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Just-in-Time%20Lecture

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Magnitude 9.0 on Richter scale. 150 km off W coast / N Sumatra Island / Indonesia ... Magnitude 9.0 on Richter scale. The 4th largest earthquake in the world ... – PowerPoint PPT presentation

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Title: Just-in-Time%20Lecture


1
Just-in-Time Lecture Earthquake Tsunami South
Asia, 26 Dec 2004
By Ali Ardalan, Ronald E. LaPorte, Eugene
Shubnikov, Faina Linkov Eric K. Noji
2
  • What is the Disaster Supercourse?
  • What is a JIT lecture?

3
Mission Statement The Global Health Network
Disaster, Network for Tsunamis is designed to
translate the best possible scholarly information
from leading researchers to educators worldwide.
4
  • Lecture objectives
  • To provide the best possible information
  • about the science of South Asian disaster

5
Earthquake Tsunami South Asian
  • Greatest earthquake in 40 years
  • Magnitude 9.0 on Richter scale
  • 150 km off W coast / N Sumatra Island /
    Indonesia
  • Generation of disastrous
  • tsunami in 11 countries
  • bordering Indian Ocean

6
  • History of Great Earthquakes in the Region
  • Along the subduction zone from
    southern Sumatra to the Andaman Islands
  • 2000 M 7.9
  • 1861 M 8.5
  • 1833 M 8.7
  • 1797 M 8.4

USGS
7
  • Magnitude 9.0 on Richter scale
  • The 4th largest earthquake in the world since
    1900
  • The largest since 1964 Alaska earthquake
  • ----------
  • It was felt (VIII) at Banda Aceh, (V) at Medan,
    Sumatra (II-IV) in parts of Bangladesh, India,
    Malaysia, Maldives, Myanmar, Singapore, Sri Lanka
    Thailand.

8
Earthquake Strength Measures I) Magnitude
II) Intensity
  • I) Magnitude
  • Definition A measure of actual physical energy
    release at its source as estimated from
    instrumental observations.
  • Scale Richter Scale
  • By Charles Richter, 1936
  • Open-ended scale
  • The oldest most widely used

Noji 1997
9
Earthquake Strength Measures I)
Magnitude II) Intensity
  • II) Intensity
  • Definition a measure of the felt or perceived
    effects of an earthquake rather than the strength
    of the earthquake itself.
  • Scale Modified Mercalli (MM) scale
  • 12-point scale, ranges from barely perceptible
    earthquakes at MM I to near total destruction
    at MM XII

10
Magnitude versus Intensity
  • Magnitude refers to the force of the earthquake
    as
  • a whole, while intensity refers to the
    effects of an
  • earthquake at a particular site.
  • An earthquake can have just one magnitude, while
  • intensity is usually strongest close to the
    epicenter
  • is weaker the farther a site is from the
    epicenter.
  • The intensity of an earthquake is more germane
    to
  • its public health consequences than its
    magnitude.

11
  • Duration of the Earthquake
  • Actual rupture duration 3- 4 min.
  • Definition The time it took for
  • earthquake to take place on
  • fault rupture entire length

Northern Sumatra Above the fault Felt shaking
Several minutes
USGS
12
Unbelievable !! Earthquake 23,000 Hiroshima
Bombs
  • Released Energy by South Asian Earthquake
  • Es 20X1017 Joules
  • 475 megatons of TNT

USGS
13
Effect of the Earthquake on the Length of
Day -2.676 microseconds Too small to be observed
!
USGS
14
  • Earthquake 26 Dec 2004
  • Max. displacement on the rupture
  • surface between plates 20 m
  • Max. displacement of sea bottom
  • above the quake source 10 m

USGS
15
Rupture a patch along fault's surface by
earthquakes
Larger the rupture patch, Larger the magnitude of
earthquake
as BIG as California !! Patch of fault by
Sumatra-Andaman Islands Earthquake
16
  • How we can estimate the initial size of the
    rupture by an earthquake?
  • By studying
  • Length of the aftershock zone
  • Dimensions of historical earthquakes
  • Generated elastic waves

17
  • Aftershocks
  • As 29 Dec 68 aftershock
  • M 7.1 The largest, 3h after the main shock
  • M 6.0 13 aftershocks
  • The Earthquake Ruptures Length Width
  • Length 1200-1300 km
  • Width gt100 km

USGS
18
  • NO tsunamis by the aftershocks in south Asia
  • Number of aftershocks will decrease with time
  • Number of aftershocks can be quite variable.

Seismologists are not able to predict timing
and sizes of individual aftershocks !
USGS
19
  • Earthquake 26 Dec 2004
  • Location Beneath the Indian Ocean west
  • of Sumatra, Indonesia
  • Epicenter East of the Sunda Trench
  • Overriding plate Burma Plate
  • Subducting plate India Plate

20
What is a Megathrust Earthquake? What is the
Thrust-Faulting? 26 Dec 2004 Result of Thrust -
Faulting
Megathrust earthquakes occur where one
tectonic plate subducts beneath
another.
21
  • Importance of Megathrust Earthquakes
  • World's largest recorded earthquakes have all
  • been megathrust events
  • Often generate large tsunamis that cause
  • damage over a much wider area than is
    directly
  • affected by ground shaking near the
  • earthquake's rupture

NEIC
22
The megathrust earthquake of Dec 26,
2004, occurred on the interface of India and
Burma plates and was caused by the release of
stresses that develop as the India plate subducts
beneath the overriding Burma plate.
NEIC
23
  • History of Megathrust Earthquakes
  • 1960 Chile, M 9.5
  • 1964 Prince William Sound, Alaska, M 9.2
  • 1957 Andreanof Islands, Alaska, M 9.1
  • 1952 Kamchatka, M 9.0

NEIC
24
What is a Tsunami?
  • soo-NAH-mee or Harbor Wave
  • is a Japanese word tsu means
  • harbor nami means wave

25
History of Significant Tsunamis in the
Region 1797 gt 300 fatalities at Padang, M 8.4 EQ
1833 Numerous victims at W Sumatra, M 8.7
EQ 1843 Many fatalities at the coast of Nias
Island 1861 1000s fatalities at W coast of
Sumatra, M 8.5 EQ 1881 Indias eastern coast, M
7.9 EQ 883 36,000 fatalities on islands of
Java Sumatra, Krakatau
explosion 1941 M 7.7 Adaman Islands EQ (
Anecdotal evidence of existing a
tsunami)
USGS
26
NASA
How the earthquake 26 Dec 2004
generated tsunami?
Imagine a fist rising up from under the water.
Water rolls down off the sides of the fist.
When the bottom of the ocean was deformed by this
megathrust quake, the upward force acted like
that fist, creating massive waves of tsunamis,
which spread out in all directions.
27
  • Tsunami 2 Wavefronts
  • Distance 500 - 850 km
  • Height 50 cm

28
Tsunami Waves Height Travel time
  • Height
  • 10 m Coastline of
  • Sumatra, near the
  • fault boundary
  • 4 m Sri Lanka,
  • Thailand, Somalia
  • Seychelles
  • Travel times
  • From minutes (Sumatra)
  • to 8 hours (Somalia)

29
  • Tsunami Distance Damage
  • Distance alone NO guarantee of safety
  • Somalia was hit harder than Bangladesh
  • despite being much farther away.

30
NASA
  • Andaman Islands
  • One of the first affected
  • places, Dec 26
  • 850 km N of epicenter
  • As 3 Jan gt 6000 death

31
The Most Affected Area by the Tsunami NW coast of
Sumatra, Aceh province,
Indonesia
  • 100 km (62 miles)
  • from the epicenter
  • Waves height
  • 15 m. (50 ft.)
  • 80,000 death
  • (1/2 of total)

32
  • Tsunami Sri Lanka India
  • Waves travel time 4h
  • Devastation the island of Sri Lanka off the
  • southeastern tip of India
  • Moving the waves westward toward
  • southeastern India, along a stretch of
    coastline,
  • Coromandel Coast
  • Destruction of cities, towns, and fishing
    villages
  • up and down the coast of state of Tamil Nadu

NASA
33
  • Tsunami Thailand
  • Beaches of Khao Lak struck 2-3 h after
  • the earthquake
  • Location 500 km from the epicenter
  • Waves height 10 m. (33 ft.)

NASA
34
Tsunami Maldives Male, the capital island of
Maldives was severely hit.
35
NO Tsunami Warning Issued on 26 Dec 2004 Disaster
!!
NO Tsunami Warning System exists for the Indian
Ocean !!
36
Knowledge is Safety! Girl's sea warning saved a
hundred fellow tourists at Phuket beach from
tsunami because of a geography lesson about the
giant waves!!
37
The impacts of earthquake tsunami on
South Asia
  • Dead139.290
  • Injured32,327
  • Missed14,950
  • Displaced 1,754,433

WHO
38
We wish to express our warm thanks to GDHNet
faculties and all groups that contributed their
valuable materials.
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