tsunami warning system (synofsis)

Tsunami Warning System

1. INTRODUCTION

The word tsunami is derived from Japanese, denoting port or harbor (tsu) and sea wave

(nami) caused by seismic activity. Tsunami is a wave in the ocean or in a lake that is

created by geologic event characterized by a series of waves with extremely long wave

length and long wave period. These gigantic waves are probably one of the most

powerful and destructive forces of nature. Tsunami may occur by earthquakes, submarine

Landslides, Volcanic eruption and meteorites striking the earth. Cases include geological

factors such as the landslide happen underwater plate earthquake and coastal areas as the

cause of the tsunami in the sea and submarine volcanic activity, submarine landslide was

caused by falling meteorites into oceanic later in the past have been confirmed. Usually

due to undersea tectonic dislocations, such as in geological faults along the deep ocean

trenches providing its energy, a tsunami can travel hundreds of miles over the open sea

and cause extensive damage when it encounters land and also called as tidal waves,

where it impacts with varying degrees of severity.

Since earthquakes cannot be predicted, Tsunami also cannot be predicted. But we can

forecast tsunami arrival times and wave heights through the use of computer modeling

after a tsunamigenic earthquake has been recorded.

After grasping the fundamentals, more realistic conditions for models of the ocean-earth

conditions are considered. These are treated by numerical methods finite-difference or

finite-element.

A tsunami warning system (TWS) is used to detect tsunamis in advance and issue

warnings to prevent loss of life and damage. Tsunami Warning System are much more

complicated even then tsunamis themselves, because people and instruments are also involved.

Totally six Tsunami Warning System exists worldwide: French, Russian, Japanese, Hawaiian,

Aleutian and Pacific. The system as a whole from detecting the seismic event to disseminating

warnings to activating sirens or other local notification devices is designed to work efficiently

and quickly to ultimately help save lives. The Tsunami Early Warning System comprises a

real-time network of seismic stations, Bottom Pressure Recorders (BPR), tide gauges and

24 X 7 operational warning centre to detect tsunamigenic earthquakes, to monitor

1 | P a g eM.Sc I yr (Computer Science) Semester I


tsunamis and to provide timely advisories following the Standard Operating Procedure

(SOP), to vulnerable community by means of latest communication methods with back-

end support of a pre-run model scenario database and Decision Support System (DSS).

The Warning Centre is capable of issuing Tsunami bulletins in less than 10 minutes after

any major earthquake in the Ocean thus leaving us with a response/lead time of about 10

to 20 minutes for near source regions and a few hours in the case of mainland.

The Tsunami Early Warning System (TWS) consists of two equally important

components i.e. networks of sensors to detect tsunamis and communication infrastructure

to issue timely alarms to permit evacuation of coastal areas.

Network of seismic monitoring station at sea floor detects presence of earthquake.

Seismic monitoring station determines location and depth of earthquake having potential

to cause tsunami. Any resulting tsunami are verified by sea level monitoring station such

as DART buoys, tidal gauge. Communication infrastructure to issue timely alarms to

permit evacuation of coastal areas.


TWSNetwork of sensorsCommunication Infrastructure


There are two distinct types of Tsunami Warning System (TWS) presently exist in the

world. They are “International Warning System” and “National Warning System”.

International Warning System - uses both data like seismic and water level data from

coastal buoys. Tsunami travel at 500-1000 km/hr, while seismic wave travel at 14,400

km/hr. This give sufficient time for tsunami forecast to be made. It is commonly used in

Pacific Ocean and Indian Ocean

National Warning System - use seismic data about nearby recent earthquakes to

determine if there is a possible local threat of a tsunami. Such systems are capable of

issuing warnings to the general public (via public address systems and sirens) in less than

15 minutes. Although the epicenter and moment magnitude of an underwater quake and

the probable tsunami arrival times can be quickly calculated.

It is almost always impossible to know whether underwater ground shifts have occurred

which will result in tsunami waves. As a result, false alarms can occur with these

systems, but the disruption is small, which makes sense due to the highly localized nature

of these extremely quick warnings, in combination with how difficult it would be for a

false alarm to affect more than a small area of the system. Real tsunamis would affect

more than just a small portion


Tsunami Warning SystemInternational Warning SystemNational Warning System

https://en.wikipedia.org/wiki/Moment_magnitude_scale

https://en.wikipedia.org/wiki/Epicenter

https://en.wikipedia.org/wiki/Seismic


There are two distinct types of National Warning System (NWS) exist. They are

“Tsunami Watches” and “Tsunami Warning”.

Tsunami Watches - a Tsunami Watch is automatically declared by the Tsunami

Warning Center (TWC) for any earthquake magnitude 7.5 or larger (7.0 or larger in the

Aleutian Islands) if the epicenter is in an area capable of generating a tsunami. Civil

Defense is notified, and the local media is provided with public announcements. TWC

then waits for data from tide gauge stations to confirm whether or not a tsunami has been

generated.

TWC also requests reports on wave activity from tide-gauge stations near the earthquake

epicenter. If the stations observe no tsunami activity, the Tsunami Watch is canceled. If

the stations report that a tsunami has been generated, a Tsunami Warning is issued. A

warning may be issued automatically if an earthquake powerful enough to create a

tsunami occurs nearby. The emergency broadcast system alerts the public of the danger,

and evacuation begins. Remember, tsunamis travel at 500 miles per hour; as soon as a

warning has been issued you should evacuate immediately.

Tsunami Warning - the objective of the Tsunami Warning System TWS is to detect,

locate, and determine the magnitude of potentially tsunamigenic earthquakes occurring in

the Ocean Basin or its immediate margins. Earthquake information is provided by various

seismic stations, National Earthquake Information Centre and international sources. If the

location and magnitude of an earthquake meet the known criteria for generation of a

tsunami, a tsunami warning is issued to warn of an imminent tsunami hazard. The

warning includes predicted tsunami arrival times at selected coastal communities within


National Warning SystemTsunami WatchesTsunami Warning

http://wwwneic.cr.usgs.gov/


the geographic area defined by the maximum distance the tsunami could travel in a few

hours.

If a significant tsunami is detected by sea-level monitoring instrumentation, the tsunami

warning is extended to the Ocean Basin. Sea-level (or tidal) information is provided by

NOAA's National Ocean Service, National Earthquake Information Centre, university

monitoring networks and other participating nations of the TWS. The International

Tsunami Information Centre, part of the Intergovernmental Oceanographic Commission,

monitors and evaluates the performance and effectiveness of the Tsunami Warning

System. This effort encourages the most effective data collection, data analysis, tsunami

impact assessment and warning dissemination to all TWS participants.


http://earthweb.ess.washington.edu/tsunami/general/warning/itic.html

http://earthweb.ess.washington.edu/tsunami/general/warning/itic.html

http://wwwneic.cr.usgs.gov/

http://www.nos.noaa.gov/welcome.html


2. OBJECTIVE

1. To detect tsunamis in advance and issue warnings to prevent loss of life and

property.

2. To help warn people about impending tsunami threats based on analysis of the

seismic event, or earthquake, and other data and models.

3. FEATURES

Features of tsunami are as follows:

All types of waves, including tsunami, have a wavelength, a wave height, amplitude, a

frequency or period, and a velocity. The physical characteristic of Tsunami is shown in

figure.

1. Wavelength: The distance between two identical points on a wave (i.e. between

wave crests or wave troughs) is called as wavelength. Normal ocean waves have

wavelengths of about 100 meters. Tsunami is usually having the longer wavelengths and

up to 500 kilometers.

2. Wave height: The distance between the trough of the wave and the crest or peak

of the wave is usually referred as wave height.



3. Wave amplitude: The height of the wave above the still water line, usually this is

equals to 1/2 the wave height. Tsunami can have variable wave height and amplitude that

depends on water depth as we shall see in a moment.

4. Wave frequency: The amount of time it takes for one full wavelength to pass a

stationary point is called as wave frequency or wave period.

5. Wave velocity is the speed of the wave. Velocities of normal ocean waves are

about 90km/hr while tsunami have velocities up to 950 km/hr (about as fast as jet

airplanes), and thus move much more rapidly across ocean basins. The velocity of any

wave is equal to the wavelength divided by the wave period. V = λ/P

Features of Tsunami Warning System (TWS) are as follows:

1. Locate and characterize the earthquake’s source and its probability of creating a

tsunami via the collection of data from seismic networks.

2. Review automated earthquake analysis, and if necessary, modifies (by the duty

scientist or watch stander) the automated results.

3. Obtain continuous sea level data from tide gage sites, and where available, data

from Deep Ocean Assessment and Reporting of Tsunamis DART buoys, to verify the

existence of a tsunami and to calibrate models.

4. Prepare and disseminate information to appropriate emergency management

officials and others.



4. WORKING

There are three ways for detecting the Tsunami.

1. Seismometers.

2. Coast Tidal Gauges.

3. DART Buoys .

1. A seismograph, or seismometer, is an instrument used to detect and record

seismic waves. Seismic waves are propagating vibrations that carry energy from the

source of an earthquake outward in all directions. They travel through the interior of the

Earth and can be measured with sensitive detectors called seismographs. Scientists have

seismographs set up all over the world to track the movement of the Earth’s crust.

Seismic waves are divided into two types: Body Waves and Surface Waves.

Body waves include P (compressional or primary) waves and S (transverse or secondary)

waves. An earthquake radiates P and S waves in all directions and the interaction of the P

and S waves with the Earth's surface and shallow structure produces.

Surface waves. Near an earthquake, the shaking is large and dominated by shear-waves

and short-period surface waves. These are the waves that do the most damage to our

buildings, highways, etc.

At farther distances the amplitude of the seismic wave’s decreases as the energy released

by the earthquake spreads throughout a larger volume of Earth. Also with increasing 8 | P a g e

M.Sc I yr (Computer Science) Semester I

Detecting the Tsunami SeismometersCoastal tidal guageDART buoys


distance from the earthquake, the waves are separated apart in time and dispersed because

P, S, and surface waves travel at different speeds.

Love waves and Rayleigh waves are surface waves.

Love waves are transverse waves that vibrate the ground in the horizontal direction

perpendicular to the direction that the waves are travelling. They are recorded on

seismometers that measure the horizontal ground motion.

Rayleigh waves are the slowest of all the seismic wave types and in some ways the most

complicated. Like Love waves they are dispersive so the particular speed at which they

travel depends on the wave period and the near-surface geologic structure, and they also

decrease in amplitude with depth. Typical speeds for Rayleigh waves are on the order of

1 to 5 km/s.

Generally, a seismograph consists of a mass attached to a fixed base. During an

earthquake, the base moves and the mass do not. The motion of the base with respect to

the mass is commonly transformed into an electrical voltage. The electrical voltage is

recorded on paper, magnetic tape, or another recording medium. The record written by a



seismograph in response to ground motions produced by an earthquake or other ground-

motion sources is called seismogram.

Seismographs record a zig-zag trace that shows the varying amplitude of ground

oscillations beneath the instrument. This record is proportional to the motion of the

seismometer mass relative to the earth, but it can be mathematically converted to a record

of the absolute motion of the ground.

Information available about source of tsunami is based on seismic information.

Earthquake are measured based on its magnitude recorded by its seismograph.

When a tsunami event occurs, the first information available about the source of the

tsunami is based only on the available seismic information. Earthquake are measured

based on its magnitude recorded by a seismograph.

2. Coastal Tidal gauge

Tide gauge is a device for measuring sea level and detecting tsunami. Tide gauges that

are close to the earthquake would be able to detect the rise in the sea level that a tsunami

would produce.

There are fundamentally four types of sea level measuring technology in common use:

1. Stilling well and float: in which the filtering of the waves is done through the

mechanical design of the well.

2. Pressure systems: in which sub-surface pressure is monitored and converted to

height based on knowledge of the water density and local acceleration due to gravity.

Such systems have additional specific application to ocean circulation studies in which

pressure differences are more relevant than height differences.

3. Acoustic systems: in which the transit time of a sonic pulse is used to compute

distance to the sea surface.

4. Radar systems: similar to acoustic transmission, but using radar frequencies.



Importance:

In order to confirm the tsunami waves following an earthquake, to monitor the progress

of tsunami and later for cancellation of warning, it is essential to monitor the coastal sea

level changes. A network of tide gauges may be the only way of detecting a Tsunami in

cases where seismic data is not available or when the Tsunami is triggered by events

other than an earthquake.

Each field station is equipped with two types of sensors in the tide gauge system:

Pressure sensors and acoustic sensors, to measure tide levels.

The pressure sensors can be fixed directly in the sea to monitor sub-surface pressure.

The sensor is connected by a cable that carries power and signal lines to an onshore

control and logging unit. The sensor is usually contained within a copper or titanium

housing with the cable entering through a watertight gland. Material used for the housing

is chosen to limit marine growth.



The acoustic tide gauges depend on measuring the travel time of acoustic pulses

reflected vertically from the sea surface. This measurement is made with the acoustic

transducer mounted vertically above the sea surface, located inside a tube that provides

some degree of surface stilling and protects the equipment.

Each tide gauge measures the sea level by sampling for every one minute and transmits it

for every 5 minutes. The filed stations are equipped with necessary power and

communication facilities. The real time data from field stations is transmitted

simultaneously to the central receiving stations.

3. DART (Deep Ocean Assessment & Reporting Of Tsunami)

Each DART station consists of a surface buoy and a seafloor bottom pressure

recording (BPR) package that detects pressure changes caused by tsunamis. The surface

buoy receives transmitted information from the BPR via an acoustic link and then

transmits data to a satellite, which retransmits the data to ground stations for immediate

dissemination to NOAA's Tsunami Warning Centers, NOAA's National Data Buoy

Center, and NOAA's Pacific Marine Environmental Laboratory (PMEL).

When on-board software identifies a possible tsunami, the station leaves standard mode

and begins transmitting in event mode. In standard mode, the station reports water

temperature and pressure (which are converted to sea-surface height) every 15

minutes. At the start of event mode, the buoy reports measurements every 15 seconds for

several minutes, followed by 1-minute averages for 4 hours.

There are two types of DART system:

The first-generation DART I stations had one-way communication ability, and relied

solely on the software's ability to detect a tsunami to trigger event mode and rapid data

transmission. In order to avoid false positives, the detection threshold was set relatively

high, presenting the possibility that a tsunami with low amplitude could fail to trigger the

station.

The second-generation DART II is equipped for two-way communication, allowing

tsunami forecasters to place the station in event mode in anticipation of a tsunami's

arrival.


https://en.wikipedia.org/wiki/Pacific_Marine_Environmental_Laboratory

https://en.wikipedia.org/wiki/Tsunamis

https://en.wikipedia.org/wiki/Pressure

https://en.wikipedia.org/wiki/Seafloor

https://en.wikipedia.org/wiki/Buoy


Hardware Description

Microcontroller

In this work, the pressure is induced using piston pump. The pressure is sensed using

capacitive proximity sensor and the raise in the pressure which is above the threshold

value is send as signal to the transmitter side microcontroller. Microcontroller used in this

work is AT89C2051. It is a 20 pin DIP. The AT89C2051 is a low voltage, high

performance CMOS 8-bit microcomputer with 2K bytes flash programmable and erasable

read only memory (PEROM). By combining a versatile 8-bit CPU with flash on a

monolithic chip, the Atmel AT89C2051 is a powerful microcomputer which provides a

highly flexible and cost-effective solution to many embedded control applications. The

AT89C2051 provides the following standard features: 2K bytes of flash, 18 bytes of

RAM, 15 I/O lines, two 16 bit timer/counters, and five vector low levels interrupt

architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator

and clock circuitry. In addition, the AT89C2051 is designed with static logic for

operation down to zero frequency and supports two software selectable power saving

modes. The idle mode stops the CPU while allowing the RAM, timer/counters, serial port

and interrupt system to continue functioning. The power down mode saves the RAM

content but disables all other chip functions until the next hardware reset.

Transmitter

The light source LED produces a light beam across the bottom of the coil. IR (infrared)

rays are chosen because there is less noise and ambient light than at normal optical

wavelengths. LED is used as transmitter and it uses Infrared rays to transmit the signals.

The transmitter module diagram



Fig: Transmitter Module Diagram Fig: Receiver Module Diagram

In the transmitter module, the capacitive sensor senses the change in capacitance. If the

actual value exceeds the target value then it considers that there is some abnormal

condition. The value is given as interrupt signal on the port P3.2 of AT89C2051

microcontroller. As a result, the data signal and carrier signal are generated by the

microcontroller. Data signal is pulse code modulated with the carrier wave. Negative

pulse code modulation is performed. The signal is passed to receiver in the form of IR

rays with the help of LED.

Receiver

TSOP 1738 is the receiver used in this study which has the capability to receive

frequency with the range of 38 kHz. TSOP 1738 is the standard IR remote control

receiver series, supporting all major transmission codes. The receiver module diagram is

shown in figure 5. In the receiver module, TSOP1738 receives the signal in the input pin.

This is given as input to another AT89C2051 microcontroller on the interrupt pin P3.2.

The PC is interfaced with the microcontroller through MAX-232 level converter, in order

to convert TTL logic to RS logic. In MAX-232 11th pin takes the microcontroller TTL

logic and process it and then gives the RS logic output on the 14th pin. The buzzer is

interfaced with the microcontroller on the port P1.5.

Capacitive Sensor

Proximity capacitive sensor is used in this study. This sensor contains a dielectric

material separated by an electric plate and comparator. When there is any variation in



capacitance value, the comparator compares the actual value with the target value. Based

on this principle, capacitive sensor gets operated.

MAX-232 Level Converter

The MAX-232 level converter is a 16 pin DIP. It contains dual charge pump DC-DC

voltage converters, RS 232 drivers, RS 232 receivers and receiver and transmitter enable

control inputs.

RS232

RS232 devices can be plugged straight into the computers serial port. This is referred to

as COM port. The data acquisition device used here is capacitive sensors. Its output is fed

through microcontroller. In warning phase mobile is connected to PC through the RS232

port.

Software Description

Keilμvision2

This is used to compile the code written for the microcontroller. The microcontroller code

is written using embedded C. It encapsulates the following components:

• A project manager.

• A make facility.

• Tool configuration.

• Editor.

• A powerful debugger.

Project Manager

A project is composed of all source files, development, tool options and directions

necessary to create a program. A single μVISION2 project can generate one or more

target programs. The source files used to create a target are organized into groups. The

development tools can be set at target, group, or file level.

Integrated Utilities

The tools menu is used to start the user utilities within the μVISION2 IDE. A

configurable interface provides access to version control systems.

Editor



The μVISION2 editor includes all the editing features, color syntax, highlighting and text

indentation for the C source code. The editor is available while debugging the program

and this gives a natural debugging environment that lets to quickly test the application.

Debugger

The debugging is performed through breakpoints. Its sets program breakpoints while

editing. Breakpoints are activated while starting the debugger. It may be set on

conditional expressions, International Journal of Embedded Systems and Applications

(IJESA) Vol.1, No.2, December 2011 72 or variable and memory access. Debug

functions can be executed when the breakpoints are triggered.

PROGRAMING MICROCONTROLLER IN KEIL

The complex problems faced by the embedded software developers are solved by the keil

developing tools.

When starting a new project, microcontroller to be used from the device database

should be selected and the μVISION IDE sets all compiler, assembler, linker and memory

options.

The keil μVISION debugger accurately simulates on chip peripherals.

To test the software with target hardware some adapter are used to download and

test program code on the target system.

Cross Assembling

On writing programs for microcontrollers, cross assembler or cross compilers are used. A

cross assembler is an assembler that runs on the host system, but produces binary

instructions which is suitable for the target system. And a cross compiler works similar to

the cross assembler.

VB .NET

VB.NET is the most productive tool for creating .NET applications. It provides the

following features:

• Common Language Runtime.

• Language Interoperability.

• Enhanced security.

• Simplified deployment.



• Improved versioning support.

The controls used in this project include,

1. Microsoft Communication Control

2. Oxygen Mobile SMS Control

Microsoft Communication Control

The Microsoft communication control provides serial communications for the application

by allowing the transmission and reception of data through a serial port. The Microsoft

communication control provides the following two ways for handling communications:

Event Driven

Event driven communication is a very powerful method for handling serial port

interaction. When a character arrives or a change occurs in the Carrier Detect (CD) or

Request to Send (RTS) lines then they are notified immediately. In such cases, the

Microsoft communication International Journal of Embedded Systems and Applications

(IJESA) Vol.1, control’s On Communication events are used to trap and handle these

communication events. The On Communication event also detects and handles

communications errors.

Polling for Events

Polling for events and errors are done by checking the value of the COM Event property

after each critical function of the program. This may be preferable if the application is

small and self-contained.

Oxygen Mobile SMS ActiveX control

This project uses the oxygen mobile SMS control OCX to send SMS to the destination

user via Simple Message Service. Oxygen Mobile ActiveX Control is designed to give an

access to various Nokia phone capabilities from a Windows program. Oxygen Mobile

ActiveX Control has modules messaging and are independent to each other and can be

used together or separately from each other. Each module or their combination has

methods for establishing phone connection and retrieving basic phone parameters like

model internal name, software and hardware versions, and signal and battery levels of the

phone. To work with Oxygen Mobile ActiveX Control Com Number should be set and

Connection Mode properties, call Open method should also be specified. When



connection is established phone is ready to work. To close connection to the phone, call

Close method must be used. The following flowcharts illustrate the Tsunami warning

system.

Transmitter Side Flow during Detection Receiver Side Flow during Detection

Fig: basic steps followed during initiation Fig: Update Settings “command button



Fig: operations performed during form load

The microcontroller is programmed with embedded C language, compiled using keil

compiler and the verified program was fused into microcontroller using the

microcontroller burner. Then the pressure variations are sensed using capacitive

proximity sensor and then providing warnings using mobile by means of oxygen Mobile

SMS Control. Based on the pressure changes under the sea, Tsunami could be detected in

advance

5. ADVANTAGES

Deep water pressure produce low false reading

Multiple sensors can detect wave propagation.

Good advance warning system.

DISADVANTAGE

Expensive equipments.

High maintenance cost.

Require multiple communication links: SONAR. Satellite Uplink.

Satellite Downlink. Notification to authorities. Authorities notify coastal

dwellers.



6. CONCLUSION

The phenomena of tsunamis, their origin, generation, travel, and terminal effects have

been described. As these life-threatening oceanic processes are being better understood,

so precautionary methods and warning systems are being developed. There still remains a

great deal of uncertainty as to whether any major tsunami would result from a large

earthquake near the coast. The possible arrival time at distant locations can readily be

predicted, whereas the degree of danger it might present would not be predictable with

certainty.

In efforts to provide timely warnings, quite often the very effects warned against might

not happen at all. This, coupled with the unpredictability of major earthquakes, has led

the public to distrust and even be callous toward tsunami-warning systems. Nevertheless,

these phenomena do occur, creating intensive widespread damage, and inhabitants of

exposed coastal regions can never be totally immune to tsunami attack. For this reason,

time and money devoted to developing and maintaining global tsunami-warning systems

are to be considered well spent.

7. FUTURE SCOPE

In future Tsunami occurrence can be decided and alarm can be raised only after checking

many criteria. Four criteria to be checked out are as follows:

• Pressure inside the sea bed.

• Tide level.

• Biological changes in the marine living organisms.

• Sea shore level.

If all these four criteria get detected then it can be concluded that there is some

occurrence of natural disaster (Tsunami).



8. REFERANCE

http://en.wikipedia.org/wiki/Tsunami_warning_system

http://seminarprojects.net/t-tsunami-warning-system

http://www.authorstream.com/Presentation/aSGuest132268-1389817-ppt-for-seminar-

tsunami-alarm

http://www.tsunamiterror.info/future_proposed.html

http://geography.about.com/od/physicalgeography/a/tsunami_2.html

https://en.wikipedia.org/wiki/Seismometer

http://www.hilo.hawaii.edu/~nat_haz/tsunamis/watchvwarning.php

http://www.sms-tsunami-warning.com/pages/seismograph#.VeNe4iWqqkq

https://en.wikipedia.org/wiki/Tide_gauge

https://en.wikipedia.org/wiki/Deep-ocean_Assessment_and_Reporting_of_Tsunamis

http://earthweb.ess.washington.edu/tsunami/general/warning/warning.html

http://www.slideshare.net/2507052220/tsunami-warning-system-31764975?

qid=59f7a842-665f-4d79-8cb2-56fd8f84b1bb&v=qf1&b=&from_search=1

http://www.slideshare.net/sasidevi984/tsunami-warning-system-46599481?qid=f17cefab-

e63a-433d-a1a4-1fcbed0b4bd0&v=default&b=&from_search=9

http://airccse.org/journal/ijesa/papers/1211ijesa06.pdf

a


http://www.slideshare.net/sasidevi984/tsunami-warning-system-46599481?qid=f17cefab-e63a-433d-a1a4-1fcbed0b4bd0&v=default&b=&from_search=9

http://www.slideshare.net/sasidevi984/tsunami-warning-system-46599481?qid=f17cefab-e63a-433d-a1a4-1fcbed0b4bd0&v=default&b=&from_search=9

http://www.slideshare.net/2507052220/tsunami-warning-system-31764975?qid=59f7a842-665f-4d79-8cb2-56fd8f84b1bb&v=qf1&b=&from_search=1

http://www.slideshare.net/2507052220/tsunami-warning-system-31764975?qid=59f7a842-665f-4d79-8cb2-56fd8f84b1bb&v=qf1&b=&from_search=1

http://earthweb.ess.washington.edu/tsunami/general/warning/warning.html

https://en.wikipedia.org/wiki/Deep-ocean_Assessment_and_Reporting_of_Tsunamis

https://en.wikipedia.org/wiki/Tide_gauge

http://www.sms-tsunami-warning.com/pages/seismograph#.VeNe4iWqqkq

http://www.hilo.hawaii.edu/~nat_haz/tsunamis/watchvwarning.php

https://en.wikipedia.org/wiki/Seismometer

http://geography.about.com/od/physicalgeography/a/tsunami_2.html

http://www.tsunamiterror.info/future_proposed.html

Technology

tsunami warning system (synofsis)