The Great Sumatra Earthquake and Indian Ocean Tsunami of December 26, 2004

1
The Great Sumatra Earthquake and Indian Ocean
Tsunami of December 26, 2004
Earthquake Engineering
Research Institute
An illustrated description of their causes and
effects
2
Preface
This presentation was developed to explain the
origins of the Sumatra earthquake of December 26,
2004 and the ensuing tsunami, and to document the
damages caused by the earthquake and tsunami in
so many countries around the Indian Ocean.

• The presentation was created largely by Widianto,
  a doctoral candidate in civil engineering and
  president of the EERI student chapter at the
  University of Texas at Austin.
• Other contributors include Sarah Nathe, Craig
  Comartin, and Heidi Faison.

This project was supported by funds from the
National Science Foundation through EERIs
Learning From Earthquakes Program under grant
CMS-0131895
3
The 26th December 2004 Sumatra-Andaman
earthquake is the fourth largest earthquake in
the world since 1900 and is the largest since the
1964 Prince William Sound, Alaska earthquake.
United States Geological Survey (USGS)
The tsunami that struck Southeast Asia on
December 26, 2004 has been confirmed as the most
devastating in modern history. Guinness Book
of World Records
4
Contents

• Introduction Plate tectonics, earthquakes
• Sumatra Earthquake
• - Tectonic activity
• - Observations
• - Damage
• Indian Ocean Tsunami
• - Basic mechanism
• - Videos before and after giant wave
  arrival
• - Damage
• Tsunamis in the USA
• Tsunami Risk Reduction
• The Earthquake Engineering Research Institute

5
Introduction Plate Tectonics

• The Earth is characterized by a small number of
  lithospheric plates that float on a viscous
  underlayer called the asthenosphere.
• Geological evidence shows that plates undergo
  constant, gradual change. Magma is continually
  upwelling at the mid-oceanic ridges and rises as
  the seafloor spreads apart.
• In some areas, large sections of plates are
  forced to move beneath other plates (surface
  layers of rocks are absorbed into the earths
  interior). These areas are called subduction
  zones.
• ? A plate being subducted beneath another

6
Introduction Plate Tectonics
Source Earthquakes by Bruce A. Bolt
7
Introduction Plate Tectonics
95 of earthquakes occur along the edges of the
interacting plates
Source Earthquakes by Bruce A. Bolt
8
Worlds Largest Magnitude Earthquakes
Earthquake Magnitude Year Approx. casualties
1. Chile 9.5 1960 gt2000
2. Prince William Sound, Alaska 9.2 1964 ? 125
3. Andreanof Islands, Alaska 9.1 1957 Not reported
4. Kamchatka Peninsula 9.0 1952 Not reported
5. Sumatra 9.0 2004 gt283,100 (gt173,000 in Indonesia)
Source United States Geological Survey (USGS)
9
Earthquake Energy
Sumatra-Andaman (2004)
Source Earthquakes by Bruce A. Bolt
10
Sumatra Earthquake
Magnitude 9.0 Date-time Sunday, December 26,
2004 at 75853 AM (local time) Depth 30 km
(18.6 miles) Distances 250 km (155 miles) SSE
of Aceh, Sumatra, Indonesia 310 km (195 miles)
W of Medan, Sumatra, Indonesia 1260 km (780
miles) SSW of Bangkok, Thailand 1605 km (990
miles) NW of Jakarta, Java, Indonesia
Source United States Geological Survey (USGS)
11
Tectonic Summary

• It occurred on the interface of the India and
  Burma plates an interplate earthquake.
• India plate subducts beneath the overriding
  Burma plate at the Sunda Trench.
• In the region of the earthquake, the India plate
  moves toward the northeast at a rate of about
  6 cm/year relative to the Burma plate.
• Thrust faulting caused the earthquake (slip
  directed perpendicular to the trench).
• Fault rupture propagated to the northwest from
  the epicenter with a width ? 100 km and an
  average displacement on the fault plane ? 20
  meters.

6 cm/yr
Source United States Geological Survey (USGS)
12
Felt Shaking Reports

• Modified Mercalli Intensity Scale

Source United States Geological Survey (USGS)

• Banda Aceh, Sumatra IX
• Medan, Sumatra IV
• Port Blair, Andaman Islands VII

• Subsidence and landslides were observed in
  Sumatra.
• A mud volcano near Baratang, Andaman Islands
  began erupting on December 28, 2004.
• Intensity vs. Distance from Epicenter Plot

13
Aftershock Zone

• Extends from Northern Sumatra to the Andaman
  Islands, 1300 km to the north.
• Largest aftershock directly following the main
  shock was M 7.1 in the Nicobar Islands.
• On March 28, 2005, a M 8.7 earthquake occurred
  in a region of the fault southeast of the Dec
  26th mainshock and its rupture zone.

Epicenter of mainshock, 28 Mar 2005
14
Earthquake Damage
Location Banda Aceh, Sumatra, Indonesia
Photo Jose Borrero
Structural damage to concrete frame building.
15
Earthquake Damage
Location Banda Aceh, Sumatra, Indonesia
Photo Murat Saatcioglu, Ahmed Ghobarah, Ioan
Nistor
Partial collapse of concrete frame building due
to column failure.
16
Earthquake Damage
Location Banda Aceh, Sumatra, Indonesia
Photos Murat Saatcioglu, Ahmed Ghobarah, Ioan
Nistor
Partial collapse of concrete frame building due
inadequate column reinforcement.
17
Earthquake Damage
Location Banda Aceh, Sumatra, Indonesia
Architectural damage to the Grand Mosque tower.
Photo Jose Borrero
18
Earthquake Damage
Location Port Blair, Andaman Islands
Column of residential building damaged by ground
motion.
Source Geological Survey of India
19
Earthquake Damage
Longitudinal (50 m long) crack on Kamraj Road
after the earthquake
Location Port Blair, Andaman Islands
Major crack showing a rupture width of 15 cm on
Kamraj Road after the earthquake
Source Geological Survey of India
20
Earthquake and Tsunami
Not all earthquakes generate tsunamis. An
earthquake must have certain characteristics in
order to generate a tsunami
1. Epicenter is underneath or near the ocean. 2.
Fault causes vertical movement of the sea floor
(up to several meters) over a large area
(up to 100,000 km2). 3. Large magnitude ( gt 7.5 )
AND shallow focus ( lt 70 km).
Source Earthquakes by Bruce A. Bolt
21
Basic Tsunami Mechanism

• An earthquake causes a vertical movement of the
  seafloor, which displaces the sea water.

• Large waves then radiate from the epicenter in
  all directions.

22
Tsunami Explained

• A tsunami is series of traveling ocean waves of
  extremely long length generated primarily by
  earthquakes occurring below or near the ocean
  floor.
• Tsunami waves propagate across the deep ocean
  with a speed exceeding 800 km/h (? 500 mph) and a
  wave height of only a few tens of centimeters or
  less.
• As they reach the shallow waters of the coast,
  the waves slow down and their height increases up
  to tens of meters (30 ft) or more.

Source NOAA
23
Tsunami Translated
Japanese word
Tsu means harbor
English translation Harbor wave
Nami means wave

• Tidal wave is a misnomer because the cause is
  unrelated to tides.
• Seismic sea wave is misleading because a
  tsunami can be caused by non-seismic events, and
  it is not dangerous in the open ocean.

24
Water Recession A Precursor
Draw Down Effect
Wave Generation
From Nature Publishing Group
From Nature Publishing Group
Kalutara Beach, Sri Lanka
From Digital Globe
25
Tsunami Wave Appearance
Source www.waveofdestruction.org

• A tsunami wave crest has three general
  appearances from shore
• Fast-rising tide
• Cresting wave
• A step-like change in the water level that
  advances rapidly (called a bore)

A bore on the Qian Tang Jiang River, China

• Series of waves
• Most tsunamis come in a series of waves that may
  last for several hours
• The outflow of water back to the sea between
  waves can cause more damage than the original
  incoming wave fronts
• The first wave is rarely the largest

26
Tsunami Propagation
National Institute of Advanced Industrial Science
and Technology, Japan
27
Tsunami Damage
Location Lhoknga, Indonesia
Before Tsunami January 10, 2003
After Tsunami December 29, 2004
Source National University of Singapore
28
Tsunami Damage
Location Lhoknga, Indonesia
Exposed bridge piers of road that washed away.
Photo Jose Borrero
High Water Mark
Overturned ship
Damage zone showing an overturned tanker, trees
snapped in half, and the high water mark on
islands where vegetation was stripped away.
Broken Trees
Photo Jose Borrero
29
Tsunami Damage
Location Gleebruk, Indonesia
Before Tsunami April 12, 2004
After Tsunami January 2, 2005
Source Digital Globe
30
Tsunami Damage
Before Tsunami April 12, 2004
After Tsunami January 2, 2005
Source Digital Globe
31
Tsunami Damage
Location Banda Aceh, Indonesia
Before Tsunami June 23, 2004
After Tsunami December 28, 2004
Source Digital Globe
32
Tsunami Damage
Location Banda Aceh, Indonesia
A boat was lifted on top of houses by the waves.
Photo Jose Borrero
Damage was caused by both water and water-borne
debris.
Photo Jose Borrero
33
Tsunami Damage
Location Banda Aceh Lhoknga, Indonesia
The tsunami waves came from many directions and
flowed across the tip of northeastern Sumatra.
Graphic Jose Borrero
34
Tsunami Damage
Location Thailand
Thailand
Damage to Kao Lak Resort from tsunami waves.
Photo Curt Edwards
Despite the presence of debris, this naval base
building had little structural damage due to a
retaining wall at its frontage.
Photo Chitr Lilavivat
35
Tsunami Damage
Location Sri Lanka
Flow depths were about 4.5 m at Yala Safari
Resort, where water levels were determined by
debris in the trees (see door impaled on branch).
Sri Lanka
Damage to house in Tangala.
36
Tsunami Damage
Location Kerala, India
The collapsed front portion of a concrete house.
In the village of Alappad, the foundations and
the soil beneath many of the houses were scoured
out.
Source Geological Survey of India
37
Tsunamis in the U.S.A.

• The west coast, from California to Alaska, is
  vulnerable to tsunamis from nearby or distant
  earthquakes.
• Hawaii is extremely vulnerable to all tsunamis in
  the Pacific Ocean.
• California, Oregon, Washington, Alaska and Hawaii
  all have tsunami education programs for residents
  and visitors, coastal signage, and warning
  response plans.

Photo Eugene Schader, NISEE Collection
Photo Kirkpatrick, NISEE Collection
Warped pier in Crescent City, CA caused by 1964
Alaska earthquake tsunami
Tsunami induced damage in Seward, Alaska from
1964 Alaska earthquake
38
Historical Tsunamis in the U.S.A.
Tsunami Source Year Affected States Tsunami Casualties
Cascadia Fault Earthquake 1700 West coast unknown
Aleutian Earthquake (Mw 8.3) 1946 AK, HI , WA, OR, CA 159 (Hilo, Hawaii) 165 (total)
Lituya Bay, Alaska Landslide 1958 AK 2
Chile Earthquake (Mw 9.5) 1960 CA, HI 61 (Hilo, Hawaii)
Alaska Earthquake (Mw 9.3) 1964 AK, HI , WA, CA 120 (total)
Sources NOVA International Tsunami Information
Center (ITIC)
39
Tsunami Risk Reduction

• Determine understand community tsunami risk
• Hazard
• Study the shape of the sea floor and the coastal
  topography
• Run simulations of tsunamis
• Vulnerability
• Develop maps of potential risk areas
• Exposure
• Costal communities, especially with tsunami
  history

risk

• Avoid new development in tsunami run-up areas
• Designate risk areas as open-space, i.e., parks
  and agriculture
• Zone to minimize human risk
• Low density residential zoning
• Large single-residence lots

city planning
40
Tsunami Risk Reduction

• Locate and configure new development in the
  run-up areas to minimize future tsunami losses

site planning

• Avoid inundation areas
• i.e. build on high ground
• Slowing water currents
• i.e. Conserve or replant coastal belts
• of forest and mangrove swamps
• Steering water forces
• i.e. angled, by-pass walls
• Blocking water forces
• i.e. Build sea walls

SLOWING
STEERING
Source National Tsunami Hazard Mitigation
Program (NTHMP)
BLOCKING
41
Tsunami Risk Reduction

• Design and construct new buildings to minimize
  tsunami damage
• Heavy and rigid structure
• Raise building on stilts
• Many openings on the
• ground floor
• Orient perpendicular to the
• shoreline

tsunami-resistant building
Use caution with this design in areas with high
earthquake-shaking risk.
42
Tsunami Risk Reduction
4. Tsunami-resistant buildings (cont.)
Tsunami forces on structures
Structure designed to resist tsunami forces
Source National Tsunami Hazard Mitigation
Program (NTHMP)
43
Caveat Remember Earthquake-Resistant Design
Principles

• Most communities at risk from tsunamis are also
  at risk from damaging earthquakes
• Buildings designed well for earthquakes typically
  perform well in tsunamis

Photo Jose Borrero
Photo Jose Borrero
Well-designed building withstood tsunami forces
without collapse in Banda Aceh, Indonesia
Well-designed building standing amidst the rubble
in Banda Aceh, Indonesia
44
Tsunami Risk Reduction

• Protect existing development through
  redevelopment, retrofit, and land reuse plans and
  projects
• Take special precautions in locating and
  designing infrastructure and critical facilities
• Locate critical infrastructure (water plants,
  hospitals, etc) outside the tsunami danger zone
• Relocate or protect critical infrastructure
• Plan for emergency and recovery

city planning
city planning
45
Tsunami Risk Reduction

• Plan for Evacuation
• Identify vertical evacuation buildings
• Create horizontal evacuation routes
• Develop early warning systems
• Educate and inform public

warning
46
Tsunami Risk Reduction
Tsunami early warning system

• Pressure sensors sit on the ocean bottom and
  measure the weight of water column above them.
• If a tsunami passes overhead, the pressure
  increases and the sensor sends a signal to a buoy
  sitting on the sea surface.
• The buoy then sends a signal to a satellite,
  which in turn alerts a staffed early warning
  center.

47
Tsunami Risk Reduction
The least expensive and the most important
mitigation effort is
EDUCATION
"Even without a warning system, even in places
where they didn't feel the earthquake, if people
had simply understood that when you see the water
go down, when you hear a rumble from the coast,
you don't go down to investigate, you grab your
babies and run for your life, many lives would
have been saved." Lori Dengler, Humboldt State
University New Scientist Magazine January 15,
2005
48
The power of knowledge

• Victor Desosa saved the village of Galbokka in
  Sri Lanka because he knew what to do when the
  water receded.
• Only one inhabitant in his village was killed.
• Casualty rates in nearby villages were 70 90

49
Natural hazards are inevitable. Natural
disasters are not.
John Filson, USGS retired New York Times December
27, 2004
50
Earthquake EngineeringResearch Institute

• EERI is a professional, association dedicated to
  reducing earthquake risk.
• Members of EERI work in the many different fields
  of research and professional practice dedicated
  to reducing earthquake losses.

51
EERI Programs

• Publications Website, Monthly Newsletter and
  Quarterly Technical Journal--Earthquake Spectra
• Technical Seminars National Conferences
• Web based World Housing Encyclopedia
• 5 Regional Chapters -- Political Advocacy
• 20 Student Chapters
• Learning From Earthquakes Program
• Field reconnaissance of earthquake impacts to
  learn lessons for research and practice

To contact us or become a member of EERI, visit
our website www.eeri.org
52
References

• United States Geological Survey (USGS)
• U.S. National Oceanic and Atmospheric
  Administration (NOAA)
• UNESCO / Intergovernmental Oceanographic
  Commission (IOC)
• International Tsunami Information Center (ITIC)
• Laboratoire de Geophysique, France (LDG)
• Earthquakes A Primer, Bruce A . Bolt, W.H.
  Freeman, 1978
• Digital Globe
• Geological Survey of India
• National University of Singapore
• New Scientist magazine, Issue 2482, January 15,
  2005
• BBC News
• Nature, Vol. 433, January 27, 2005, Nature
  Publishing Group
• Sri Lanka Reconnaissance Teams
  http//walrus.wr.usgs.gov/tsunami/srilanka05/
  http//www.gtsav.gatech.edu/cee/groups/tsunami/i
  ndex.html

53
References (cont.)

• Natural Tsunami Hazard Mitigation Program
  (NTHMP), Designing for Tsunamis, March 2001
• National Information Service for Earthquake
  Engineering (NISEE), Earthquake Image Database,
  Karl Steinbrugge Collection
• www.wavesofdestruction.org
• Field Survey of Northern Sumatra, Jose Borrero,
  EERI Newsletter, March 2005
• Pacific Tsunami Museum
• NOVA The Wave that Shook the World, PBS
  http//www.pbs.org/wgbh/nova/tsunami/
• Metro TV, Surabaya Citra Televisi Indonesia
  (SCTV), Rajawali Citra Televisi Indonesia (RCTI)
• Prof. Wiratman Wangsadinata, Wiratman
  Associates Consulting Company, Indonesia
• EERIs Virtual Clearinghouse http//www.eeri.org/
  lfe/clearinghouse/sumatra_tsunami/overview.html