EARLY WARNING SYSTEM(EWS) By:::: Umang talpara

1. DISASTER
MANAGEMENT
EARLY WARNING SYSTEM
By::::
Umang talpara

2. CONTENTS
□ INTRODUCTION
□ EARTHQUAKE WARNING
SYSTEM
□ FLOOD WARNING SYSTEM
□ TSUNAMI WARNING SYSTEM

3. INTRODUCTION
□ An Early Warning System (EWS) can be defined as a set of
capacities needed to generate and disseminate timely and
meaningful warning information of the possible extreme events or
disasters (e.g. floods, drought, fire, earthquake and tsunamis) that
threatens people’s lives.
□ The purpose of this information is to enable individuals,
communities and organizations threatened to prepare and act
appropriately and in sufficient time to reduce the possibility of harm,
loss or risk.

4. □ An early warning system can be implemented as a chain of
information communication systems and comprises sensors,
event detection and decision subsystems. They work together
to forecast and signal disturbances that adversely affect the
stability of the physical world, providing time for the response
system to prepare for the adverse event and to minimize its
impact.
□ To be effective, early warning systems need to actively
involve the communities at risk, facilitate public education and
awareness of risks, effectively disseminate alerts, and
warnings and ensure there is constant state of preparedness.
A complete and effective early warning system supports four
main functions: risk analysis, monitoring and warning;
dissemination and communication; and a response capability.

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6. EARTHQUAKE WARNING
SYSTEM
- Earthquake early warning systems use earthquake science and the
technology of monitoring systems to alert devices and people when
shaking waves generated by an earthquake are expected to arrive at
their location.
- This can be done by detecting the first energy to radiate from an
earthquake, the P-wave energy, which rarely causes damage. Using P-
wave information, we first estimate the location and the magnitude of
the earthquake. Then, the anticipated ground shaking across the region
to be affected is estimated and a warning is provided to local
populations. The method can provide warning before the S-wave

7. arrives, bringing the strong shaking that usually causes most of the
damage.

8. - A user receives a message like this on the screen of his
computer. The message alerts the user to how many seconds
before the shaking waves arrive at their location and the
expected intensity of shaking at that site.
- The warning message also displays a map with the location
of the epicenter, the magnitude of the quake, and the current
position of the P and S waves.

9. Epicenter#
Sensors
Earthquake
alert center
Sensors positioned
about 6* 12 miles apart
xS-wave Is P-wave

10. Flood Warning System
- The development of flood forecasting and warning systems is an essential element in
regional and national flood preparedness strategies, and is a high priority in many countries.
Flood EWS are being considered as an alternative for dealing with flood problems, partly
because these systems are less expensive compared to structural schemes.
- The benefits of flood early warning systems come from the savings in flood damages. Floods
are random events that cause damages and hence flood damages are also random or
probabilistic events: the probability of any specific amount of flood damage depends on the
probability of the flood event necessary to cause those damages. Determining flood
damages combines a risk assessment in terms of the probability of future flood events to be
averted, and a vulnerability assessment in terms of the damage that would be caused by
those floods and, therefore, the economic savings to be gained by their reduction.

11. Components involved
- The wireless system manages flood or flash flood risk by providing
early warnings to downstream communities and enhances
cooperation between upstream and downstream communities in the
sharing of flood information.
- This solution consists of two units Transmitter Receiver
- The transmitter is installed along the riverbank, and the receiver is
installed at a house near the river.

12. - A flood sensor attached to the transmitter detects rising water levels.
When the water reaches a critical level, a signal is wirelessly
transmitted to the receiver.
- The flood warning is then disseminated via mobile phone to
concerned agencies and vulnerable communities downstream.
Critical flood levels are set with the help of the local community.

13. Thresholds
vhen to issue
Detection
(meteorological
monitoring)
Forecasting
(meteorological
modelling)
a warning)
Warning dissemination Preparedness
(issue warnings to the (emergency planning public
affected population) awareness, etc.)
Response
(Contingency
plans)
Recover/
(Repair and clean-up
operations, care for victims)
Review
(Can the system
be improved?)

14. TRANSMITTER & RECEIVER
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Level
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Wireless FEWS Technology showing Upstream Transmitter
and Downstream Receiver

15. FLOODS OF VADODARA

16. Tsunami Warning System
(TWS)
- A tsunami warning system (TWS) is used to detect tsunamis in advance
and issue warnings to prevent loss of life and damage to property. It is
made up of two equally important components: a network of sensors to
detect tsunamis and a communications infrastructure to issue timely
alarms to permit evacuation of the coastal areas.
- There are two distinct types of tsunami warning systems: international
and regional. When operating, seismic alerts are used to instigate the
watches and warnings; then, data from observed sea level height (either
shore-based tide gauges or DART buoys) are used to verify the existence
of a tsunami. Other systems have been proposed to augment the
warning procedures

17. Types of detectors normally used
1. TIDAL GAUGE
- A sensor network is used to record measurements of changes in sea
levels. A general working principle involves water travelling through a
bottom pipe hooked to electronic sensors that are designed to measure
the height of this water passing through.
- A GPS system is also used for measuring tidal water levels. Water
enters the tide gauge through a bottom pipe, and the water level is
measured using electronic sensors, usually GPS. The device consists of
two antennas and receivers, one pointing to zenith and the other pointed
down towards the sea surface. The former antenna tracks the direct
signal, and the latter traps the reflected signal from the water surface.
The interference between the direct and reflected signals can be
determined by the signal-to-noise ratio data.

18. 2. Deep-ocean Assessment and Reporting of Tsunamis (DART)
- Deep-ocean Assessment and Reporting of Tsunamis (DART) is a
component of an enhanced tsunami warning system. By logging
changes in seafloor temperature and pressure, and transmitting
the data via a surface buoy to a ground station by satellite,
DART enables instant, accurate tsunami forecasts. In Standard
Mode, the system logs the data at 15-minute intervals, and in
Event Mode, every 15 seconds. A 2-way communication system
allows the ground station to switch DART into Event Mode
whenever detailed reports are needed.

19. COAST TIDAL GAUGE DART BUOYS
Tsunami warning system
Data relayed to satellite.
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Acoustic link transmits
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20. CONCLUSION
- So hereby we conclude that by using Early Warning
System (EWS) timely and meaningful warning
information of the possible extreme events or
disasters (e.g. floods, drought, fire, earthquake and
tsunamis) that threatens people’s lives and cause
damage to infrastructure can be reduced to certain
levels.