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News from ICTP 96 - Features - SAND
Under the umbrella of the SAND group, Indian and Italian scientists have joined efforts to examine one of the world's most destructive forces: earthquakes.
Seismic Changes...
One Step at a Time
In the early morning hours of
26 November 1997, two moderate earthquakes, the first 5.7 in magnitude
and the second 6.1, rattled the Italian hill provinces of Umbria
and Marche, located in central Italy about 150 kilometers northeast
of Rome. The event marked the first of a series of earthquakes
that would continue to rumble across the region for the next six
weeks--not only disrupting one of Italy's most picturesque areas
but also fraying the nerves of the more than 100,000 people who
live there. Ten deaths and US$10 million in damages would mark
the earthquake's toll. Yet the world's most enduring image of
this tragedy would be the collapsed roof of the Basilica of Saint
Francis of Assisi, which left a heap of rubble on the church floor
containing jagged puzzle pieces of one of the Western world's
great artistic treasures: 13th century frescoes by the famed artist
Giotto.
On 26 January 2001, a much stronger earthquake, 7.6 in magnitude,
struck the Indian state of Gujarat in the northeast corner of
the world's second most populous nation. The earthquake, which
took place on the Indian national holiday of Republic Day, was
felt throughout northwestern India, western Nepal and much of
Pakistan. As the Indian government sought to cope with the catastrophe,
it was soon evident that this earthquake would be the worst natural
disaster in India since the nation had achieved independence in
1949. More than 20,000 people died, 165,000 were injured, and
hundreds of thousands more left homeless. Experts estimate the
recovery and reconstruction efforts will cost more than US$5 billion.
"We tend to think of earthquakes as unusual events--and thank
goodness they are not everyday occurrences," says Giuliano
Panza, head of the Structure and Non-Linear Dynamics of the Earth
(SAND) group, which is an ICTP hosted activity. "But earthquakes
are much more common than most people realise. For example, between
the 1997 earthquake in Umbria/Marche and the 2001 earthquake in
Gujarat, we experienced 16 major seismological events worldwide,
including earthquakes in Afghanistan, Turkey, Colombia and Taiwan."
And since the earthquake in India less than six months ago, in
February a major earthquake in El Salvador killed at least 1100
people and left more than 1 million people homeless in that poor
Central American country, and in March a moderate earthquake in
Japan caused millions of dollars in damages. As Panza notes, "it's
part of the human condition to be crushed and buried by earthquakes."
As Panza also points out, earthquakes may be "global phenomena
but their severity and impact are often determined by local and
regional conditions." For this reason, he says, "modelling
may be an effective strategy for assessing both the prospects
for a seismological event and the potential dangers likely to
be experienced if an earthquake of a certain magnitude were to
strike."
For the past decade, Panza, with the help of Abdelkrim Aoudia
and other colleagues associated with the SAND group and the University
of Trieste's Department of Earth Sciences, has developed and refined
scenario-based models that have enabled scientists to better understand
the anticipated behaviour of the Earth in such seismically active
regions as central Italy and northwest India. "In effect,"
Panza notes, "the models help us envision what may happen
without waiting for an earthquake to occur."
"Over time, we have acquired a great deal of knowledge about
the Earth's geology," adds Aoudia, "that can be put
to good use together with theoretical insights concerning the
Earth's dynamical behaviour." Marrying observed data to theoretical
constructs, and then testing the conclusions against the Earth's
complex movements during a seismological event, has helped the
SAND group to draw increasingly more reliable pictures of what
may occur during future earthquakes. The goal of the seismological
modelling process is not much different than what climatologists
and meteorologists are doing with increasing confidence in projecting
future changes in climate and weather.
Panza and his colleagues recently brought their modelling expertise
to India as part of the first-ever Indo-Italian Workshop on Seismic
Risk Evaluations, held in Hyderabad, 6-9 March 2001. He was accompanied
by Aoudia and a number of other scientists from ICTP and the University
of Trieste and other Italian research institutions. Those traveling
to India with Panza included Roberto Sabadin, University of Milan;
Fabrizio Mollaioli, University of Rome; Peter Suhadolc and Fabio
Romanelli, University of Trieste; Giacomo Di Pasquale, National
Seismic Survey; and Leonello Serva, Italian National Environmental
Protection Agency.
The Italian contingent was joined by a group of some 30 Indian
scientists, including seismologists, geologists and geotechnical
engineers. Among those in attendance were Vinod Gaur, scientist
emeritus, Centre for Mathematical Modelling and Computer Simulation
(CMMACS), Bangalore, who is one of the true pioneers in seismology
research in his home country, and Harsh Gupta, former director
of the National Geophysical Research Institute (NGRI) and presently
secretary to the government of India in the Department of Ocean
Development.
"Modelling methodologies served as the organising principle
of the workshop," explains Aoudia, "but on a more general
level we discussed such topics as the development of seismological
observational networks and geo-databases, the underlying principles
and goals of hazard assessments, and the current state of research
on seismic microzonation and seismic vulnerability."
Indo-Italian Workshop on Seismic Risk Evaluations
"The Indo-Italian workshop had been conceived and planned
under the protocol of cooperation between the two countries,"
says Satish Bhatia, deputy director and head, Earthquake Hazard
Assessment Group at NGRI. "The schedule, in fact, was finalised
in early January 2001. However, the earthquake later that month
in Gujarat made the workshop an even more timely event."
Bhatia also says that "overall India has a reasonably good
number of well-trained and experienced seismologists but their
numbers need to be expanded and their training strengthened to
address the full range of seismological and emergency management
issues that our nation face."
"After a brief initial period of shock and disbelief,"
he notes, "the rescue and recovery efforts in the area struck
by the earthquake in Gujarat proved to be the most effective in
the history of such emergencies in our country. While the scope
of devastation and despair cannot be understated, the government,
with the help of local grassroots organisations and other national
as well as some international agencies, made an extraordinary
effort in dealing with such a devastating situation."
The nation's risk management and mitigation efforts will receive
another boost later this year when an Earthquake Risk Evaluation
Centre (EREC), which has been in the planning stages for some
time, becomes operational.
"The institution," Bhatia says, "is designed to
be a centre of excellence in all phases of seismological research.
For example, researchers will conduct state-of-the-art studies
of earthquake-prone areas and develop seismic hazard and vulnerability
maps based on the most up-to-date information and techniques."
The Indo-Italian workshop not only gave participants an opportunity
to learn more about each other's work but also provided a platform
for developing future joint activities. Three topics selected
to receive special attention from the emerging Indo-Italian seismological
network are:
(1) Microzonation of selected cities in India, coordinated
by the Geological Survey of India and the University of Trieste's
Department of Earth Sciences.
(2) Site-specific seismic hazard assessment in megacities
using the most advanced modelling techniques, coordinated by the
National Geophysical Research Institute (NGRI), Hyderabad, and
the University of Trieste's Department of Earth Sciences.
(3) Estimation of vulnerability and seismic risk assessment
for megacities of high hazard, coordinated by the Building
Materials Technology Promotion Centre (BMTPC), Delhi, and the
University of Rome La Sapienza.
Each of these activities, which will involve an exchange of visits
among scientists in Italy and India, will include the direct participation
of the SAND group. The effort is expected to get off the ground
sometime next year and a report on the progress that has been
made as a result of these cooperative research ventures will be
presented at the International Geological Congress in Florence,
Italy, in 2004.
As Panza observes: "We no longer have to wait for an earthquake
to take place and then measure the ground motion to assess its
impact. We can now use geological and geophysical data to model
seismograms based on theoretical insights and assessments."
That's the goal both Indian and Italian scientists hope to advance
in the years ahead as they work together to better understand
the awesome physical forces responsible for violent shifts in
the Earth's crust.
For additional information about the Indo-Italian network
and, more generally, the SAND group, please contact panza@ictp.trieste.it
or browse the group's homepage at www.ictp.it/sand.