The
Great Earthquake and Tsunami of 26 December 2004 in Southeast
Asia and the Indian Ocean
George
Pararas-Carayannis
Copyright © 2005.
All Rights Reserved
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The
Great Earthquake of 26 December 2004 in Southeast Asia
![](tsu2004Indonesia.jpg)
![](tsu2004IndoBathChart.jpg)
On Sunday, 26 December
2004, the greatest earthquake in 40 years occurred about 150
kilometers off the west coast of northern Sumatra Island in Indonesia.
The earthquake generated a disastrous tsunami that caused destruction
in 11 countries bordering the Indian Ocean.
Origin Time
and Epicenter
The great tsunamigenic
earthquake occurred on Sunday, 26 December 2004, at 00:58:50
UTC (6:58:50 a.m. local time). The epicenter was at 3.298 N,
95.779 E and its focal depth was very shallow (much less than
33 km - possibly about 10km)
Magnitude
and Energy Release
The quake was widely
felt in Sumatra, the Nicobar and Andaman Islands, Malaysia, Myanmar,
Singapore, Thailand, Bangladesh and India.
According to the U.S.
Geological Survey (USGS NEIC (WDCS-D)), the moment magnitude
of the earthquake - which is larger than the Richter magnitude
- was 9. Such magnitude would make this earthquake to be the
fourth largest in the world since 1900 - and the largest since
the 1964 Alaska earthquake.
However, on the basis
of subsequent analysis of additional seismograms from around
the world, scientists at Northwestern University determined the
earthquake's magnitude to be 9.3 and not 9.0, as originally estimated.
Therefore, the calculated energy release was 1.13 X 10 (raised
to the 30 power) dynes-cm , or three times larger than originally
thought. The revised estimate makes this earthquake to be the
second largest ever instrumentally recorded. The largest earthquake
ever recorded, which measured 9.5, was in Chile on May 22, 1960.
Tectonic Setting
The region where the
great earthquake occurred on 26 December 2004, marks the seismic
boundary formed by the movement of the Indo-Australian plate
as it collides with the Burma subplate, which is part of the
Eurasian plate. However, the Indo-Australian tectonic plate may
not be as coherent as previously believed. According to recent
studies reported in the Earth and Planetary Science Letters (vol
133), it apears that the two plates have separated many million
years ago and that the Australian plate is rotating in a counterclockwise
direction, putting stress in the southern segment of the India
plate.
For millions of years
the India tectonic plate has drifted and moved in a north/northeast
direction, colliding with the Eurasian tectonic plate and forming
the Himalayan mountains. As a result of such migration and collision
with both the Eurasian and the Australian tectonic plates, the
Indian plate's eastern boundary is a diffuse zone of seismicity
and deformation, characterized by extensive faulting and numerous
large earthquakes.
USGS graphic showing
the migration of the Indian tectonic plate![](tsu2004IndoIndiaPlate.gif)
The epicenter of the
26 December 2004 earthquake was near the triple point junction
of three tectonic plates where major earthquakes and tsunamis
have occurred in the past.
Previous major earthquakes
have occurred further north, in the Andaman Sea and further South
along the Sumatra, Java and Sunda sections of one of the earth's
greatest fault zones, a subduction zone known as the Sunda Trench.
This great trench extends for about 3,400 miles (5,500 kms) from
Myanmar (Burma) south past Sumatra and Java and east toward Australia
and the Lesser Sunda Islands, ending up near Timor. Slippage
and plate subduction make this region highly seismic. The volcanoes
of Krakatau, Tambora and Toba, well known for their violent eruptions,
are byproducts of such tectonic interactions.
In addition to the
Sunda Trench, the Sumatra fault is responsible for seismic activity
on the Island of Sumatra. This is a strike-slip type of fault
which extends along the entire length of the island.
The Burma plate encompasses
the northwest portion of the island of Sumatra as well as the
Andaman and the Nicobar Islands, which separate the Andaman Sea
from the Indian Ocean. Further to the east, a divergent boundary
separates the Burma plate from the Sunda plate.
More specifically,
in the region off the west coast of northern Sumatra, the India
plate is moving in a northeastward direction at about 5 to 5.5
cm per year relative to the Burma plate.
Three-dimensional
computer-generated graphic of the seabed in the vicinity of the
recent earthquake in Southeast Asia. (Picture / Reuters, Royal Navy vessel
HMS Scott(9 Feb 2005))
Seismicity
of the Region
Earthquakes originate
at two principal tectonic sources in Indonesia. The major tectonic
feature in the region is the Sunda Arc that extends approximately
5,600 km between the Andaman Islands in the northwest and the
Banda Arc in the east. The Sunda Arc consists of three primary
segments; the Sumatra segment, the Sunda Strait Segment and the
Java Segment. These locations represent the area of greatest
seismic exposure, with maximum earthquake magnitudes of up to
7.75 or even more on the Richter scale (as this latest earthquake
with Moment Magnitude 9 indicates - and which occcurred on the
Sumatra segment).
The region where the
earthquake occurred - and particularly the Andaman Sea - is a
very active seismic area. According to the literature (Bapat
1982) from 1900 to 1980, a total of 348 earthquakes were recorded
in the area bounded by 7.0 N to 22.0 N and 88.0 E to 100 E. However,
only five of these earthquakes in the Bay of Bengal had magnitudes
equal to or greater than 7.1 ( ranging from 7.1 to 8.5). Also
Sumatra is in the center of one of the world's most seismically
active regions. Earthquakes with magnitude greater than 8 struck
Sumatra in 1797, 1833, and 1861. Earthquakes with magnitude greater
than 7 struck offshore islands in 1881, 1935, 2000, and 2002.
British
Geological Survey graphic of the seismicity of Southern Asia
(note high concentration of earthquakes in the Andaman Sea and
Northern Sumatra)
Aftershocks
As of 1 January, 2005,
there were about 84 aftershocks with magnitudes ranging from
5.0 to 7.0 in the region of Northern Sumatra and the Nicobar
and Andaman Islands. Twenty six (26) of these - including the
largest- occurred on 26 December 2004, the same day as the main
earthquake. Since 1 January 2005, many more aftershocks have
occurred. The aftershocks are expected to continue for several
weeks and months. Some of the major aftershocks have occurred
in the vicinity of the epicenter of a past earthquake which had
occurred on 26 June 1941 and some in the area near the Nicobar
Islands where the 1881 earthquake had occurred.
The distribution of afteshocls suggests that the earthquake resulted
by the sudden slip of these two plates and that there was a slip
as well as an upward thrust of the Burma plate along this boundary.
Chronological
Sequence of Major Aftershocks Along the West Coast of Northern
Sumatra and in the Nicobar and Andaman Island Region Following
the Major Earthquake om 26 December 2004
MAGNITUDE |
DATE |
UTC-TIME |
LATITUDE |
LONGITUDE |
DEPTH |
REGION |
|
|
|
|
|
|
|
8.9 |
2004/12/26 |
00:58:51 |
3.298 |
95.779 |
10.0 |
West
Coast of Northern Sumatra |
5.9 |
2004/12/26 |
01:48:47 |
5.393 |
94.423 |
10.0 |
West
Coast of Northern Sumatra |
5.8 |
2004/12/26 |
02:15:58 |
12.375 |
92.509 |
10.0 |
Andaman
Islands |
6.0 |
2004/12/26 |
02:22:02 |
8.83 |
92.532 |
10.0 |
Nicobar
Islands |
5.8 |
2004/12/26 |
02:34:50 |
4.104 |
94.184 |
10.0 |
West
Coast of Northern Sumatra |
5.8 |
2004/12/26 |
02:36:06 |
12.139 |
93.011 |
10.0 |
Andaman
Islands |
6.0 |
2004/12/26 |
02:51:59 |
12.511 |
92.592 |
10.0 |
Andaman
Islands |
5.9 |
2004/12/26 |
02:59:12 |
3.177 |
94.259 |
10.0 |
West
Coast of Northern Sumatra |
6.1 |
2004/12/26 |
03:08:42 |
13.808 |
92.974 |
10.0 |
Andaman
Islands |
7.3 |
2004/12/26 |
04:21:26 |
6.901 |
92.952 |
10.0 |
Nicobar
Islands |
5.7 |
2004/12/26 |
06:21:58 |
10.623 |
92.323 |
10.0 |
Andaman
Islands |
5.7 |
2004/12/26 |
07:07:10 |
10.336 |
93.756 |
10.0 |
Andaman
Islands |
5.8 |
2004/12/26 |
07:38:25 |
13.119 |
93.051 |
10.0 |
Andaman
Islands |
6.5 |
2004/12/26 |
09:20:01 |
8.867 |
92.382 |
10.0 |
Nicobar
Islands |
6.2 |
2004/12/26 |
10:19:30 |
13.455 |
92.791 |
10.0 |
Andaman
Islands |
6.3 |
2004/12/26 |
11:05:01 |
13.542 |
92.877 |
10.0 |
Andaman
Islands |
Crustal
Displacements and Rupture
The distribution of
the larger aftershocks indicates that the two tectonic plates
(the India plate and the Burma subplate) slipped for about 1,200
km along their boundary. The aftershocks extend from northern
Sumatra (approximately 3 degrees North Latitude) to the Andaman
Islands (approximately 14 degrees north). Therefore, the length
of the overall rupture is estimated to be about 1,200 km.
However, the slippage
does not appear to be continuous. It appears that it occurred
in two phases along two sections of the great fault that parallels
the Sunda Trench. The rupture started near the epicenter off
the western coast of North Sumatra and progressed - at a fast
rate - northward to the Andaman islands along a preexisting major
fault. For the first 500-600 km the orientation of the rupture
(the quake's strike) was appoximately 320- 330 degrees. Subsequently
the rupture continued - at a much slower rate in an approximate
North-South direction - for another 500 -600 km along another
segment of the northern Sunda fault system. This is probably
the same segment that ruptured during the 1941 Andaman Islands
earthquake - which also generated a destructive tsunami.
It has been estimated
that this megathrust faulting along the India and Burma boundary
has resulted in a shift that averaged about 15 meters with maximum
slip being 20 meters. The vertical upward movement of the sea
floor may have been several meters - possibly as much as 5 meters
or more in some places. At some of the islands there may be subsidence
while at others there was upthrusting. Field surveys of the islands
off Summatra and of the Nicobar and Andaman islands - when completed
- will provide better estimates of net crustal movements.
The
Great Tsunami of 26 December 2004 in the Indian Ocean
The
great earthquake of December 26, 2004 was extremely damaging
and resulted in many deaths. However, most of the destruction
and deaths were caused by the catastrophic tsunami waves it generated.
Massive tsunami waves wiped out entire coastal areas across southeastern
Asia, Sri Lanka, India, Thailand, Myanmar and islands in the
Andaman Sea and the Maldives in the Indian Ocean.
DEATH TOLL
The tsunami waves
caused considerable destruction and killed people more than 2,000
kilometers away, in the Seychelles and in Somalia . As of February
10, 2005, the global death toll has been raised to 226,566 and
continues to rise. The demographics in this part of the world
are not very good. There are many remote islands in the Nicobar,
Andaman, Maldives and off the African coasts, so there are many
unreported deaths.
No Tsunami Warning Issued
The large tsunami
which struck 11 of the nations that border the Indian Ocean was
a complete surprise for the people living there, but not for
the scientists who are aware of the tectonic interactions in
the region. Many seismic networks recorded the massive earthquake,
but there was no tide gauges or other wave sensors to provide
confirmation as to whether a tsunami had been generated. There
was no established communications network or organizational infastructure
to pass a warning of any kind to the people coastlines.
No Tsunami Warning
System exists for the Indian Ocean as there is for the Pacific.
The Pacific Tsunami Warning Center in Honolulu had no way of
providing warning information to the region. Part of the problem
is that most of the countries in the region have underestimated
their potential tsunami threat from the Northern end of the Sunda
Trench. Review of historical records would have revealed that
a very destructive tsunami occurred in 1941, in the same general
area. This particular tsunami killed more than 5,000 people on
the eastern coast of India, but it was mistaken for a "storm
surge". Thousands more must have gotten killed elsewhere
in the islands of the Bay of Bengal in 1941, but there has been
no sufficient documentation. Unfortunately, no Regional Tsunami
Warning System, Preparedness Program, or effective Communications
Plan exist for this part of the world.
Tsunami Generating Area
Based on the plate
tectonics of the convergence zone that has formed the SundaTrench
and on aftershock distribution, the tsunami generating area is
believed to be a somewhat irregular, broken up ellipsoid which
changes from a Northwest Southeast orientation of about 330 degrees
in the lower section to an almost North - South 360 degrees orientation
in the upper section.
The major axis of
the ellipsoid is estimated to be approximately 1,200 km and its
minor axis to be about 180 km. It is believed that this ellipsoid
type of block movement occurred along an oblique but very shallow
subduction angle and that the Burma subplate was thrusted upward
by several meters (as much as 5m in some places) with an oblique
lateral movement of as much as 15 meters and possibly as much
as 20 meters along the southern tsunami generating region. These
are rough estimates which may have to be revised when more data
becomes available. Also, the earthquake's relatively slow slippage
along the 1,200 kms long rupture added additional energy to tsunami
generation.
A preliminary estimate
of the Tsunami Generating Area ( Modified USGS map showing the
earthquake epicenter, the distribution of initial major afteshocks
,and the interaction of major tectonic plates along the Sunda
Trench )
A personal communication
was received from Indonesia that at Simeulue, an island close
to the epicenter off the coast of Northern Sumatra, there was
only vertical displacement but no tsunami. Surprisingly, residents
of beach communities claimed that no tsunami waves were observed,
no deaths from the tsunami were reported, but that the island
rose and is now several kilometers longer. No information has
been provided on how much the island rose, but preliminary data
indicates that it may have been as much as 5 meters.
The reason that the
tsunami did not cause deaths and destruction on Simeulu Island
is because the amount of crustal uplift was greater than the
height of the waves. Additional eyewitness accounts or observations
will help clarify whether this was the case.
A preliminary estimate
is that the tsunami generating area involved about 280-300,000
square kilometers of the ocean floor. This estimate will probably
be revised and corrected as well, as more data on aftershock
distribution becomes available and when tsunami travel times
to operating tide gauge stations in the Bay of Bengal are obtained
- if any exist or survived the tsunami impact.
Also, field surveys
and data collection will help determine the net crustal displacements
on the islands off Sumatra and in the Nicobar and Andaman Islands.
This will permit more accurate determination of the volume of
undersea crustal displacements that contributed to such catastrophic
tsunami generation.
These results have
implications for why Sri Lanka suffered such a great impact and
also indicate that the chances of similar large tsumanis occurring
in the same area are reduced.
Evaluation of tsunami reccurrence in the region
Indonesia is surrounded
by four major tectonic plates, the Pacific, the Eurasian, the
Australian and the Philippine plates. All these major tectonic
plates and their subplates are presently active. Major earthquakes
and tsunamis can be expected in the semi-enclosed seas and along
the Indian Ocean side of Indonesia. Major earthquakes in the
semi-enclosed seas can generate destructive local tsunamis in
the Sulu, Banda and Java Seas. Major earthquakes along the Sunda
Trench can generate tsunamis that can be destructive not only
in Indonesia but to other countries bordering the Indian Ocean.
In the immediate vicinity
off Northern Sumatra, most of the stress and energy that had
accumulated were released by the crustal movement that caused
the 26 December 2004 earthquake. The subduction of the India
tectonic plate underneath the Burma plate caused upward thrusting
of an extensive block and generated the destructive tsunami.
There was significant slip and rupture for about 600 km and possibly
a less significant slip for another 400 km along the Nicobar
and Andaman Islands. Thus, it is unlikely that another major
earthquake will occur in the immediate region off Northern Sumatra
in the near future, but stress will start building up again.
Also, it is quite possible that not all of the energy was released
in the Nicobar and Andaman section of the Sunda Trench by the
26 December 2004 earthquake - in which case the next major earthquake
could occur there sooner than one off Northern Sumatra.
Although the danger
of another major tsunami has passed, strong aftershocks in the
region could possibly generate small local tsunamis. Aftershocks
can be expected to last for many weeks and months in the region,
but they should diminish in strength with the passage of time.
Most of the aftershocks will result from gravitational adjustments
of the crustal material that was moved during the major earthquake.
The aftershocks represent nature's way of restoring stability
and temporary equlibrium. It is unlikely that a destructive tsunami
will occur again soon in the same region, however caution is
advised for the coastal residents in Northern Sumatra and in
the Nicobar and Andaman islands. If an afteshcok is stong enough
and it is strongly felt, evacuation to higher elevation is advised.
In fact, strong shaking of the ground is nature's warning that
a tsunami may be imminent.
Furthermore - and
though the stress in the region off Northern Sumatra has been
released by the 26 December 2004 earthquake - this does not necessarily
mean that another earthquake further north or further south cannot
occur. In the North, a repeat of the 1881 Nicobar Islands or
of the 1941 Andaman Islands earthquakes and tsunamis can be expected
in the future - although it is difficult to say how soon. Such
events seem to occur on the average of every 50 years.
To the South, the
movement of the tectonic plates may have added stress along other
tectonic boundaries. A repeat of earthquakes and tsunamis along
the Sunda Trench off the central region of Western Sumatra, as
in 1833 (magnitude 8.7) and 1861, is very possible. Such earthquakes
and tsunamis can be expected every hundred years or so. In fact,
the 26 December 2004 earthquake occurred along the section that
did not rupture during the 1861 earthquake. It took approximately
144 years to occur. However, this does not mean that it will
take that long for the next destructive tsunami to occur again
off central or northern Sumatra. Destructive tsunamis are possible
in the next 20 years or less. A repeart of the 1833 earthquake
could generate a devastating tsunami. This section of the Sunda
megathrust is one of the more likely sources of a destructive
tsunamis in the region.
Other seismic regions
further south have the potential of generating destructive tsunamis
even sooner. As in 1977, a major tsunami could be generated in
the eastern section of the Sunda Trench that would affect not
only Indonesia, but the northern and northwestern coasts of Australia.
Map of Sumatra
showing Simeulue Island to the west near the epicenter of the
26 December 2004 earthquake where uplift and elongation of the
island were observed and reported. Note proximity to Lake Toba,
the submerged caldera of the volcano which, about 75,000 years
ago, was the site of the greatest volcanic explosion on earth
in the last two million years. The explosion of Toba sent 2,800
cubic kilometers of material into the earth's atmosphere and
caused major climatic changes
Effects
of the 26 December 2004 Tsunami in the Bay of Bengal and in the
Indian Ocean
Waves of up to 10.5 meters in
height struck Northern Sumatra, the Nicobar and Andaman Islands,
Thailand, Sri Lanka, India. Destructive waves also struck the
Maldives, Somalia, Kenya and the islands off the African coast.
The tsunami was recorded by tide gauge stations not only in the
Indian Ocean, but in the Pacific as well. In Manzanillo, Mexico,
the tide gauge recorded a wave of 2.6 meters.
Eighteen (18) countries
bordering the Indian Ocean were affected by the tsunami. These
were: Indonesia, Thailand, India, Sri-Lanka, Malaysia, Myanmar,
Bangladesh, Maldives, Reunion Island (French), Seychelles, Madagascar,
Mauritius, Somalia, Tanzania, Kenya, Oman, South Africa and Australia.
DEATH TOLL -The tsunami had its greatest
impact and casualties in Indonesia, Thailand, India, Shri-Lanka,
Malaysia, Myanmar, Maldives and Somalia. Eleven (11) countries
reported deaths, some in tens of thousands.The death toll thus
ar has been reported as 226,566. However, this is an underestimate
as thousands are still missing and many more may have been killed
in remote islands. More than 1.5 million people were left homeless
around the region.
The following is a
brief summary compiled from numerous government, U.N., and media
sources.
Efforts are being
made to obtain tsunami wave heights. This section of the report
will be changed and updated as more information becomes available.
INDONESIA
Tsunami waves of up
to ten meters swamped the smaller outlying islands of Sumatra
as well as its northern and western coastal areas - about 100
km (60 mi) from the earthquake epicenter . Hardesh hit was the
northern Aceh province. Nearly all the casualties and damage
took place within this province. Very heavy damage occurred as
far South as Tapatkuan. The waves also propagated around the
northern tip of Sumatra into the Straits of Malacca and struck
coastal settlements along the northeast coast as far east as
Lhokseumawe.
According to the latest
official reports (Ministry of Health) 166,320 people were killed,
127,774 are still missing and 655,000 people were displaced in
Northern Sumatra. A total of 110 bridges were destroyed, 5 seaports
and 2 airports sustained considerable damage, and 82% of all
roads were severy damaged. The death toll is expected to rise.
The following is a summary of the tsunami impact in Northern
Sumatra.
Banda Aceh - The tsunami waves completely destroyed the
city of Banda Aceh's infrastructure and killed thousands of its
inhabitants. Banda Aceh is capital of the Aceh province. in Northern
Sumatra.
Leupung - The tsunami completely obliterated
Leupung, a town in the district (Kabupaten/Kota) of Aceh Besar,
close to the city of Banda Aceh. Most of the town's 10,000 inhabitants
perished. It is estimated that only two to seven hundred people
survived.
Gleebruk - The waves completely
destroyed Gleebruk, a village in the district (Kabupaten/Kota)
of Aceh Besar just to the southwest of Banda Aceh.
Teunom - The tsunami hit hard Teunom,
a town of 18,000 people in the Aceh Barat (West Aceh) district
of the Province of Aceh. According to official estimates about
8,000 people lost their lives.
Calang - The waves completely devastated
Calang, the capital of the district. Only about 30 per cent of
the town's population survived. Prior to the tsunami the town's
population was estimated to be between 9,000 and 12,000.
Satellite Image of
Banda Aceh taken on 2 Jan 2005
Meulaboh - A series of seven waves killed
about 40,000 people and destroyed port facilities and most parts
of Meulaboh, a town with a population of 120,000. About 50,000
people were left homeless.
Simeulue Island - Tsunami waves of about 5 meters
in height struck the island. Although Simeulue was close to the
earthquake's epicenter, suprisingly none of the island's 70,000
inhabitants were killed by the waves. Only five people died as
a result of the earthquake which destroyed about 90% of all buildings
along the coast. Apparently, the island rose which accounts for
the lower wave heights that were observed. Also, villagers on
the island had an awareness of the dangers of tsunamis, emphasized
by traditions memoralizing a destructive tsunami in 1907 that
had killed thousands of people.
Nias Island - The island was severely impacted
by the tunami which killed many people and severely damaged all
existing infrastructure. Original official accounts gave the
number of dead at 122, but these appear to be underestimates.
According to unconfirmed sources the waves killed 600 people
and the final death toll may ecxeed 1,000.
THAILAND
Hardest hit was the
Southwest coast of Thailand, particularly Phuket and the resort
areas of Phi Phi and Khao-Lak. It took about two hours for the
first of the tsunami waves to reach the resort of Phi Phi island.
The arrival
of the tsunami was heralded by a recession of the water which
exposed the sea bottom for considerable distance, including previously
submerged rocks. According to eyewitness reports, the first wave
arrived at about 10:30 am local time and it was about 4 meters
high. The second wave arrived about 2.5 minutes later and it
was 7 meters. The third about 11 meters.The waves destroyed all
beachfront hotels, bungalows and other structures at Phi Phi,
hurling boats and other floating objects . All electricity and
phone lines were cut. The hisghest reported wave was 11.6 meters
at Khao-Lak beach.
Thai Government
sources reported 5,313 deaths, 8,457 injuries and 4,499 missing,
including more than 1,000
foreign tourists.
Many of the missing are presumed dead. It is expected that these
estimates will be revised upwards.
INDIA
The estimated number
of casualties in India is 16,000, but at least 6,000 more are
missing. It is expected that the death toll will rise. Hardest
hit were the Andaman and Nicobar Islands which were close to
the tsunami generating area. Along India's southeastern coast,
several villages were swept away, and thousands of fishermen
at sea were missing. On the western coast of India' mainland,
hardest hit was the state of Tamil Nadu. Many hotels in India were influenced by the Tsunami and tourists had to be evacuated.
Andaman and Nicobar
Islands - The tsunami
hit hard the Andaman and Nicobar group which comprises of a total
of 572 islands of which 38 were significantly inhabited. Entire
islands have been The waves literally washed away some of these
islands, and there were reports that the island of Trinket had
split in two. The Great Nicobar and Car Nicobar were the worst
hit among all the southern Nicobar Islands because of their proximity
to the earthquake's epicenter and relative low topography. The
maximum tsunami wave reached a height of 15m. According to reports
one fifth of the population of the Nicobar Islands is said to
be dead, injured or missing. Chowra Island lost two thirds of
its population of 1,500.
The official death
toll is 812, but about 7,000 were reported as missing. The unofficial
death toll (including those missing and presumed dead) is estimated
to be about 7,000 and expected to rise. On 30 December 2004,
four days after the great earthquake, Barren 1 volcano on Barren
Island - located 135 kilometres (80 miles) northeast of the capital
Port Blair - erupted.
Andhra Pradesh - There was significant loss
of life and destruction. The affected districts were Krishna,
Prakasam, Nellore, Guntur, West Godavari and East Godavari.
Kerala - The tsunami killed many people
(official toll 168) and caused extensive destruction particularly
at Kollam (131 dead), Alappuzha (32) and Ernakulam (5) were also
affected.
Pondicherry - In the Union territory of Pondicherry,
the affected districts were Pondicherry (107 dead), Karaikal
(453 dead). The
latest official toll was 560. An estimated 30,000 people were
rendered homeless .
Tamil Nadu - The tsunami had a great impact
on the state of Tamil Nadu on India's mainland with entire coastal
villages destroyed. According to official reports the overall
death toll in the state was 7,793. The Nagapattinam district
had 5,525 casualties. The latest reported death toll at Velankanni
was 1,500. Kanyakumari district has had 808 deaths, Cuddalore
district 599, the state capital Chennai 206 and Kancheepuram
district 124. The death tolls in other districts were Pudukkottai
(15), Ramanathapuram (6), Tirunelveli (4), Thoothukudi (3), Tiruvallur
(28), Thanjavur (22), Tiruvarur (10) and Viluppuram (47). The
death toll may be significantly higher as many are still missing.
The nuclear power
plant at Kalpakkam was shut down after sea water rushed into
a pump station. No radiation leak or damage to the reactor was
reported.
SRI-LANKA
The first of the tsunami
waves took a little over two hours to reach Sri-Lanka. A clock
on the western side of Sri Lanka at Colombo stopped at 9:20 in
the morning, so the tsunami travel time to Colombo (first wave)
must have been about 2 hours and 20 minutes. Sri-Lanka's south
and east coasts were hardest hit. More than 50,000 people lost
their lives - mostly children and the elderly. Most of them (more
than 1,200) were in the eastern district of Batticaloa.
At Trincomalee in
the northeast, the tsunami reached more than 2 km (1.25 mi)
inland killing about 800 people. In the neighboring Amparai district
alone, more than 5,000 people died. The naval base at Trincomalee
was reported to be submerged. About 3,000 more people died in
Mullaitivu and Vadamaradchi East. A train, known as the "Sea
Queen", while traveling between Colombo and Galle, with
1,600 passengers on board, was struck and derailed by the tsunami.
Only about 300 of the passengers survived. More than one and
a half million people were displaced in Shri-Lanka and the death
toll is expected to rise.
MALAYSIA
Despite Malaysia's
proximity to the tsunami generating area, the impact of the waves
was not as severe as in other countries in the region or countries
thousands of kilometers away. Malaysia was partly sheltered by
Sumatra and the tsunami waves attenuated somewhat in the Straits
of Malacca. However, there were numerous deaths and destruction
reported. The country's worst affected areas were the northern
coastal areas and the outlying islands. Hardest hit were Penang,Kedah,
Perak, Selangor and Langkawi. It was reported that the red flag
warning system used by lifeguards on beaches in some resort areas
in Penang helped reduce fatalities there. Houses in fishing villages
along coastal areas were damaged in Batu Maung and Bayan Lepas
in Penang. Coastal areas in Peninsular Malaysia e.g. 13 villages
in Kuala Muda, Kedah and Kuala Triang in Langkawi island were
also affected. About a quarter of the boats anchored in Rebak
and Telaga harbour in Langkawi were damaged. The number of deaths
currently stands at 68 with 52 in Penang, 10 in Kedah, 3 in Perak
and 1 in Selangor. Another 6 are missing.
MYANMAR
The mainland of Myanmar
was somewhat sheltered from the full impact of the tsunami by
the numerous offshore islands. Also the approximate North-South
orientation of the tsunami generating area, resulted in waves
of lesser amplitude traveling northward. Still the tsunami caused
numerous deaths and destruction in Myanmar. Reportedly 90 people
were killed, but eyewitnesses estimate that more than 600 people
have died. 788 buildings have been reported as damaged or destroyed.
30,000 people were displaced.
MALDIVES
The waves flooded
two-thirds of Male, the capital. Hardest hit were the outlying
low-level atolls. Some other low lying islands were completely
submerged, including some where major resorts were located. Preliminary
reports stated that the tsunami killed 82, that 26 are missing,
and that there was extensive destruction. However, communications
with remote islands were down and the death toll will probably
rise. Thirteen islands have been abandoned because all buildings
were destroyed and the fresh water supply was contaminated by
the sea.
SOMALIA
The tsunami waves
traveled a distance of 4,500 km (2,800 miles) and struck Somalia
on Africa's east coast. The height of the waves remains to be
determined.
Hardest hit was the
semi-autonomous Puntland area, particularly the region between
Hafun in the Bari region and Garacad in the Mudug region. The
narrow and low-lying peninsula of Hafun, 1150km (715 miles) northeast
of Mogadishu, was particularly devastated.
The waves caused devastation
in the Puntland area , striking the town mosque of Brava and
destroying the villages of Beyla, Garacad, Muduy and Nugaal.
Other coastal areas including Lower Juba were also affected.
At Kulub and Hurdiye, all the fishing boats were either lost
or destroyed.
According to a UN
report 1,180 homes and 2,400 boats were destroyed. The main bridge
which connects Hafun to the mainland was washed away. Te flooding
rendered freshwater wells and reservoirs unusable.
A total of 298 people
lost their lives and 50,000 more were displaced. The final death
toll is expected to rise as there are many more missing.
AUSTRALIA
No casualties were
reported. The tsunami caused minor flooding along the northwestern
coast and rurging activity was reported along Western Australia.
At Geraldton, 425 km north of Perth, several boats were
ripped from their moorings. At Busselton, 325 km south of
Perth, a father and son in a boat were washed out to sea, but
were subsequently rescued. Swimmers at Christmas Island were
sucked 150m out to sea by the tsunami. Subsequently they were
carried safely back to shore.
BANGLADESH
The tsunami's impact
was relatively mild. The waves killed two children and capsized
a tourist boat.
KENYA
There was minor damage.
One person was reported drowned at Watamu, near Mombasa.
MADAGASCAR
The tsunami waves
ranged from 1.6 meters to 10 meters along the souteastern coastal
areas near the towns of Manakara, Sambava and Vohemar. There
was considerable destruction - leaving about 1,000 people homeless
- but no deaths were reported.
MAURITIUS
Waves completely submerged
a village in the north of the island. There have been no reports
of casualties.
OMAN
The tsunami hit the
coastline but no casualties were reported.
REUNION ISLAND (France)
The tsunami sunk over
200 boats and caused considerable damage to port facilities.
SEYCHELLES
The tsunami killed
three people. Seven more people are missing. The waves destroyed
a major bridge in Port Victoria.
SOUTH AFRICA
A sea level rise of
about 2-3 meters was reported for KwaZulu-Natal and Eastern Cape.
One person was reported killed at Blue Horizon Bay near Port
Elizabeth. A boy drowned in the Quinera River at Gonubie.
TANZANIA
The tsunami waves
killed ten people. An unknown number of people are still missing.
An oil tanker run run aground in Dar es Salaam harbor, damaging
an oil pipeline.
More information on
the tsunami effects in the Bay of Bengal and other areas of the
Indian Ocean will be provided with a later update.
Tsunami
Wave Heights and Tsunami Travel Times
Tsunami waves varied
in height. Maximum reported height was reported as being 10.5
meters, A detailed report on tsunami wave distribution for different
of the stricken areas througout the Indian Ocean is being compiled
from reports of eyewitnesses and other sources. A list of tsunami
wave heigts as recorded by tide stations will be provided. However,
most of the tide stations that recorded the tsunami are at distant
locations. It is not known at this time whether any tide gauge
stations closer to the tsunami generating area recorded the tsunami.
An effort is being made to locate such records from tide stations
that were not destroyed by the tsunami - if such stations exist,
Tsunami travel times
for different areas in the Bay of Bengal and throughout the Indian
Ocean are being compiled. Travel times of the first tsunami wave
after the earthquake: Sumatra 10 minutes ,Thailand: 1 Hour, Sri
Lanka: 2 hours, India: 2 Hours, East Africa: about 7 Hours.
Map of the Nicobar
and Andaman Islands (Not to Scale)
Peninsula
of Acep Meulaboh in Northern Sumatra - one of the hardest hit
by the tsunami areas.
Lessons Learned
There were many lessons already
learned from this tragic event in Southeast Asia. Many more lessons
will be learned in the near future as this tragedy unfolds and
reveals the many failures to value and protect human life in
this neglected region of the world. Indeed a bitter lesson was
already learned - that great earthquakes and destructive tsunamis
do occur in this region.
Tsunami Destruction
at Banda Aceb, Northern Sumatra (photo of unknown origin )
The magnitude of the
tsunami disaster could have been mitigated with a proper disaster
preparedness plan and a functioning early warning system. A warning
perhaps could not have been of much help in the immediate tsunami
generating area of Sumatra and the Nicobar and Andaman islands,
because the tsunami waves reached the shore very quickly. However
the strong shaking by the earthquake should have been nature's
warning for the local residents that a tsunami was imminent and
they could have run to higher ground to save their lives. A simple
program of public education and awareness of the potential hazard
could have saved many lives in the immediate area.
![](tsu2004IndoThaiKhaoLakBeach.jpg)
Tsunami destruction
at Thailand's Khao Lak Beach ((photo of unknown origin )
For the more distant
coastlines of India, Shri-Lanka, and other locations in the Bay
of Bengal and the Indian Ocean, there was ample time to issue
a warning - if only an early warning system existed for this
region of the world and if there was a way of communicating the
information to the coastal residents of threatened areas. No
such warning system exists at the present time - the lack of
disaster awareness or preparedness is appalling. It was reported
that in many areas where there was extensive losses of lives,
when the water withdrew before the arrival of the tsunami, the
local residents went to the shore to collect stranded fish, instead
of running to higher ground. People were totally unaware of the
imminent danger. A simple educational program on hazard awareness
could have prevented the extensive losses of lives - particularly
of children. One third of those that perished were children.
The Tsunami Warning
System which operates in the Pacific Region does not have the
capability of extending a warning to countries bordering the
Indian Ocean. Although the magnitude and location of the eartquake
were quickly determined, there were no wave sensors in the area
to confirm the generation of a tsunamni. Although both Indonesia
and Thailand are members of the Pacific Tsunami Warning System
network, they do not operate wave sensors on the western coast
of their islands or territories.
India and Shri Lanka
are not members of the international Warning System in the Pacifc
and they have not shown interest in joining any regional early
warning system. An erroneous belief has persisted that tsunamis
do not occur frequently enough to warantee participation into
a regional tsunami warning system. Local government authorities
in the region did not even have a plan for disseminating warning
information to the threatened coastlines - even if a warning
had been provided. There was not even a basic educational plan
for disaster preparedness. It should be obvious that such a program
is necessary to prevent similar tragedies in the future.
LINKS TO PAST
AND RECENT EARTHQUAKE AND TSUNAMI DISASTERS IN SOUTHEAST ASIA
AND THE SOUTHWEST PACIFIC OCEAN
Tsunamis
of the Indian Ocean
INDONESIA
1883 : Near and Far-Field Effects of Tsunamis Generated by the
Paroxysmal Eruptions, Explosions, Caldera Collapses and Slope
Failures of the Krakatau Volcano in Indonesia, on August 26-27,
1883
INDIA 2002 - The Earthquake of January 25, 2001
in India
PAPUA
NEW GUINEA 1998 - he Tsunami of 17 July 1998 in Papua -New Guinea
INDONESIA
1977 : The Earthquake and Tsunami of August 19, 1977
INDONESIA
1883 : The Great Tsunami of August 26, 1883 from the Explosion
of the Krakatau Volcano ("Krakatoa")
PILIPPINES
1976 - The Earthquake and Tsunami of August 16, 1976 , in the
Philippine Islands
VANUATU
1999 - The Earthquake and Tsunami of November 26, 1999 in Vanuatu
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