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Prior to the tsunami of 26th December 2004, triggered by the most powerful earthquake in the world for the last forty years, there have been no major natural disasters in Thailand for generations.
The tsunami was such a tragic and unforeseen event, it almost defies comprehension.
In actual fact, on the basis of subsequent analysis of additional seismograms from around the world, scientists have determined the earthquake's magnitude to be 9.3 and not 9.0, as originally estimated.
Therefore, the calculated energy release was three times larger than originally thought. The revised estimate makes this quake to be the second largest ever instrumentally recorded by modern seismic instruments.
(The largest earthquake ever recorded, which measured 9.5, was in Chile on May 22, 1960).
This great tsunamigenic earthquake had a focal depth of approximately 30 km (originally reported as being only 10 km).
In addition, the earthquake had the largest ruptured fault (1200 km - essentially from Sumatra to the Andaman islands) ever observed, and covered a time span along the fault of 500 seconds (just under 9 minutes).
Initial estimates of the magnitude of the earthquake were grossly underestimated which unfortunately shows the limitations of conventional magnitude estimators for really great earthquakes.
A Harvard magnitude reading of 9.0 was only available after a few hours. And a final magnitude calculation of 9.3 was determined weeks later (by free oscillation calculations).
And so this prevented (in part) a timely alert of the coasts at risk, and highlights the need for a fast non-saturating magnitude recorder for large earthquakes. This is being worked on.
But at the time, estimators for earthquakes greater than 8.0 (and also slow-rupture earthquakes) came up with a somewhat inaccurate figure.
Accordingly the probability of a tsunami (and its strength) were also underestimated.
The critical magnitude to generate tsunamis is often regarded as about 7.5.
The maximum tsunami wave height at Khaolak has been reported to be 11.6 meters.
Average wave heights were as follows:
Khao Lak: 6 - 10 meters
Phuket (west coast): 3 - 6 meters Phuket (east coast): 3 meters
Phi Phi islands: 4.5 - 6.0 meters
The tsunami at KhaoLak was exceptionally strong. It has been suggested from field survey reports that a lot of tsunami energy was trapped at the nearby Similan islands, and this energy
headed east to Khaolak.
In contrast to Phuket, which was relatively unscathed due (maybe) to the topology of the island and it's bays, the Andaman coastline from Poseidon beach, through KhaoLak proper, Khuk Khak beach, the Pakarang peninsular, Bangsak, Baan Namken, and upto within ten kilometers of Takuapa,
suffered quite extensive damage. The waters breached highway 4 in a few places. In particular, Bang Niang beach, Khuk Khak beach. the Pakarang peninsular and Bangsak beach were quite badly hit.
The destruction to buildings including internationally acclaimed hotels was very severe. (And in terms of the general landscape, in the very short term at least, only the most robust of vegetation and trees were able to withstand the force of the waves
and the after-effects of the salt water.)
So very very sad and painful for so many people ...
At 00.59 hrs GMT on 26th December 2004, a 9.3 magnitude earthquake tore apart the seafloor 160 km off the northwest coast of Sumatra, at part of the boundary (the 1,200 km Andaman-Sumatran trench) of two of the world's mighty tectonic plates. The lower plate, which carries India, (and which is part of the bigger Indo-Australian plate) has been moving slowly north/northeast, at a speed
which has been compared to the growth of our fingernails (2 inches per year). It is continually being forced (subducted) beneath the upper plate (known as the Burma plate which is a tongue shaped part of the bigger Eurasian plate carrying most of South East Asia). The plates meet at oblique angles, which means the movement is not a smooth, frictionless glide but a torturous buildup of stresses that can result in dramatic perpendicular slips.
Before the fault ruptured, the edge of the upper Eurasian plate was actually being dragged downward by the descending Indo-Australian plate.
Released by the rupture of the fault, the edge of the upper plate sprang back up, lifting the ocean floor and setting off the tsunami. The fault slipped by as much as 20 metres in a few places.
This type of earthquake is very powerful and is referred to as a megathrust. Over 100 years of accumulated stress was released by the earthquake and billions of tonnes of seawater was subsequently displaced to form the tsunami.
An exceptionally long (estimated at 1,200 km) faultline slipped typically about 10 - 15 m along the subduction zone where the India Plate dives under the Burma Plate. The slip took place in two phases over a period of several minutes.
It is further estimated that 30 km³ (7 cubic miles) of water was displaced. The tsunami waves radiated outwards along the entire 1,200 km length of the rupture, as opposed to originating from a point source.
Due to the complex rupturing of the sea floor, some tsunami waves effectively travelled with the crest first whilst others travelled with the trough first. When a trough reaches the coastline, it causes the sea to withdraw and disappear from the beaches. This is one of the classic warning signs of an approaching tsunami.
Tragically many people were unaware of this sign, and were attracted by the fish left flapping on the sand. Minutes later the crest waves would arrive and the full force of the tsunami caused a thousand tonnes of water to crash down on each metre of beach.
Although not helpful to people on the beach, it has been reported that elephants seemed to sense that something was coming. They began acting strangely, stamped the ground and tugged at their chains until they broke away and headed to the hills. Elephants have special bones in their feet that enable them to sense seismic vibrations long before humans can.
By all accounts, the regional disaster centres of Takuapa and Phuket performed wonders under the circumstances, and the caring and helpful nature of the fantastic Thai people shone through quite strikingly.
The Thai army and medics did a truly excellent job in setting up and administering relief centres, donation centres, and temporary accomodation.
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Photo above left:
Fishing boat washed up in the middle of the destroyed village of Baan Namken
Photo above right:
Police patrol boat in the jungle, east of route 4, 1 km inland at Baan Niang Khaolak
Photo below:
Royal Thai Navy frigate (KraBuri) beached at Thap Lamu pier, south of Khaolak
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According to some unofficial estimates, it could take upto December 2005 before Khaolak is again completely restored to it's original charm and potential. The local Thai people who contribute so much to making
your vacation such a joy, and who have lost family members, friends, and their livelyhood, naturally hope this is a conservative estimate . Your visit would be so welcome.
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Tsunami Early Warning System
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Patong beach Phuket is the first of all Andaman resorts to have a newly-installed world-class emergency warning system. It emits a 121-decibel alert that can be heard 1,500 meters away.
Warnings will be issued in several languages.
The system, is linked to the Nonthaburi-based National Disaster Warning Center (NDWC).
The Patong system has been installed by Bangkok-based Ele Sat Engineering, using communications equipment from Swedish company Kockum Sonics and an Inmarsat satellite system.
In addition, the Similan islands tsunami detection station on Koh Mieng is now operational. Eight other such island-specific detection centres will be in operation by the end of 2005 and will include:
Tapao Noi and Racha Noi islands (Phuket province), Sikow island (Trang), Tarutao island (Satun), and the Surin Islands (Phang Nga).
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Basically about 80% of the tsunami early warning system, including technology to send alerts to mobile phones and television and radio stations, as well as watchtowers equiped with sirens, will be in place by May 2005
for all six coastal provinces affected by the Decemeber 26th 2004 tsunami.
The full and complete system with special sensors and detector bouys (1,100 km off the Andaman coast near the Nicobar Islands), was finished by the end of 2005 and will be installed by late November 2006 by a joint Thai - USA team.
The bouys will
determine precisely whether a tsunami is imminent, and give about 1 hour's notice. This is a US-made network system formally known as the Deep Sea Tsunami Detection Equipment.
In the meantime, and in parallel to the ongoing effort, Thailand will also rely on earthquake measurement data to guage the threat of possible tsunamis.
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Whilst it is almost impossible to predict exact dates, location and magnitude of earthquakes, it is much easier to predict tsunamis and their extent as a result of such earthquakes.
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A tsunami is a wave train, or series of waves, generated in a body of water by an impulsive disturbance that vertically displaces the sea water. Earthquakes, landslides, volcanic eruptions, explosions, and even the impact of meteorites, can generate tsunamis.
In particular, relatively shallow earthquakes (less than 30 km) beneath the sea can generate tsunamis.
Needless to say, tsunamis can savagely attack coastlines.
Tsunamis are vastly different to the typical (wind-generated) waves, which we see at a coastal beach. Technically they are characterized as shallow-water waves, but with long periods and wave lengths. The wind-generated waves have a period of about 10 seconds and a wave length of 150 m. A tsunami, on the other hand, can have a wavelength in excess of 100 km and period of the order of one hour.
A shallow-water wave has a noteable ratio between the water depth and its wave length.
Shallow-water waves move at a speed that is equal to the square root of the product of the acceleration of gravity (9.8 m/s/s) and the water depth. This implies that if the typical water depth in the ocean is about 4000 m, a tsunami travels at over 700 km/hr.
Because the rate at which a wave loses its energy is inversely related to its wave length, tsunamis not only propagate at high speeds, they can also travel great, transoceanic distances with limited energy losses.
Thus even after they have travelled vast distances, tsunamis reach distant coastlines with almost as much power as they had when they left the immediate earthquake centre.
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As a tsunami leaves the deep water of the open ocean and travels into the shallower water near the coast, it transforms.
A tsunami travels at a speed that is related to the water depth. Thus, as the water depth decreases, the tsunami slows. However the tsunami's energy flux, which is dependent on both its wave speed and wave height, remains nearly constant.
Consequently, as the tsunami's speed diminishes as it travels into shallower water, its height grows.
Because of this shoaling effect, a tsunami, almost imperceptible at sea (being only 30cm above the surface), may grow to be several meters or more in height near the coast. When it finally reaches the coast, a tsunami may appear as a rapidly rising or falling tide.
So as a tsunami approaches shore, it begins to slow but grow in height.
Just like other water waves, tsunamis begin to lose energy as they rush onshore - part of the wave energy is reflected offshore, while the shoreward-propagating wave energy is dissipated through bottom friction and turbulence.
Despite these losses, tsunamis still reach the coast with tremendous amounts of energy.
Tsunamis may reach a maximum vertical height onshore above sea level, often called a runup height, of 10, 20, and even 30 meters.
Because tsunamis have very long wavelengths they come ashore more like a long lasting flood wave rather than the breaking surf usually seen at the beach.
The diagram illustrates the difference between tsunamis and wind waves when they come ashore.
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Let's look at it another way. If you throw a stone in a pond you create a series of concentric ripples. A tsunami is just like those ripples, except the disturbance that sets them in motion is of a much greater magnitude.
However the above analogy is limited because the pond waves loose energy quickly and disperse.
The worst tsunami waves are different. Not only do they have enormous energy, but they are "long waves" in the sense that the wavelength is many times greater than the ocean depth. All such waves travel at nearly the same speed, so that the energy doesn't spread so much, and they can survive over thousands of miles.
The usual tsunami-maker is the buckling of the seafloor caused by an earthquake, several kilometers beneath the seabed.
In the instant after the quake, the shape of the sea surface mirrors the contours of the now buckled seafloor below. But, just as quickly, gravity acts to return the sea surface to its original shape. As the rumpled sea flattens out, ripples race outward. A tsunami is born.
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Can you help? Volunteers required
The Tsunami Volunteer Centre in KhaoLak Nature Resort, PhangNga is looking for a large number of volunteers - committed down-to-earth people who can tolerate tough conditions.
Skills include the following:-
IT support
Web Site designers/developers
Language translators (written) - Thai/English
Language interpreters Thai/English
Volunteer coordinators
Special projects staff
Fund-raising staff
Please visit the volunteer web site for further information
* www.tsunamivolunteer.net *
Email: info@TsunamiVolunteer.net
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Relief and Cleanup Operations (January 2005)
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The relief operation has been quite heroic and the cleanup operation is proceeding rapidly. The entire area is very busy with activity.
All along highway 4 and the Pakarang peninsular, new electricity poles were erected within days of the disaster. Feeder cables reach the temporary accomodation, constructed by the Royal Thai army.
There are endless numbers of pickup trucks (belonging to residents, visitors, Thais, and foreigners) arriving in Khaolak and its environs, and bringing basic commodities such as rice, bottled water and cooking pots to the relief operations
drop off points. Many of the foreigners travel up from Phuket. So many concerned people have been helping with their own small relief efforts.
There have been numerous visits to the region from overseas aid foundations, and a great many dignatories from around the world including two USA ex-presidents.
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Heavy machinery (diggers and excavators) are in action everywhere. Most damaged hotel structures have already been cleared, and a good deal of the rubble and broken cars have been taken away;
but there are still some neat piles, scattering the landscape, awaiting clearance. Recycling is an important part
of the operation. For example, in addition to metal, the destroyed concrete remains of buildings will be recycled by smashing them into small
fragments, which will then be used for foundations of future construction.
An ackwardly beached Marine Police boat, well over one kilometer inland at the edge of the jungle to the east of highway 4 at Bang Niang, is becoming a
bit of an icon; as if there is not enough other evidence of the force of the tsunami waves.
All hotel information on this website has been updated as to current status. Although there was severe damage to many hotels, a few are now re-opening. Please refer to our Accomodation section.
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