26.
Tens of thousands are feared dead after the Bhuj earthquake in the Indian state
of Gujarat. Horrifyingly, seismologists believe that worse is yet to come.
Roger Bilham, a geologist at the University of Colorado at Boulder, believes
that more than 60% of the Himalayan region to the north of the country is
overdue for an earthquake of magnitude 8 or more on the Richter scale. An
earthquake of this severity would threaten densely populated areas in the
Ganges valley, including the Indian capital, New Delhi.
Earthquakes happen when the rocky tectonic plates which make up the earth’s
crust shift suddenly. These plates are in constant, albeit very slow, motion.
As a result, huge pressures build up in them over the years, and this
accumulated strain is often released as an earthquake. The Bhuj earthquake was
unusual, because the strain had built up in the middle of a plate (most
earthquakes occur along plate boundaries.) In the northern part of the
sub-continent, where the Indian and Eurasian tectonic plates meet, the greatest
pressure is exerted, over tens of millions of years forming the Himalayas. It
is here that the most powerful Indian earthquakes tend to occur, and where
Bilham thinks the next big one in India will happen, although the entire
sub-continent is riddled with faults on the verge of disaster, having been
under pressure for so long.
How much that worries the Indian authorities—or at least how much they are
willing to act on their worries—is a different question. Bilham and Vinod Gaur
of the Center for Mathematical Modeling and Computer Simulation in Bangalore
claim that until recently Indian seismological research has neglected a
technique known as geodesy, which measures the strains accumulating in, and
distorting the surfaces of, tectonic plates. The patterns of those distortions
cannot be used to predict quakes, but they can be used to work out which areas
are most at risk from them.
In the past decade, geodesy has been revolutionized by global positioning
system (GPS) technology, a satellite-based method of locating points on the
earth’s surface precisely GPS-based geodesy has now begun in several parts of
India, but, according to Bilham and Gaur, its application is being hampered by
military secrecy requirements. The zones of maximum quake risk are near India’s
borders, and the government does not want to make a present of accurate maps to
its enemies.
Such concerns, while understandable, can be taken too far, according to Bilham
and Gaur. Gujarat is a case in point. Fastidious documentation of the area is
already available from a survey carried out in the late 19th century; nothing
that seismology adds could possibly help an enemy. Besides, more civilian
deaths have occurred in the area from earthquakes than in recent wars. Bilham
says that the Indian government has even forbidden him to use a gravity meter
in the region. Such a meter measures whether a point is moving away from the
center of the earth, and therefore indicates a build-up of strain that might be
released as an earthquake.
Adapted from an article in The Economist
Questions 1—10
Do the following statements reflect the claims of the writer in the reading
passage? In boxes 1—10 on your answer sheet, write:
T if the statement reflects the writer c claim
F if the statement contradicts the writer
NG if there is no information about this in the passage
1. The next earthquake in India will occur in the Ganges valley.
2. Earthquakes are caused by sudden movements in the earth’s crust.
3. The Bhuj earthquake was a typical occurrence.
4. The population of Bhuj was wiped out by the earthquake.
5. The Himalayas were formed by the collision of two major tectonic plates.
6. Geodesy is the science of predicting earthquakes.
7. The Indian military makes use of GPS technology.
8. India’s borders are vulnerable to earthquakes.
9. Gujarat has not been properly mapped.
10. The Indian government is cooperating fully with Bilham and Gaur’s work.
Answer: 1-F,2-T,3-F,4-NG,5-T,6-F,7-NG,8-T,9-F,10-F
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