This ppt contais different systems by which we can detect the tusunami .And their advantages and disadvantages

1. TSUNAMI DETECTION SYSTEM
By
V.Srinithi (11321A05A4)
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2. Contents
 Tsunami
 Why Tsunami Detection System??
 Types of Tsunami Detection System
 Technologies Used
 Seismometers
 Coast Tidal Gauge
 DART Buoys
 Digiquartz Broadband Depth Sensor
 Acoustic Transducer
 Acoustic Link
 DART I & II System
 Advantages & Disadvantages
 Conclusion 2

3. Tsunami
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•Tsunami is a series of waves with extremely long wave length and long
wave period generated when a body of water rapidly displace.
•The causes of tsunami are:
Earthquakes
Land slides
Volcanic Erruptions
•It is one of the most powerful destructive forces of nature.
• Tsunami is originated from the japanese word ,which implies
“TSU” MEANS HARBOUR AND “NAMI” MEANS WAVE.
TSUNAMI = HARBOUR + WAVE.

4. Why Tsunami Detection System???
 A Tsunami Detection System is used to detect tsunamis as soon
as possible and issue warnings to coastal people so as to prevent
the loss of life and damage .
 It comprises of two equally significant components:
Network Of Sensors : To detect the tsunamis before sufficient
time .
Communication Infrastructure:It is used to bring out an
official document so that nearby coastal guards can give timely
alarms to permit evacuation of coastal areas.
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5. Types of Tsunami Detection System
There are two distinct types :
 International Warning System:
This system uses both data like seismic and water level data from
coastal buoys.
 National Warning System:
This system use seismic data about nearby recent earthquake.This
is classified as:
Tsunami Watches
Tsunami Warning
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6. Technologies Used
Three types of technologies are used for detecting tsunami:
 Seismometers
 Coast Tidal Gauges
 Dart Buoys
Dart I buoy
Dart II buoy
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7. Seismometer
 Earthquake are measured based on its magnitude recorded by its
seismograph.
 From the information available from seismograph we could find
about the source of tsunami .
Drawbacks :
 Data are indirect and interpretation is difficult.
 It involve poor understanding of seismic coupling
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8. Working of Seismometer
 Seismographs , generally consist of two parts, a
sensor of ground motion which we call
a seismometer, and a seismic recording
system.
 When a tsunami event occurs,
the first information available
about the source of the tsunami
is based only on the available
seismic information.
 Earthquakes are measured
based on its magnitude
recorded by a seismograph.
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9. Coast Tidal Gauge
 Measure sea level near coastal area and continuously monitors and
confirms tsunami waves following an earthquake.
Drawbacks :
 May not survive impact of tsunami.
 Cannot provide data that are especially important to operational
hazard assessment directly.
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10. Working of Coast Tidal Gauge
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11.  Modern tide gauges have two detection systems:
A primary system, based on different round-trip travel
times for sound waves projected down to sea level (high
or low tide) and reflected back, and
A second, back-up system, based on measuring pressure
differences as water height changes between the tides.
 Then the collected Sea level data is sent by satellites to a lab
somewhere else, like the Pacific Tsunami Warning Center .
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12. DART Buoys
 “DART” stands for Deep-ocean Assessment and Reporting of
Tsunamis.
 This is a system of buoys, located strategically around the
world’s oceans, which can alert scientists to the passage of a
tsunami.
 Here information is processed to produce a new and more
refined estimate of tsunami source and reported to tsunami
warning center.
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13. Modes of Operation
DART buoy has two modes of operation:
 Standard Mode:
Here Dart transmits data every six hours with recording
period of 15 minutes.
 Event Mode:
When tsunami wave occur standard mode trigger to event
mode. It transmit data every15 minutes at an average of 1 minute
for three hours.
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14. Working of DART Buoys
 DART Buoy consist of two main component:
Bottom Pressure Recorder (BPR)
Surface Buoy
 BPR consisting of a modem to transmit data to surface buoy.
 Surface buoy transmit data to warning centre via satellite
communication.
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15. Bottom Pressure Recorder :
 Digiquartz Broadband depth Sensor is the main sensing element.
 This sensor continuously monitors pressure and if pressure
exceeds threshold value, it automatically report to warning centre.
Surface Buoys:
 Surface buoys makes satellite communication to warning centers
that evaluate the threat and issue a tsunami warning.
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16. Digiquartz Broadband Depth Sensor
 This depth sensor provide accurate & stable data.
 Superior performance of digiquartz instruments is achieved through use
of quartz crystal.
 Pressure transducer employs bellows tube as pressure to load
generators.
 Change in frequency of quartz crystal oscillator is a measure of the
applied pressure.
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17. Acoustic Transducer
 A electrical device that converts sound wave into electrical
energy.
 Hydrophone is used in this case.
 When electrical plates are exposed to sound vibration electrical
energy is produced.
 Electrical energy is sent to amplifier and then to final destination.
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18. Acoustic Link
 Acoustic communication is a technique of sending and receiving
signals under water.
 It is done by help of acoustic modem.
 Modem operates at frequency of 10 Hz – 1 MHz.
 It provides an accurate and efficient method to send and receive
data underwater.
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19. DART I System
 Relied solely on software’s ability to detect a tsunami and trigger
to event mode and it provides only one way communication
ability.
 To avoid false alarm, a threshold value is set such that tsunami
with low amplitude could fail to trigger the station.
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20. Working of DART I System
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21. DART II System
 Measure seal level change of less than a millimeter in the deep
ocean.
 Two way communication allows for trouble shooting of the
system.
 System can be switched to event mode by concerned authority
for research purpose.
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22. Working of DART II System
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24. Advantages
 Deep water pressure produce low false reading.
 Multiple sensor can detect wave propagation.
 Good advance warning system.
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25. Disadvantages
 Expensive equipments.
 High maintenance cost.
 Require multiple communication link:
SONAR.
Satellite Uplink.
Satellite Downlink.
Notification to authorities.
Authorities notifies coastal dwellers.
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26. Conclusion
The Tsunami Detection System is quite useful in predicting the energy
level that obtained as result of natural disaster on ocean bed ,transfer to
ocean and its destructive potential ,which could alert people on the
arriving threat and saves from massive loss of mankind.
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27. References
[1] http://en.wikipedia.org/wiki/Tsunami_detection_system
[2]http://en.wikipedia.org/wiki/Deepocean_Assessment_and_Reporting_
of_Tsunamis
[3]http://seminarprojects.net/t-tsunami-detection-system
[4]http://www.authorstream.com/Presentation/aSGuest132268-1389817-
ppt-for-seminar-tsunami-alarm
[5]www.sonardyne.com
[6]www.collegelib.com
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28. THANK YOU
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