Date Source Location Estimated
Lives Lost
29 Nov 1975 Hawaii, USA 2
17 Aug 1976 Philippines *8,000
19 Aug 1977 Indonesia 189
18 Jul 1979 Indonesia 540
12 Sep 1979 New Guinea 100
12 Dec 1979 Colombia 500
26 May 1983 Sea of Japan 100
2 Sep 1992 Nicaragua 168
12 Dec 1992 Flores Is., Indonesia 1,000
12 Jul 1993 Okushiri Is., Japan 230
3 Jun 1994 Java, Indonesia 222
4 Oct 1994 Shikotan Is., Russia 11
14 Nov 1994 Philippines 74
9 Oct 1995 Manzanillo, Mexico 1
1 Jan 1996 Sulawesi, Indonesia 9
17 Feb 1996 Irian Jaya, Indonesia 110
23 Feb 1996 Peru 12
17 July 1998 Papua New Guinea 2,500
* May include earthquake casualties

Fiction: Tsunamis are giant walls of water.
Facts: Tsunamis normally have the appearance of a fast-rising and fast-receding flood. They
can be similar to a tide cycle occurring over 10 to 60 minutes instead of 12 hours. Occasionally,
tsunamis can form walls of water, known as tsunami bores, when the waves are high enough
and the shoreline configuration is appropriate.
Fiction: A tsunami is a single wave.
Facts: A tsunami is a series of waves. Often the initial wave is not the largest. The largest wave
may occur several hours after the initial activity starts at a coastal location. There may also be
more than one series of tsunami waves if a very large earthquake triggers local landslides. In
1964, the town of Seward, Alaska, was devastated first by local tsunamis caused by submarine
landslides resulting from the earthquake and then by the earthquake’s main tsunami. The local
tsunamis began even as people were still experiencing the shaking. The main tsunami,
triggered at the site of the earthquake, did not arrive for several hours.
Fiction: Boats should move to the protection of a bay or harbor during a tsunami.
Facts: Tsunamis are often most destructive in bays and harbors, not just because of the waves
but because of the violent currents they

• If your community is at risk, build tsunami evacuation routes and publicize their
locations. Post signs directing people to higher ground away from the coast.
• Review land use in tsunami hazard areas so no new critical facilities, such as hospitals
and police stations; high-occupancy buildings, such as auditoriums or schools; or
petroleum-storage tank farms are built where there is a tsunami hazard. Consider
relocating existing critical facilities outside the tsunami hazard area when opportunities
arise, or at least explore ways to reinforce facilities and structures, such as critical
bridges needed for evacuation. Tsunami damage can be minimized through land use
planning, preparation, and evacuation.
• Ask your local newspaper or radio or television station to:
-Do a series on the dangers of tsunamis and floods.
-Do a story featuring interviews with local officials about land use
management and building codes in floodplains.
-Highlight the importance of staying informed about local
conditions.
-Run public service ads about how to protect lives and property in
a tsunami.
Help the reporters to localize the information by providing them with the local emergency
telephone number for the fire, police, and emergency medical services departments
(usually 9-1-1) and emergency numbers for the local utilities and hospitals. Also provide
the business telephone numbers for the local emergency management office, local
American Red Cross chapter, and state geological survey or department of natural
resources.
• Work with officials of the local fire, police, and emergency medical services departments;
utilities; hospitals; emergency management office; and American Red Cross chapter to
prepare and disseminate guidelines for people with mobility impairments about what to
do if they have to evacuate.
• Periodically inform your community about local public warning systems.
• Interview local officials and insurance companies about the types of insurance that cover
flood-related losses. Include information on the economic effects of disaster.

Tsunami risk reduction requires a comprehensive approach
consisting of warning guidance, risk assessment, and
preparedness and education. An effective tsunami warning
system requires activities in all components. ITIC’s mitigation
program is directed towards coastal residents, their national
and local officials, school teachers, mass media, policy makers,
and the general public. It includes training classes, lectures,
community briefings, and media broadcasts. ITIC materials
include informational booklets, textbooks, lecture materials,
audio-visual aids, posters, photographs, television and radio
materials, and other publications. A prepared and aware
public will know immediately how to respond when a tsunami
emergency is declared. ITIC works with governments and
civil society organizations to implement community-based
mitigation programmes that will reduce tsunami impacts
and save lives.
Under ITIC's ITP-Hawaii Programme on tsunami warning
and mitigation systems, scientists, engineers, and tsunami
programme officials can spend up to three weeks in Hawaii
at ITIC, PTWC, and with local civil defense agencies
learning about tsunamis,operations of tsunami warning
systems, risk assessment, and education and preparedness
programmes. ITIC also conducts the ITP-International
Programme, which annually visits Member States to
provide in-country capacity assessments, and
tsunami awareness and technology training

Recently, numerous congressional inquiries have asked about the possibility of
tsunamis occurring in U.S. coastal areas; the extent to which these areas are currently
monitored; how tsunamis can be detected; and whether there is a national capacity
to issue evacuation warnings for tsunamis. These concerns stem from the December
26, 2004, tsunami triggered by an underwater earthquake off the west coast of
northern Sumatra in Indonesia. That earthquake was measured at Mw 9.0.1 The
ensuing tsunami devastated many coastal areas around the northern Indian Ocean,
and caused loss of life and damages in other areas. International disaster agencies
currently estimate that at least 150,000 people lost their lives to the tsunami.
The National Oceanic and Atmospheric Administration (NOAA) of the
Department of Commerce and various international science agencies have indicated
that there were few, if any, tsunami early warning systems monitoring the Indian
Ocean on December 26, 2004. However, nations bounded also by the Pacific Ocean,
including Australia and Indonesia, had tsunami early warning systems monitoring the
Pacific shores where they perceived a threat.2 Because of the lack of infrastructure
to receive tsunami warnings rapidly, some have pointed out that for people on
Indonesia’s Indian Ocean shores, emergency communications were useless in many
cases.
Although most deadly tsunamis have occurred historically in the western Pacific
Ocean, there are examples of recoded events in the Atlantic. In 1692, a tsunami
generated by massive landslides in the Atlantic Puerto Rican Trench reached
Jamaica’s coast, causing an estimated 2,000 deaths. In 1775, a tsunami struck in the
eastern Atlantic Ocean on the coast of Portugal, killing an estimated 60,000 people.
More recently, in 1929, a tsunami generated in the Grand Banks region of Canada hit
Nova Scotia, killing 51.
On January 5, 2005, the House Science Committee, House Coastal Caucus, and
House Oceans Caucus co-sponsored a briefing organized by the U.S. Geological
Survey (USGS) of the Department of the Interior. One purpose of the briefing was
to consider the possible implications of the Indian Ocean tsunami for the United
States. Experts from USGS and NOAA delivered presentations on the circumstances
surrounding that tsunami disaster, and discussed current capabilities for monitoring,
detection, and early warning around the globe.4

Fulfi lling this tsunami-specifi c implementation plan will create a more disaster-resilient America. Specifi cally:
Relevant hazards are recognized
and understood. Coastal
communities will be better able
to prepare for the tsunami
threat by understanding the
characteristics of both distant
and local tsunami sources and
potential tsunami frequency.
Continued broad scientifi c
research will increase our understanding
of tsunami processes
and impacts, and
will develop more effi cient
and effective risk assessment
and risk communication
prediction, preparedness,
mitigation, and warning
measures.
Communities at risk know when
a hazard event is imminent.
More accurate and timely
warnings will be disseminated
with greater timeliness.
Outreach and education will
focus on appropriate actions
in response to local and
distant tsunamis.
Individuals at risk are safe from hazards. Preparedness will be achieved through the increased TsunamiReady
communities that have response plans, enhanced communications, and heightened awareness of their citizens.
As a result, fewer lives will be lost, economic losses will be less, and recovery periods will be shortened. With a
better understanding of the threat and impacts, better, sustained actions can be taken prior to the occurrences of
the event.
Disaster-resilient communities experience minimum disruption to life and economy after a hazard event has passed.
Due to effective land-use planning, prepared ness, and warning, a tsunami could strike and not harm the built
environment or cause loss of life.

GRAND CHALLENGE #1: Provide hazard and
disaster information where and when it is needed.
Improve tsunami and seismic sensor data and
infrastructure for better tsunami detection;
Enhance tsunami forecast capability along our
coastlines (Pacifi c, Atlantic, Caribbean, and Gulf of
Mexico) by increasing the number of Deep-ocean
Assessment and Report of Tsunamis (DART) buoys,
tide gauges, and seismic sensors feeding real-time
data into on-line forecast models;
Develop standardized and coordinated tsunami
hazard and risk assessments for all coastal regions
of the United States and its territories;
Encourage data exchange and interoperability
among all regional tsunami and all-hazard warning
systems, coordinated by the Intergovernmental
Oceanographic Commission’s sub-Commission for
the Caribbean.
GRAND CHALLENGE #2: Understand the natural
processes that produce hazards.
Develop improved and sustained monitoring and
research of both the generating mechanisms and
the physical characteristics of the tsunami and
more accurate description of the sites at risk;
Research and better understand the protective role
coastal marshes, coral reefs, barrier islands, and
other coastal features play during a tsunami;
Conduct an annual review of the status of tsunami
research and develop a strategic plan for tsunami
research in the United States.
GRAND CHALLENGE #3: Develop hazard mitigation
strategies and technologies.
Develop engineering advancements for sea walls
and energy dissipaters that will minimize impact;
Develop coastal management plans that will
protect coastal features that act as natural energy
dissipaters to minimize the tsunami impact;
Promote development of model mitigation
measures and encourage communities to adopt
construction, critical facilities protection, and landuse
planning practices to reduce the impact of
future tsunamis.
GRAND CHALLENGE #4: Reduce the vulnerability
of infrastructure.
Develop risk assessments and inundation models to
inform the location of lifelines, hospitals, schools,
power plants and utilities, fi re and police stations,
and equipment away from the risk area or harden
those structures for adequate protection from the
assessed tsunami risk.
GRAND CHALLENGE #5: Assess disaster resilience.
Develop improved and standardized assessments
of societal, economic, and environmental
vulnerability to, impacts of, and a more robust
response and recovery capacity related to tsunami;
Develop effective land use plans based on risk
assessments and better topographic and
bathymetric maps to predict inundation levels
and possible effects;
Improve use of risk assessment tools, mitigation
practices, evacuation plans, and timely and
accurate warnings to promote risk-wise behavior by
decision makers and individuals.
GRAND CHALLENGE #6: Promote risk-wise behavior.
Increase outreach to all communities at risk to raise
awareness, improve preparedness, and encourage
the development of tsunami response plans;
Ensure interoperability between the United States’
national system and other regional tsunami
warnings systems;
Provide technical expertise and assistance, as
appropriate, to facilitate the development and
enhancement of the international tsunami and
all-hazard warning systems, including for the
Indian Ocean;
Employ geographically specifi c communication and
dissemination strategies for extended warnings and
probabilistic forecasts based on improved social
science research into individual response;
Increase the effectiveness of warnings and
evacuations through informed community
planning and annual drills.

As time passes, the saltwater that has infiltrated, through the soil surface or from water bodies and wells,
moves through the groundwater in a general downward and lateral direction towards the coast (or maybe
towards a lagoon or inland water body). Eventually, and with a continued influx of rainwater, the saltwater
will be suppressed, mixed, diluted and transported to the open water. These are natural processes that
occur and allow that over the longer term, the aquifer can recover and return fresh.
9
The International Groundwater Assessment Centre (IGRAC) made some preliminary estimations of the
time required to naturally rehabilitate the coastal aquifers3. Using a numerical simulation model and applying
some simplifying assumptions of the land-groundwater system it was estimated that it would require a
couple of years to obtain pre-tsunami salt concentrations in the aquifer, under conditions prevailing in the
Maldives, which is an archipelago to the west of Sri Lanka, also impacted by the tsunami. Some of the
uncertainties associated with this simulation are related to:
1. Insufficient knowledge of actual conditions. Some of the factors/parameters that have not been
assessed based on actual conditions and measurements, and may significantly influence the results
are:
• The hydraulic conductivity of the aquifer, which determines the rate at which water moves through
the sediments
• The depth of the aquifers, i.e. if there is an impermeable layer restricting the freshwater lens
• The influence of actual rainfall occurring in the affected areas
• The amounts and patterns of pumping
2. Furthermore, some important processes/phenomena may not have been incorporated sufficiently:
• The infiltration from stagnant water bodies has not been included
• The possible disruption of the freshwater lens due to an underground pressure wave has not been
included
• The possible slow leaching of the saltwater in the aquifer due to low permeable zones, or so-called
double-porosity characteristics

While tsunamis usually occur in the Pacifi c Ocean, all low-lying coastal areas can be struck by
tsunamis. In North America, higher risk areas have warning systems in place, and clearly marked
evacuation routes.
The best advice for surviving a tsunami is to get as far away from its destructive force as possible.
• If you are caught on land near the coast during an earthquake, move as quickly as possible away
from the water and, if possible, up higher ground.
• If you are on open water in a boat, move as quickly as possible to deeper water.
Most buildings will not provide a great deal of protection from tsunamis. Some may collapse, others may fl ood
trapping you inside.
This basic knowledge passed down from generation to generation
saved whole villages of the Moken people during the
recent Indian Ocean tsunami. Moken Elders tell stories of the
Laboon, the wave that eats people. They say that before the
wave arrives, the earth shakes, birds and bugs fall silent, water
animals move deep into the ocean and land animals move to
higher ground, then the water recedes. As the story goes, when
these signs occur all the people must abandon their homes
and move to higher ground as quickly as possible, because
the water will return quickly in quantities bigger than can be
imagined. As far as any one can tell, only one Moken died in
the recent tsunami.
What is lifesaving knowledge in your community?

Since predicting earthquakes is so hard, tsunami protection relies
on warning systems. These warning systems combine seismographs
with water-based sea level gauges, sea fl oor pressure
sensors and satellite communications, so that when a tsunami
causing earthquake occurs warnings can be provided to coastal
areas as quickly as possible.
How fast can a tsunami reach land?
Courtesy National Oceanic and Atmospheric Agency (NOAA)
This map, from the Pacifi c Tsunami Warning Systen,
shows approximate travel times for a tsunami
generated by an earthquake near Hawaii.
Not all countries are served by warning systems, and even those that are often have trouble getting warnings out to
small or remote communities. In addition, while warnings help save lives, they do not protect land, buildings and
vegetation from the power of massive waves. So, in some places people have taken actions to develop some protection
from the force of the sea. Sea walls, are usually built to prevent coastal erosion, however they might in some
instances help dissipate energy in tsunami waves so that less destruction occurs on land. Natural barriers to water
also help. In the December 2004 tsunami, communities protected by mangrove forest suffered less damage than
those completely exposed to the wave.
The Huu-Ay-Aht people remember the stories the Elders tell about the great wave that nearly wiped them out 300
years ago. They also remeber the tsunami of 1964; their community wasn’t built then, but the nearby town of Bamfi
eld suffered a lot of damage. They are taking steps to protect both themselves and their homes. They have been
negotiating with the Government of British Columbia to move their entire community further away from shore and
onto higher ground. While an agreement hasn’t been reached yet, the Boxing Day tragedy in Asia has reenergized
their efforts.
On April 1, 1946, a magnitude 7.4 earthquake occured off the southern coast of the Aleutian
Islands (just west of Alaska). Although the earthquake was relatively small, it lifted a huge part
of the sea bed and generated a massive tsunami. A 30m wave hit Scotch Gap on Unimak Island
within 45 minutes of the quake, completely destroying a 30m, reinforced concrete lighthouse
located well above sea level. Five hours later, the wave hit Hawaii killing 159 people. It was still
over 15m high when it ran aground in Hilo on the Big Island (shown above). This tsunami was
the impetus for what is now the Pacifi c Tsunami Warning System.

When a tsunami hits shallow water close to shore, it begins to
interact with the land. Part of the wave is refl ected back offshore,
like a ball hitting a wall. Turbulence and friction slow down the
part that is not refl ected, but because the wave has so much energy
to begin with none of these processes signifi cantly decrease its
overall energy.
When a tsunami slows down but doesn’t lose a lot of energy,
what do you think happens to the wave physically?
Tsunami 5
Physics tells us that when the energy in a system remains constant, but velocity decreases, the mass in the system
must increase. A slower moving tsunami, is a physically higher tsunami; all the water in the wave “scrunches together
like the ribs of an accordian and heaves upward” (Waves of destruction).
In other words, when the front part of the wave starts to slow down, all the mass at the back of the wave catches up
with it, and creates a MUCH bigger wave. As they reach land, very large tsunamis have been known to reach heights
of 30 meters. This measure is known as the run up height.
When a tsunami enters
shallow water it loses
velocity, but gains height.
Coming ashore
How a tsunami comes ashore really depends on how it begins and
how the land is shaped. In some cases, water will actually withdraw
from sheltered harbours, leaving boats stranded, shells exposed,
and fi sh gasping for breath on the exposed ground. In other cases,
the ocean just rises and rises without warning and a wall of water
fl oods onto shore.
The force with which the waves hit lands is tremendous. It is enough
to wipe away beaches, knock down trees and crush structures. The
water will continue inland for hundreds of meters, pushed along by
the huge mass of water behind it. To make matters worse, the wave
can be just as destructive as it withdraws, smashing together objects
caught in its wake, and dragging debris far out to sea.
In 1964, a magnitude 9.2 earthquake off the
coast of Alaska spawned a tsunami which
did extensive damage to many coastal
towns including Kodiak, AK (above) and
Port Alberni, BC.
Photo courtesy NOAA.
http://www.photolib.noaa.gov/historic/c&gs/theb1341.htm
Predicting tsunamis
Since most tsunamis are caused by earthquakes, being able to predict tsunamis means being able to predict earthquakes.
Unfortunately, predicting earthquakes is extremely diffi cult. As much as we do know about the Earth, there are too
many variables that contribute to earthquakes to know with any certainty when one will occur. The best scientists
can do is provide probabilities that tell us how often, on average, earthquakes of various sizes will occur.
For instance, the most geologically active region of Canada (and the continental United States) lies along the west
coast. In this region there are about 1000 small earthquakes each year, most so small that no one feels them. There
have been about 100 earthquakes of magnitude 5 or more in the last 70 years. Once every 10 years or so, there is an
earthquake of magnitude 7 or bigger – these are called crust damaging quakes. Big megathrust quakes (magnitude
9 or greater) occur only once every 300-500 years.
If we can’t know for sure when an earthquake and
tsunami will occur, how do probabilities help?

Tsunami formation is quite complex. The size and energy of the
wave are related to the earthquake’s magnitude and depth, water
depth where the quake occurs, the amount of vertical motion of the
sea fl oor, the velocity of that motion, and the effi ciency with which
energy is transferred from the earth’s crust to ocean water.
What is the diff erence between velocity and speed?
Do you know what engineers mean by effi ciency?
When an earthquake happens under water, the ocean fl oor can
drop (or rise) very suddenly. In a megathrust earthquake, the displacement
can be extremely large and occur over the entire length
(sometimes more than 1000km) and width of a fault. Energy is
transferred to the water both from the shaking of the earth and the
sudden rise or fall of the sea fl oor.
Why would a drop or rise in the sea fl oor
transfer energy to water?
The December 26, 2004 earthquake in the Indian Ocean dropped millions, possibly billions, of cubic meters of water
by about 15 m. In other words, in a very short period of time, the water went from having billions and billions of
joules of potential energy, to having billions and billions of joules of kinetic energy. This energy is what spreads out
from the source and across the ocean to form the tsunami wave.
What is the diff erence between potential and kinetic energy?
Even though tsunamis are big waves, in deep water their size is
hidden in the ocean depths. Crests may be a meter high or smaller
and separated by 100 kilometers or more, but they are also moving
extremely fast, sometimes more than 500 kilometers per hour. as
fast as a transcontinental airplane. Tsunamis don’t get large until
they get close to shore.

What happens to waves in a really strong wind or hurricane?
Every wave can be described by its amplitude, wavelength and period.
So, as devastating as tsunamis are for both people and property,
their formation and actions are governed by physics.
The amount of energy carried by a wave is related to its amplitude.
High energy waves have large amplitudes and low energy waves
have smaller amplitudes. In other words, bigger waves have way
more energy than smaller waves – and tsunamis are BIG waves.
The energy (E) in a wave is actually proportional (α) to the square
of its amplitude (A).
E α A2
This means that every time the amplitude of a wave doubles, the
energy it contains actually increases 4 times.
So while an every day 1m wave has 1 unit, a large tsunami of 32m
has over 1000 times more energy. The largest tsunamis are about
30 meters high when they hit land.

Amplitude, wavelength and period
To help measure the amount of energy in a wave, scientists make different measurements, which are shown in the
diagram. If you think of the diagram as a picture of waves on the water, the straight horizontal line represents the
water when it is perfectly still.
Peaks (or crests) are the highest points above the fl at water line.
Troughs are the lowest points below the fl at water line.
The amplitude of the wave is how high it is above the fl at water
line (or how low it is below the fl at water line).
The wavelength is the distance from peak to peak, or trough to
trough.
The period of the wave is the length of time from when one peak
passes a point to when another peak passes the same point.

Waves are a topic of particular interest in physics because many
natural phenomena – light, sound, and yes, water waves - occur
as waves.
Th ink about waves you seen on the water.
What do you know about waves?
In physics, a wave is a disturbance which moves through a medium
(water, air, a slinky) from one point to another. The key point is that
it is the disturbance that moves, not the medium. The disturbance
is caused by energy transferring from one particle to another, so
waves are sometimes called energy transfer phenomenon.
Have you ever been in a boat?
What happens to the boat when the water is wavy?
Waves of energy can pass back and forth
through the metal coils of a Slinky while
the Slinky as a whole never moves.
Tsunami 3
Amplitude and energy: Why size matters
What happens to waves in a really strong wind or hurricane?
Every wave can be described by its amplitude, wavelength and period.
So, as devastating as tsunamis are for both people and property,
their formation and actions are governed by physics.
The amount of energy carried by a wave is related to its amplitude.
High energy waves have large amplitudes and low energy waves
have smaller amplitudes. In other words, bigger waves have way
more energy than smaller waves – and tsunamis are BIG waves.
The energy (E) in a wave is actually proportional (α) to the square
of its amplitude (A).
E α A2
This means that every time the amplitude of a wave doubles, the
energy it contains actually increases 4 times.
So while an every day 1m wave has 1 unit, a large tsunami of 32m
has over 1000 times more energy. The largest tsunamis are about
30 meters high when they hit land.
Waves on water are usually caused by the wind. Individual molecules
of air traveling over the water’s surface crash into individual
molecules of water, and in doing so transfer energy to them. The
water particles then transfer energy to other nearby particles of
water and so on. We see this energy transfer as a ripple on the water,
or in heavier winds (which transfer more energy), waves. This
process keeps on going from one set of molecules to the next until
the waves reaches the shore.
All waves are energy transfer
phenomena.

Within hours killer waves radiating from the epicenter slammed into the coastline of 11 Indian Ocean countries, snatching people out to sea, drowning others in their homes or on beaches, and demolishing property from Africa to Thailand.

Tsunamis have been relatively rare in the Indian Ocean. They are most prevalent in the Pacific. But every ocean has generated the scourges. Many countries are at risk.

In the wake of the Christmas weekend tsunami in the Indian Ocean, one of the worst disasters in history, National Geographic News examines the killer waves' causes and warning signs—information that can be a lifesaver in a tsunami zone.

• A tsunami is a series of great sea waves caused by an underwater earthquake, landslide, or volcanic eruption. More rarely, a tsunami can be generated by a giant meteor impact with the ocean.

Scientists have found traces of an asteroid-collision event that they say would have created a giant tsunami that swept around the Earth several times, inundating everything except the mountains 3.5 billion years ago. The coastline of the continents was changed drastically and almost all life on land was exterminated.

Giant forces that had been building up deep in the Earth for hundreds of years were released suddenly on December 26, shaking the ground violently and unleashing a series of killer waves that sped across the Indian Ocean at the speed of a jet airliner.

By the end of the day more than 150,000 people were dead or missing and millions more were homeless in 11 countries, making it perhaps the most destructive tsunami in history.

The epicenter of the 9.0 magnitude quake was under the Indian Ocean near the west coast of the Indonesian island of Sumatra, according to the USGS, which monitors earthquakes worldwide. The violent movement of sections of the Earth's crust, known as tectonic plates, displaced an enormous amount of water, sending powerful shock waves in every direction.

The earthquake was the result of the sliding of the portion of the Earth's crust known as the India plate under the section called the Burma plate. The process has been going on for millennia, one plate pushing against the other until something has to give. The result on December 26 was a rupture the USGS estimates was more than 600 miles (1,000 kilometers) long, displacing the seafloor above the rupture by perhaps 10 yards (about 10 meters) horizontally and several yards vertically. That doesn't sound like much, but the trillions of tons of rock that were moved along hundreds of miles caused the planet to shudder with the largest magnitude earthquake in 40 years.

Above the disturbed seafloor the great volume of the ocean was displaced along the line of the rupture, creating one of nature's most deadly phenomena: a tsunami. Within hours killer waves radiating from the earthquake zone slammed into the coastline of 11 Indian Ocean countries, snatching people out to sea, drowning others in their homes or on beaches, and demolishing property from Africa to Thailand.