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TENNANT AND DISTRICT TIMES THURSDAY 25 JANUARY 2018 5
THIS week marks 30
years since the largest
earthquake ever recorded
in Australia struck Ten-
Three big quakes, the largest
with a magnitude of 6.6, rattled
the town on 22 January 1988,
triggering tens of thousands of
aftershocks. The latest of these
was a 3.1 magnitude quake
recorded two weeks ago on 11
The quake (the epicentre was
south-west of town) created
a 20 kilometre fault line and
caused the recently completed
Amadeus pipeline to concertina
because of the pressure.
The earthquake was previ-
ously thought to be Australia’s
third largest - after two earth-
quakes in Western Australia
in 1941 and 1968 - however
a reclassification in 2016 by
Geoscience Australia has now
placed the Tennant Creek quake
at the top of this list.
In 2012, Tennant Creek was
listed as the country’s biggest
earthquake hotspot on the haz-
ard map, the premise of which
is that earthquakes over the
next 100 years are most likely
to occur in the same areas as in
the past 100 years.
Although there had been
foreshocks in 1986 and 1987,
locals assumed the rumbles
were caused by blasting out at
The earthquakes took most
people by surprise on that Fri-
Buildings swayed and rattled
as years of red dust collected in
ceilings poured out and items
were shaken off shelves. The
mess was most obvious at the
Foodbarn where supermarket
items were tipped into the aisles
as alarmed shoppers scattered
Armed with a camera to cap-
ture images for the Tennant &
District Times, Athena Afianos
went out to the site the morn-
ing after the earthquakes with
police officers Mark McAdie
and Max Pope.
“There were lots of cracks
and fissures of varying sizes
all over the ground as well as
raised areas where the ground
had been pushed up,” she said.
Athena recalled a team of
workers including earthmov-
ers, welders, engineers and NT
Gas officials who had been sent
out to check the pipeline which
ran through the epicentre of the
“They were digging down to
check the line and as the soil
was exposed they could see the
pipe concertina because of the
stress it was under,” she said.
“It was quite amazing.
“They worked for about three
days in sweltering heat and
humidity to get the gas run-
“I know that once works were
completed, they all had a well-
deserved celebration at Brian’s
“It had been a huge and stress-
Pipe welder Laurie Atkins,
who led the team which re-
paired the gas pipeline, told The
Australian Pipeliner magazine
that at first no one could under-
stand how it happened.
“It was all new to everybody
and very new to me. It was the
first time it had happened in
Australia, I think, so no one
had a lot of experience with it
or knew what to expect.”
Laurie said his team progres-
sively exposed the pipeline
towards the fault line in order
to relieve the stress in the pipe
but as this happened, the pipe
snaked all over the place.
Because it was in a concertina
shape, once it was exposed by
backhoes, and still had some
stress in it, nobody actually
knew which way the pipe was
going to swing or move when
we cut it,” he said.
“We had to drill a hole in it
and light it up and then cut it
live with oxy-acetylene equip-
ment and, as the flames were
coming out, I got in the bucket
of a backhoe to be lowered into
the hole to cut the pipe.
“Cutting the bottom of the
pipe was the hardest because
we had no idea which was it
was going to go. If it had swung
up it might have hit me. If it
went left and I was standing
there, it would squash me.”
The pipe swung as the team
predicted and about 100 metres
of the stressed pipe was with
pre-hydro tested, thicker wall
emergency pipe which has
managed to withstand all other
earthquake activity to date.
The section of the damaged
pipe that was removed is now
part of the Questacon science
exhibition in Canberra.
The damage bill from the
earthquake was estimated to be
$2.5 million even though only
superficial structural damage
The following article by J.R. Bowman, The 1988
Tennant Creek NT Earthquakes: A Synthesis, appeared
in the Australian Journal of Earth Sciences, 1992.
Three large intraplate earthquakes near
Tennant Creek, Northern Territory, on 22
Following a year long series of
foreshocks, extensive surface faulting
accompanied an extraordinary sequence
of earthquakes in the Precambrian shield
of central Australia on 22 January 1988.
The main shock sequence included
earthquakes of magnitude Ms 6.3, 6.4,
and 6.7 .
Hundreds of aftershocks were recorded
in the epicentral area in the first few days
after the main shocks, and the sequence
continued into 1991; the largest
aftershock occurred nearly 9 hours after
the third large main shock.
The three largest earthquakes were
felt over more than one-quarter of the
land surface of Australia, and in high-
rise buildings up to 2000 km from the
epicentre. A buried natural-gas pipeline
was shortened by 1m at the surface
rupture, and buildings in the town of
Tennant Creek, 30 km to the north-
northeast, sustained minor damage.
Focal mechanism solutions indicate
thrusting for the first and third large
earthquakes, and a combination of
thrust and strike-slip motion for the
second. Ground deformation and offsets
along roads, fences, and the pipeline
also indicate mainly thrust-faulting. The
mean azimuth of the P-axes for the first
three focal mechanisms is N31Â°E, in
close agreement with the maximum
principal stress direction determined
from in-situ stress measurements made
in a nearby gold mine.
l The 1988 earthquakes created a 20 kilometre-
long fault line. Photo: ATHENA AFIANOS
l Workers repair the damage to the gas
pipeline which ran through the epicentre of the
earthquakes. Photo: ATHENA AFIANOS
l A section of the damaged pipeline is now
part of the Questacon Science exhibition.
l A much-younger Mike Nash pictured at the
fault line south-west of Tennant Creek in 1988.
Photo: CHARLIE HANNA.
l Police officer Mark McAdie tests the depth of
the fault line. Photo: ATHENA AFIANOS.
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