SUBMITTED TO:

AR. KAJAL HANDA ARSHI

SUBMITTED BY:

BHANU KHANNA (21008)

PANKHURI MITTAL (21019)

RAHUL PURI (21021)

B.ARCH 10TH SEM

What is tsunami? A tsunami is a large wave, or series of waves usually

Caused by:

An earthquake

Volcanic eruptions

Underwater explosions or landslides

Meteorite impact

Large earthquakes that cause uplift or

subsidence of sea floor

Underwater landslides

Volcano flank collapse

Physical characteristics of tsunami:

Wavelength

Normal ocean waves have wavelengths =100 m

Tsunami waves have wavelengths= up to 500

kms.

Wave velocity is the speed of the wave. Velocities of normal ocean waves are about 90 km/hr while tsunami

have velocities up to 950 km/hr

Wave height -distance between the trough and the crest of the wave

Wave amplitude - refers to the height of the wave above the still water line.

How do tsunamis differ from normal water waves?

Wind-generated waves usually have a period of 5 to 20 sec. And a wavelength of 100 to 200 meters.

Tsunami are characterized as shallow-water waves.

A tsunami can have a period in the range of 10 min. To 2hrs and wavelengths > 500 km.

Wave Refraction is

caused by segments

of wave moving at

different speeds

Earthquake causes tsunami: The most common causes of tsunamis are underwater

earthquakes.

Tectonic plates are constantly in motion, moving

along each other at a speed

of 1 to 2 inches/year.

The movement occurs along fault lines.

These motions are capable of producing earthquakes and

volcanism, which, when they

occur at the bottom of the

ocean, are two possible

sources of tsunamis

Major tectonic plates on the

earths surface

A geological theory proposes that earth's lithosphere is broken up into seven major and many minor plates, called tectonic plates.

Tectonic plates or lithosphere plates are large, irregularly shaped

slabs of solid rock, consisting of oceanic and continental

lithosphere.

Earthquake causes tsunami:

Earthquake causes

tsunami:

Earthquake causes tsunami:

Volcanic eruptions causes tsunami: A submarine or offshore

volcanic

eruption can

produce high

magnitude lifts

on seafloors,

which pushes

large water

columns

upwards to

generate

tsunami.

Submarine volcanoes can be detected by the presence of high rock content and steam above

water surface.

Landslides causes Tsunami Landslides moving into oceans,

bays, or lakes can also generate

tsunami.

Most such landslides are generated by earthquakes or volcanic

eruptions.

As previously mentioned, a large landslide or debris avalanche fell

into lituya bay, alaska in 1958

causing a wave with a run-up of

about 60 m as measured by a zone

completely stripped of vegetation.

Where and how frequently are tsunamis generated? The pacific ocean

occupies more

than one third of

the earth's

surface and is

bounded by areas

called the ring of fire, which includes

mountain chains,

underwater

trenches, and

islands.

in the average, there are two

tsunamis per year in the pacific

ocean somewhere, which cause

damage near the source.

Approximately every 15 years a destructive tsunami occurs

in pacific.

The destructive tsunami on dec 26th, 2004 on the indian

coast interms of its impact

seems to have occurred for

the first time in the history.

Where and how frequently are tsunamis generated?

Indian Ocean Tsunami of Dec.26th, 2004

Why aren't tsunamis seen at sea or from the air?

It is a well known fact that tsunami waves have very low amplitudes and large wavelengths while offshore due to larger

volume of surrounding water.

A typical offshore tsunami wave can have an amplitude A of 1M and a wavelength L of the order of 799.9 kMS. So the energy

associated with these offshore tsunami waves is also very low due

to such lower frequencies, or smaller amplitudes,

these waves are difficult to experience and its virtually impossible

to see them at sea or from air.

Coastal areas affected from tsunami

Chronology of 26.12.04 tsunami happened in the Indian Ocean effected 12 countries

around Bay of Bengal and

beyond

triggered by a quake of magnitude 9.3 with its

epicenter west of Sumatra

The quake lifted the seabed by about 5 meters.

Minutes later the tsunami split sending energy pulses

east towards the Sumatra

coast and west across the

open ocean.

As the leading tsunami raced towards Sumatra ,its speed slowed, its wavelength shortened and its

height rose to around 30metres

In minutes 230,000 people lost their lives, and over 430,000 homes were

reduced to rubble

Chronology of 26.12.04 tsunami

Over 100,000 fishing boats were destroyed. The livelihoods of over 5

million people were thrown into jeopardy

Chronology of 26.12.04 tsunami

More than 2,174 miles

of roads destroyed.

Chronology of 26.12.04 tsunami

What are the factors of destruction from tsunamis? Tsunami causes destruction primarily due to the ultrahigh impacts on structures and other assets.

The basic factors of destruction include, wave impact, erosion , and inundation.

The drag applied by tsunami waves on structures can move them or overturn them.

The presence of high salt concentration in tsunami waves causes corrosion of metallic bodies, which decreases their life ultimately

leading to failure.

Besides the primary destruction, secondary destruction may include fire hazards, and water pollution. Fire hazards may be caused by

severed electricity transmission lines, while damaged oil tankers may

contribute a serious threat to water quality.

Why are locally generated tsunamis so dangerous?

Locally generated tsunami may reach a nearby shore in less than

ten minutes due to their high speeds. There is not sufficient time

for the pacific tsunami warning center or for local authorities to

issue a warning. For people living near the coast, the shaking of

the ground is the only warning that a tsunami may be imminent.

Elements at risk: All structures located within 200 m of the low lying coastal area are most

vulnerable to the direct impact of

The tsunami waves as well as the impact

of debris & boulders brought by it.

Structures constructed of wood, mud, thatch, sheets and structures without

proper anchorage to foundations are

liable to be damaged by tsunami waves &

flooding.

Other elements at risk are infrastructure

facilities like ports &

harbors, telephone and

electricity poles,

cables. Ships & fishing

boats/nets near the

coast also add to the

destruction caused by

tsunami waves.

Elements at risk:

Hazard Mitigation Strategies: Site Planning and Land Management The designation and zoning of tsunami hazard Areas for such open-space uses as agriculture , parks and recreation, or natural

hazard areas is recommended as the first land use planning

Strategy.

This strategy is designed to keep development at a minimum in hazard areas.

Native vegetation may provide defense (e.g., mangroves for Indian Ocean coastline.

Cluster houses in a staggered pattern to allow proper ventilation. Zigzag patterns avoid wind tunnel effects.

Seawalls and Bulkheads These are structures placed parallel or nearly parallel to the shoreline to separate the land area from water area.

The primary purpose of a bulkhead is to retain or prevent sliding of the land.

Seawalls are necessarily

massive and

expensive and

should be

constructed only

where the

adjoining shore is

highly developed

and storm attack

is severe.

Building orientationlearning from the tsunami. The shortest length of building should face the water. allows

the water to move around the structure as efficiently as

possible. The building can also act as a water diverter.

coast line water flow raised platform

Structures that allow water to move through them: All new buildings must be elevated on pilings, posts, piers, or

columns.

The Spa at the Lighthouse Hotel. The building sustained minor damage during the tsunami, because it had many openings, water moved through it easily.

Pile foundations use long slender

wood, steel, or reinforced concrete

piles that are driven or jetted into the

ground.

Structures that allow water to move through them: As most of the structures along the coast area comprises of fisherman community, which are constructed of light weight

materials without any engineering inputs.

Therefore ,there is an urgent need to educate the community about the good construction practices that they should adopt

such as:

Site selection avoid building or living in buildings within several 100ft of the coastline

as these are more likely to experience damage

from tsunami.

Construct the structure on a higher ground level with respect to mean sea level.

Elevate coastal homes: most tsunami waves are less than 3 meters in height . elevating house

will help reduce damage to property from most

tsunamis. Structural columns resist the impact

while other walls are expendable.

Construction of community halls at higher locations , which can act as shelters at the time of a disaster.

note that adequate measures are also brought into the design to cater earthquake forces .

Construction of water breakers to reduce the velocity of waves. Use of water and corrosion resistant materials for construction.

Tsunami proof house

Improving in technology has enabled man to build tsunami proof houses

which can reduce damage created to ones property one of the most common houses are built as follows :-

Coastal homes are elevated

battery walls can be put .

There must be deep protection to the foundation of the buildings.

These are built in hydrodynamics

structure which ensures easy flow

of water and protect homes from

collapsing .

Detection & Warning

- Monitor Earthquake Zones

- Tsunami Warning Systems

a) Seismographs to detect earthquakes

b) Tidal gauges to determine sea level

changes

c) Byud sensors to detect tsunami in open

ocean

Structural Controls

water gate byuo mones house

Land use

- Native vegetation may provide defense

(e.g., mangroves for Indian Ocean

coastline); protection of coral reefs

- Development of land must be

monitored

Run-up maps

- Show the height to which water is

likely to rise

Tsunami-ready status

- Establish emergency operation center

- Promote community awareness

program

Detecting tsunami

- only some machines have been introduced

to detect tsunami which mainly depend on

satellites and sonar to detect tsunami.

- Many measures have been taken to

reduce damage created by tsunami.

Government has been giving education to

the coastal people about the dos and don'ts during tsunami.

- many boards have been put up to warn

the people before entering tsunami prone

area