TSUNAMI DETECTION SYSTEM

By

V.Srinithi (11321A05A4)

1

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

Tsunami

3

•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.

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.

4

Types of Tsunami Detection SystemThere 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.Thisis classified as:

Tsunami Watches

Tsunami Warning

5

Technologies UsedThree types of technologies are used for detecting tsunami:

Seismometers

Coast Tidal Gauges

Dart Buoys

Dart I buoy

Dart II buoy

6

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

7

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.

8

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.

9

Working of Coast Tidal Gauge

10

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 .

11

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.

12

Modes of OperationDART 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.

13

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.

14

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.

15

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.

16

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.

17

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.

18

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.

19

Working of DART I System

20

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.

21

Working of DART II System

22

23

Advantages Deep water pressure produce low false reading.

Multiple sensor can detect wave propagation.

Good advance warning system.

24

Disadvantages Expensive equipments.

High maintenance cost.

Require multiple communication link:

SONAR.

Satellite Uplink.

Satellite Downlink.

Notification to authorities.

Authorities notifies coastal dwellers.

25

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.

26

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

27

THANK YOU

28