Home' Position : Position Aug Spt 2015 Contents How a small team of Australian
predicted the second major
earthquake in Nepal.
On 25 April 2015, a 7.8 magnitude
earthquake devastated Nepal,
claiming over 8,800 lives, injuring
over 9,000 and drastically affecting
millions of others. A week after the initial
quake, a research team at the University
of New South Wales (UNSW) School of
Surveying and Geospatial Engineering
received and analysed the first valid
post-quake satellite image and came to a
contentious conclusion: that another major
earthquake was soon on its way for Nepal.
The finding was derived from a
method called differential interferometric
synthetic aperture radar (DInSAR), in
which satellite imagery revealed a far
lower than expected amount of ground
displacement. Using imagery provided
by the Japanese ALOS-2 satellite before
and after the initial quake, the analysis
revealed a displacement of 1.5 metres.
Considering the expected damage of an
earthquake of such magnitude, as well
as the geomorphology of the area, it was
calculated that it should have been closer
to a much higher 3.2 metres.
Sure enough, ten days later on 12
May a second 7.3 magnitude earthquake
struck the region, killing over 200 more
people, injuring thousands of others, and
disrupting the vital progress made in the
ongoing recovery and delivery of aid.
Thankfully, the research team
at Sydney's UNSW had realised the
importance of their research, and sought
to have their findings spread to the
authorities involved before the second
quake had struck.
"There is no doubt that people in the
quake-affected regions had been warned
of more strong aftershocks based on our
findings and, as a result, had become
more vigilant before the strong after-
shock," said Linlin Ge, lead researcher
and Associate Professor at UNSW, who
strongly believes the aftershock was the
one his team had predicted.
"I believe it is due to the lower than
expected displacement as measured by
DInSAR. In fact, we went further and
publicised our findings based on an image
collected on 2 May 2015 in order to mini-
mise casualties due to strong aftershocks."
The findings reached the Nepal
Geological Society (NGS), Nepal's home
ministry, and the China Earthquake
Administration, and also received
attention in the mainstream media
such as the Australian Broadcasting
Corporation and China Science Daily.
In the past, Prof Ge and his team also
successfully applied DInSAR analysis
for the 2008 Sichuan earthquake, the
2010 Canterbury earthquake and the
2011 Christchurch earthquake. They also
successfully mapped the 2009 Victorian
bushfire and 2011 Queensland flood in
near real-time with satellite imagery.
"It should be a standard procedure"
Despite the attention their prediction
did receive, apart from organisations
such as the US Geological Survey
(USGS), the Geospatial Information
Authority of Japan (GSI) and specialised
research centres such as that at UNSW,
DInSAR is too new a technology
to be considered by all relevant
authorities in a timely manner. Most
local administrations and educational
institutions aren't familiar with the
technology and rely on the work of
academic researchers such as the UNSW
team. Below is an extract from an email
received by Linlin Ge from an astronomy
academic living in Nepal after the second
earthquake (the academic's name has
been removed for privacy reasons):
Date: 27 May 2015
Subject: I am from Kathmandku
I have gone thorough [your article]
After this I could not find the image
from the Japanese satellite. The earthquake
of April25 and May 12th did sufficient
displacement inside it or not? We all are
afraid of such quake Please notify me
we may have another big greater than 6
earthquake soon or not? What does your
research says? Are you focusing Nepal?
Please if you can give us some result of
your study. Thank you for your kind support
and research work.
streets of Chautara,
Copyright: IOM 2015
(CC BY 2.0).
18 position August/September 2015
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