V.r Earthquake

EARTHQUAKE

V.RAMALINGAM ENV.EDN.CELL STATE TRAINING CENTRE DIRECTORATE OF SCHOOL EDUCATION PONDICHERRY

WHAT IS EARTHQUAKE?

A sudden slipping or movement of a portion of the Earth’s crust, caused by a sudden release of stresses, usually less than 25 miles below the surface.

Anguis h

Terror

Pain Fear

Desperation

Worry Panic Distress Sadness

Horror

Misery Grief

The understanding of the world in the 18th century was different from today …

Depth and Temperature Structure of the Earth

Depth

Temperature

Mantle

2900 Km

870°C

Outer core

5150 Km

4400-6100°C

Inner core

6400 Km

7000°C

The Earth is a dynamic or constantly changing planet. The thin, fragile plates slide very slowly on the mantle's upper layer. This sliding of the plates is caused by the mantle's convection currents slowly turning over and over. This overturn is like a conveyor belt that moves the plates of the crust. These plates are in constant motion causing earthquakes, mountain building, volcanism, the production of "new" crust and the destruction of "old" crust. The following cards will teach you more about the Earth's plates.

What’s a Fault? A fault is a break in the rock that makes up the Earth’s crust. The surfaces on either side of the break move past each other, becoming displaced.

Types of Faults Dip Slips Change in vertical direction (up and down).

Thrust Fault

Normal Fault

Types of Faults Strike Slips Change in horizontal direction (side to side). Right-lateral

Left-lateral

Faults

An earthquake is a sudden, rapid shaking of the Earth caused by the release of energy stored in rocks. This energy can be built up and stored for many years and then released in seconds or minutes.

The plates are locked together, unable to release the accumulating energy. When the accumulated energy grows strong enough, the plates break free causing the ground to shake. Most earthquakes occur at the boundaries where the plates meet; however, some earthquakes occur in the middle of plates.

Earthquakes strike suddenly, without warning. Earthquakes can occur at any time of the year and at any time of the day or night. On a yearly basis, 70 to 75 damaging earthquakes occur throughout the world.

Ground shaking from earthquakes can collapse buildings and bridges; disrupt gas, electric, and phone service; and sometimes trigger landslides, avalanches, flash floods, fires, and huge, destructive ocean waves (tsunamis).

 Focus & Epicenter EPICENTRE T CRUS

CRU ST

Earth’s surface

FOCUS

HYPOCENTER MANTLE

The point where the earthquakes are generated is called focus or Hypocentre. The point on the earth’s surface, directly above the focus, is called the epicenter .

250 millions years ago the Earth's seven continents were all grouped together into a supercontinent called Pangea. Notice the postion of the continents of Antarctica (Far north of its current position), Australia (flipped sideways and far west of its current position) and the subcontinent of India (Hundreds of miles from Asia).

180 Million Years Ago

135 Million Years Ago

The plates are still moving today making the Atlantic Ocean larger and the Pacific Ocean smaller. The yellow arrows on the world map indicate the direction of plates movements today.

COMPLEX PLATE BOUNDARY ZONE IN SOUTHEAST ASIA Northward motion of India deforms all of the region Many small plates (microplates) and blocks

The Indian plate crashed into the Eurasian plate with such speed and force that it created the tallest mountain range on Earth, the Himalayas! What do you predict the world will look like in 100 million or 200 million years? What new mountain ranges will form?

The Earth's crust is broken into many pieces. These pieces are called plates . There are twelve main plates on the Earth's surface. The lines on this map of the world represent the largest plate boundaries.

Tectonic Plates of the World 4 1 12

10 13

11

6

9 6

Legend 1 – North American Plate 2 – South American Plate 3 – African Plate 4 – Eurasian Plate 5 – Indo-Australian Plate 6 – Pacific Plate 7 – Antarctic Plate 8 – Nazca Plate 9 – Cocos Plate 10 – Caribbean Plate 11 – Philippine Plate 12 – Juan de Fuca Plate 13 – Arabian Plate 14 – Scotia Plate

3 2

8

5

6

14

7

What is the Ring of Fire? The Pacific Ring of Fire is an area of frequent earthquakes and volcanic eruptions encircling the basin of the Pacific Ocean. The Ring of Fire has 452 volcanoes and is home to over 50% of the world's active and dormant volcanoes. Ninety percent of the world's earthquakes and 81% of the world's largest earthquakes occur along the Ring of Fire.

Earthquake Facts

Deadliest earthquakes^ Rank Earthquake

mag. Country

Date

Fatalitie s

1

"Shaanxi"

8

China

January 23, 1556 830,000

2

"Tangshan"

7.8

China

July 27, 1976

242,000

3

"Indian Ocean"

9.1

nr. Indonesia

December 26, 2004

230,210

4

"Aleppo"

8.5

Syria

August 9, 1138

230,000

5

"Damghan"

?

Iran

December 22, 856

200,000

"Haiyuan"

8.6

China

December 16, 1920

200

1.The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960.

The world's deadliest recorded earthquake occurred in 1556 in central China. killing an estimated 8,30,000 people.

In 1976 another deadly earthquake struck in Tangshan, China, where more than 2,50,000 people were killed.

The first “ pendulum seismoscope " to measure the shaking of the ground during an earthquake was developed in 1751, and it wasn't until 1855 that faults were recognized as the source of earthquakes.

WHEN WAVES ARRIVE

Seismograph

Mercalli (MM) Scale Categories Modified :

I.

Felt only by a very few people under especially favorable circumstances

II. Felt only by a few people at rest, especially on the upper floors of buildings. Suspended objects may swing. III. Felt quite noticeably indoors. Standing motor vehicles may rock slightly. Vibration like the passing of a truck. IV. Felt indoors by many, outdoors by a few. At night, some awakened. Crockery, glassware, windows, doors rattle. V. Felt by nearly everyone; damage to contents and structures uncommon but possible.

VI. Felt

by all; many frightened and run outdoors; damage slight.

VII. Everybody runs outdoors; damage negligible to buildings seismically well-designed and constructed; slight to moderate to ordinary structures; considerable damage to poorly built or badly designed structures.

VIII. Damage slight in well-designed, considerable in ordinary, and great in poorly built structures; chimneys, monuments, walls, etc., fall.

IX. Damage considerable to well-designed structures, and great (including partial or complete collapse) in other buildings; buildings shifted off foundations; underground pipelines disrupted. X. Some well-built wooden structures destroyed; most masonry and ordinary structures destroyed; railroad tracks bent; landslides common; water spills over banks of streams, lakes, etc. XI. Few, if any, masonry structures remain standing; bridges are destroyed; broad fissures open in the ground; underground pipelines are completely out of service; earth subsides. XII. Damage is total; waves are seen propagating along surface of the ground; nearly impossible to stand; objects thrown up into the air.

Richter Scale • Small: 5.0 to 5.9 • Moderate: 6.0 to 6.9 • Major: 7.0 to 7.9 • Great: 8.0 or greater

ground acceleration

In 1935 Charles Richter developed a method to compare the sizes of earthquakes based on waves recorded by seismographs.

Modern seismologists have modified his method and now analyze all waves recorded on a seismograph to produce a seismic moment. The seismic moment is then converted to moment

magnitude, which is the standard size reported by the U.S. Geological Survey.

nderstanding Magnitude

How does the amplitude of a magnitude-9 earthquake compare to the amplitude of smaller events? If we likened earthquakes to hills and mountain peaks... Each peak is (approximately) 10 times the height of the previous one.

Mag. 7

Mag. 8 = 10x larger than Mag 7

Mag. 9 = 10x larger than Mag. 8 = 100x larger than Mag. 7

The earliest recorded evidence of an earthquake has been traced back to 1831 BC in China, but there is a fairly complete record starting in 780 BC during the Zhou Dynasty in China.

India Earthquake Prone- WHY •India was placed on

Indo-Australian plate.

•The plate snapped. •Indian subcontinent started shifting upwards.

•Stresses are

continuously developed north of India.

•With rupture of Indo-

Eurasia plate in Bay of

5 6

INDIA Seismic Zones

7 8 9

Seismic Zone Map of India: Year-1962

Seismic Zone Map of India: -1966

Seismic Zone Map of India: -1970

AFTER TSUNAMI

Fig: 2.1.6

VULNERABILITY

• 1819 Gujarat [Kutch] 8.0 (2000 death

• 2001 Gujarat [Bhuj] 6.9 (13805 death • Increased vulnerability in two centurie

You can never tell when there will be an earthquake, but you can reduce or avoid damage, injuries or loss of life by preparing yourself.

Latest Earthquakes in the World - Past 7 days

Wednesday, August 05, 2009 at 21:43:24 UTC Thursday, August 06, 2009 at 06:43:24 AM at epicenter Location : Depth Magnitude

38.844°S, 137.201°E 4.4 km (2.7 miles) 5.0

DISTANCE 450 km (280 miles) SSW of ADELAIDE, South Australia, Australia

TIME OF EARTHQUAKE IN OTHER TIME ZONES

Wednesday, August 05, 2009 at 21:43:27 (UTC) - Coordinated Universal Time Thursday, August 06, 2009 at 06:43:27 AM local time at epicenter

Thursday, August 06, 2009 at 03:13:27 AM - Delhi, Bombay, Calcutta

Recent Earthquakes - Last 8-30 Days

It was recognized as early as 350 BC by the Greek scientist Aristotle that soft ground shakes more than hard rock in an earthquake.

Moonquakes ("earthquakes" on the moon) do occur, but they happen less frequently and have smaller magnitudes than earthquakes on the Earth.

The lunar seismometer (lower right) carried aboard Apollo 16.

The lunar seismometer (lower right) carried aboard Apollo 16.

Slip on an earthquake fault START Surface of the earth

Depth Into the earth

✭ 100 km (60 miles) Distance along the fault plane

Slip on an earthquake fault Second 2.0

Slip on an earthquake fault Second 4.0

Slip on an earthquake fault Second 6.0

Slip on an earthquake fault Second 8.0

Slip on an earthquake fault Second 10.0

Slip on an earthquake fault Second 12.0

Slip on an earthquake fault Second 14.0

Slip on an earthquake fault Second 16.0

Slip on an earthquake fault Second 18.0

Slip on an earthquake fault Second 20.0

Slip on an earthquake fault Second 22.0

Slip on an earthquake fault Second 24.0

The magnitude of an earthquake is a measured value of the earthquake size.

Much of the damage in earthquakes is predictable and preventable. We must all work together in our communities to apply our knowledge to building codes, retrofitting programs, hazard hunts, and neighborhood and family emergency plans.

Alert by the animals Three weeks ago, the water level in a pond 350 miles from the quake's epicentre inexplicably plunged. Three days before disaster struck, thousands of toads appeared on the streets of Mianzhu city, where 2,000 have been reported dead. And hours before, zoo animals in Wuhan began acting bizarrely.

The earliest reference we have to unusual animal behavior prior to a significant earthquake is from Greece in 373 BC. Rates, weasels, snakes, and centipedes reportedly left their homes and headed for safety several days before a destructive earthquake However, consistent and reliable behavior prior to seismic events, and a mechanism explaining how it could work, still eludes us. Most, but not all, scientists pursuing this mystery are in China or Japan.

We can easily explain the cause of unusual animal behavior seconds before humans feel an earthquake. Very few humans notice the smaller P wave that travels the fastest from the earthquake source and arrives before the larger S wave. But many animals with more keen senses are able to feel the P wave seconds before the S wave arrives. As for sensing an impending earthquake days or weeks before it occurs, that's a different story

not isolated

isolated

British tourists said moments before the quake struck the pandas they were watching at the world famous Wolong reserve became agitated.

As China deals with the aftermath, online commentators and bloggers are asking why no heed was paid to these signs. Some suggested officials could have predicted the quake earlier. However, seismologists say it is practically impossible to predict when and where an earthquake will strike.

Erratic Behavior in Dogs Researchers around the world continue to pursue the idea, however. In September 2003 a medical doctor in Japan made headlines with a study that indicated erratic behavior in dogs, such as excessive barking or biting, could be used to forecast quakes. In 373 B.C., historians recorded that animals, including rats, snakes and weasels, deserted the Greek city of Helice in droves just days before a quake devastated the place.

Do you know what would happen before an earthquake?

Bright lights flash in the sky

Animals are too nervous, such as cows, pigs, horses, and snakes, etc.

Predictions of an earthquake: 1) Bright lights flash in the sky; 2) The water in the well rise and fall; 3) The well walls have deep cracks with smelly gas; 4) Animals are too nervous, such as cows, pigs, horses, and snakes, etc; 5) Mice run out to look for places to hide; 6) Fish jump out of the ponds.

• The idea that animals can sense tremors in advance is as old as the ancient Greeks of 373 B.C. and as new as the Asian tsunami of 2004.

Frogs Predict Big Earthquake in China

The Imminent earthquake prediction 1975Haicheng Earthquake Thefirst successful imminent earthquake predictionin humanhistory

Public Notice

There might be an earthquake very soon, the film will be shown in the open air instead of in the cinema. Xinhua Cinema

1975: Liaoning Province, China • First major earthquake to be predicted • Saved thousands of lives • Chinese officials ordered the evacuation of about 1 million people days before the earthquake • Reasons: ·Changes in land elevation and ground water levels for a few months ·Widespread accounts of peculiar animal behavior ·Regional increase in seismic activity

Living with Disasters…

Are we living in a more dangerous world than our grandparents lived?

Living with Disasters…

Or is it becoming a safer place?

Conclusion:

"A chain is as strong as its weakest link”

Let’s make a safer world

References 1.

www.usgs.gov*

for information of the tsunami

www.iris.edu* 2.

www.bbc.com,

www.cnn.com

for animation and photos

serc.carleton.edu, www.kyoto-u.ac.jp 3.

www.digitalglobe.com

for satellite photos

4.

www.asiantsunamivideos.com

for videos of tsunami disaster

* : U.S. Geological Survey * : Incorporated Research Institution for Seismology