(In arrangement with Indiaspend.org, a data-driven, non-profit, public-interest journalism platform)