EarthquakeEarthquake EngineeringEngineering ResearchResearch InstituteInstitute
TheThe GreatGreat SumatraSumatra EarthquakeEarthquake andand IndianIndian OceanOcean TsunamiTsunami ofof DecemberDecember 26,26, 20042004
An illustrated description of their causes and effects PrefacePreface 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.
¾ 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.
¾ Other contributors include Sarah Nathe, Craig Comartin, and Heidi Faison.
This project was supported by funds from the National Science Foundation through EERI’s Learning From Earthquakes Program under grant # CMS-0131895 “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 Contents ¾ Introduction: Plate tectonics, earthquakes ¾ Sumatra Earthquake - Tectonic activity - Observations - Damage ¾ Indian Ocean Tsunami - Basic mechanism - Videos: before and after giant wave arrival - Damage ¾ Tsunamis in the USA ¾ Tsunami Risk Reduction ¾ The Earthquake Engineering Research Institute Introduction – Plate Tectonics ¾ The Earth is characterized by a small number of lithospheric plates that float on a viscous underlayer called the asthenosphere. ¾ 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. ¾ In some areas, large sections of plates are forced to move beneath other plates (surface layers of rocks are absorbed into the earth’s interior). These areas are called subduction zones. Ø A plate being subducted beneath another Introduction – Plate Tectonics
Source: Earthquakes by Bruce A. Bolt Introduction – Plate Tectonics
95% of earthquakes occur along the edges of the interacting plates
Source: Earthquakes by Bruce A. Bolt World’s Largest Magnitude Earthquakes
Earthquake Magnitude Year Approx. casualties 1. Chile 9.5 1960 >2000 2. Prince William 9.2 1964 ≅ 125 Sound, Alaska 3. Andreanof 9.1 1957 Not reported Islands, Alaska 4. Kamchatka 9.0 1952 Not reported Peninsula 5. Sumatra 9.0 2004 >283,100 (>173,000 in Indonesia)
Source: United States Geological Survey (USGS) Earthquake Energy
Sumatra-Andaman (2004)
Source: Earthquakes by Bruce A. Bolt Sumatra Earthquake
Magnitude: 9.0 Date-time: Sunday, December 26, 2004 at 7:58:53 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) Tectonic Summary
¾ It occurred on the interface of the India and Burma plates: an interplate earthquake. ¾ India plate subducts beneath the overriding Burma plate at the Sunda Trench. ¾ 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. ¾ Thrust faulting caused the 6 cm/yr earthquake (slip directed perpendicular to the trench). ¾ Fault rupture propagated to the northwest from the epicenter with a width ≅ 100 km and an average displacement on the fault Source: United States Geological Survey (USGS) plane ≅ 20 meters. Felt Shaking Reports
¾Modified Mercalli Intensity Scale: Source: United States Geological Survey (USGS)
Banda Aceh, Sumatra: IX Medan, Sumatra: IV Port Blair, Andaman Islands: VII ¾ Subsidence and landslides were observed in Sumatra. ¾ A mud volcano near Baratang, Andaman Islands began erupting on December 28, 2004. ¾ Intensity vs. Distance from Epicenter Plot : AftershockAftershock ZoneZone
¾ Extends from Northern Sumatra to the Andaman Islands, ~ 1300 km to the north.
¾ Largest aftershock directly following the main shock was M = 7.1 in the Nicobar Islands.
¾On March 28, 2005, a M = 8.7 earthquake occurred in a region of Epicenter of mainshock, the fault southeast of 28 Mar 2005 the Dec 26th mainshock and its rupture zone. EarthquakeEarthquake DamageDamage
Location: Banda Aceh, Sumatra, Indonesia
Banda Aceh
epicenter
Photo: Jose Borrero Structural damage to concrete frame building. EarthquakeEarthquake DamageDamage
Location: Banda Aceh, Sumatra, Indonesia
Banda Aceh
epicenter
Photo: Murat Saatcioglu, Ahmed Ghobarah, Ioan Nistor
Partial collapse of concrete frame building due to column failure. EarthquakeEarthquake DamageDamage Location: Banda Aceh Sumatra, Indonesia
Banda Aceh
epicenter
Photos: Murat Saatcioglu, Ahmed Ghobarah, Ioan Nistor
Partial collapse of concrete frame building due inadequate column reinforcement. EarthquakeEarthquake DamageDamage
Location: Banda Aceh, Sumatra, Indonesia
Banda Aceh
epicenter
Architectural damage to the Photo: Jose Borrero Grand Mosque tower. EarthquakeEarthquake DamageDamage
Location: Port Blair, Andaman Islands
Port Blair
epicenter
Column of residential building damaged by ground motion.
Source: Geological Survey of India EarthquakeEarthquake DamageDamage
Longitudinal (50 m long) Location: Port Blair, crack on Kamraj Road after Andaman Islands the earthquake Port Blair
epicenter
Major crack showing a rupture width of 15 cm on Kamraj Road after the earthquake Source: Geological Survey of India 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 ( > 7.5 ) AND shallow focus ( < 70 km).
Source: Earthquakes by Bruce A. Bolt Basic Tsunami Mechanism
¾ An earthquake causes a vertical movement of the seafloor, which displaces the sea water.
¾ Large waves then radiate from the epicenter in all directions. Tsunami Explained ¾ A tsunami is series of traveling ocean waves of extremely long length generated primarily by earthquakes occurring below or near the ocean floor. ¾ 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. ¾ 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 Tsunami Translated
Japanese word:
“Tsu“ means “harbor” English translation: “Nami“ means “Harbor wave” “wave”
¾ “Tidal wave” is a misnomer because the cause is unrelated to tides. ¾ “Seismic sea wave” is misleading because a tsunami can be caused by non-seismic events, and it is not dangerous in the open ocean. Water Recession: A Precursor
Wave Generation Draw Down Effect
From: Nature Publishing Group From: Nature Publishing Group
Kalutara Beach, Sri Lanka
From: Digital Globe TsunamiTsunami WaveWave AppearanceAppearance
Source: www.waveofdestruction.org ¾ 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 ¾ 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 Tsunami Propagation
National Institute of Advanced Industrial Science and Technology, Japan TsunamiTsunami DamageDamage
Location: Lhoknga, Indonesia
Lhoknga Before Tsunami January 10, 2003 epicenter
After Tsunami December 29, 2004
Source: National University of Singapore TsunamiTsunami DamageDamage Location: Lhoknga, Indonesia
Lhoknga
Exposed bridge piers of road that
Photo: Jose Borrero washed away. epicenter
High Water Mark Overturned ship Damage zone showing an overturned tanker, trees snapped in half, and the high water mark on islands Broken Trees where vegetation was stripped away. Photo: Jose Borrero TsunamiTsunami DamageDamage
Location: Gleebruk, Indonesia
Gleebruk Before Tsunami April 12, 2004
epicenter
After Tsunami January 2, 2005
Source: Digital Globe TsunamiTsunami DamageDamage G leeb ru k
ep ic en ter
Before Tsunami April 12, 2004
After Tsunami January 2, 2005
Source: Digital Globe TsunamiTsunami DamageDamage Location: Banda Aceh, Indonesia
Banda Aceh
Before Tsunami June 23, 2004 epicenter
After Tsunami December 28, 2004
Source: Digital Globe TsunamiTsunami DamageDamage Location: Banda Aceh, Indonesia
Banda Aceh A boat was lifted on top of houses by the
Photo: Jose Borrero waves. epicenter
Damage was caused by both water and water-borne debris. Photo: Jose Borrero TsunamiTsunami DamageDamage
Location: Banda Aceh & Lhoknga, Indonesia
Banda Aceh
ep icen ter
The tsunami waves came from many directions and flowed across the tip of northeastern Sumatra.
Graphic: Jose Borrero TsunamiTsunami DamageDamage
Location: Thailand
KeThailandrala Coast Damage to Kao Lak Resort from tsunami waves.
epicenter
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 TsunamiTsunami DamageDamage
Location: Sri Lanka
Flow depths were
about 4.5 m at Yala KeSrira lLankaa Coast Safari Resort, where water levels were determined by debris in the trees (see door impaled on branch). epicenter
Damage to house in Tangala. TsunamiTsunami DamageDamage Location: Kerala, India
Kerala Coast
The collapsed front portion of a concrete
house. epicenter
In the village of Alappad, the foundations and the soil beneath many of the houses were scoured out.
Source: Geological Survey of India TsunamisTsunamis inin thethe U.S.A.U.S.A. ¾ The west coast, from California to Alaska, is vulnerable to tsunamis from nearby or distant earthquakes. ¾ Hawaii is extremely vulnerable to all tsunamis in the Pacific Ocean. ¾ California, Oregon, WashingtonWashington,, Alaska and Hawaii all have tsunami education programs for residents and visitors, coastal signage, and warning response plans.
Photo: Kirkpatrick, NISEE Collection Photo: Eugene Schader, NISEE Collection
Tsunami induced damage in Seward, Alaska Warped pier in Crescent City, CA caused by from 1964 Alaska earthquake 1964 Alaska earthquake tsunami HistoricalHistorical TsunamisTsunamis inin thethe U.S.A.U.S.A.
Tsunami Source Year Affected States Tsunami Casualties
Cascadia Fault 1700 West coast unknown Earthquake
Aleutian Earthquake 1946 AK, HI , WA, OR, CA 159 (Hilo, Hawaii) (Mw = 8.3) 165 (total)
Lituya Bay, Alaska 1958 AK 2 Landslide
Chile Earthquake 1960 CA, HI 61 (Hilo, Hawaii) (Mw = 9.5)
Alaska Earthquake 1964 AK, HI , WA, CA 120 (total) (Mw = 9.3)
Sources: NOVA; International Tsunami Information Center (ITIC) TsunamiTsunami RiskRisk ReductionReduction
1.1. Determine & understand community tsunami risk ¾ Hazard: Study the shape of the sea floor and the coastal topography Run simulations of tsunamis ¾ Vulnerability: Develop maps of potential risk areas ¾ Exposure: Costal communities, especially with tsunami history
2.2. Avoid new development in tsunami run-up areas 1. Designate risk areas as open-space, i.e., parks and agriculture 2. Zone to minimize human risk 1. Low density residential zoning 2. Large single-residence lots TsunamiTsunami RiskRisk ReductionReduction
3.3. Locate and configure new development in the run-up areas to minimize future tsunami losses
¾ Avoid inundation areas
SLOWING i.e. build on high ground ¾ Slowing water currents i.e. Conserve or replant coastal belts of forest and mangrove swamps ¾ Steering water forces STEERING i.e. angled, by-pass walls ¾ Blocking water forces i.e. Build sea walls
BLOCKING Source: National Tsunami Hazard Mitigation Program (NTHMP) TsunamiTsunami RiskRisk ReductionReduction
4.4. Design and construct new buildings to minimize tsunami damage
¾ Heavy and rigid structure
¾ Raise building on stilts*
¾ Many openings on the ground floor *
¾ Orient perpendicular to the shoreline:
Elevated restaurant in Hilo, Hawaii. Lower level is designed to allow waves to pass through. *Use caution with this design in areas Source: National Tsunami Hazard Mitigation Program with high earthquake-shaking risk. TsunamiTsunami RiskRisk ReductionReduction 4. Tsunami-resistant buildings (cont.)
Overturning
Sliding Tsunami forces on structures WAVE Scouring
Water pressure & debris impact Buoyancy Rigid connection
Lowest Horizontal horizontal member structure perpendicular to above wave- the wave crest Structure designed to resist Lateral bracing tsunami forces
Deep protected piles
Source: National Tsunami Hazard Mitigation Program (NTHMP) Caveat:Caveat: RememberRemember EarthquakeEarthquake-- ResistantResistant DesignDesign PrinciplesPrinciples
¾ Most communities at risk from tsunamis are also at risk from damaging earthquakes ¾ Buildings designed well for earthquakes typically perform well in tsunamis
Photo: Jose Borrero Photo: Jose Borrero Well-designed building standing amidst the Well-designed building withstood tsunami forces rubble in Banda Aceh, Indonesia without collapse in Banda Aceh, Indonesia TsunamiTsunami RiskRisk ReductionReduction
5.5. Protect existing development through redevelopment, retrofit, and land reuse plans and projects
6.6. Take special precautions in locating and designing infrastructure and critical facilities ¾ Locate critical infrastructure (water plants, hospitals, etc) outside the tsunami danger zone ¾ Relocate or protect critical infrastructure ¾ Plan for emergency and recovery TsunamiTsunami RiskRisk ReductionReduction
¾¾ Plan for Evacuation ¾ Identify vertical evacuation buildings ¾ Create horizontal evacuation routes ¾ Develop early warning systems ¾ Educate and inform public TsunamiTsunami RiskRisk ReductionReduction 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. TsunamiTsunami RiskRisk ReductionReduction
The least expensive and the most important mitigation effort is …
"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 TheThe powerpower ofof knowledge:knowledge:
¾ Victor Desosa saved the village of Galbokka in Sri Lanka because he knew what to do when the water receded. ¾ Only one inhabitant in his village was killed. ¾ Casualty rates in nearby villages were 70 – 90 % “Natural“Natural hazardshazards areare inevitable.inevitable. NaturalNatural disastersdisasters areare not.”not.”
John Filson, USGS retired New York Times December 27, 2004 EarthquakeEarthquake EngineeringEngineering ResearchResearch InstituteInstitute
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To contact us or become a member of EERI, visit our website: www.eeri.orgwww.eeri.org ReferencesReferences ¾ United States Geological Survey (USGS) ¾ U.S. National Oceanic and Atmospheric Administration (NOAA) ¾ UNESCO / Intergovernmental Oceanographic Commission (IOC) ¾ International Tsunami Information Center (ITIC) ¾ Laboratoire de Geophysique, France (LDG) ¾ Earthquakes: A Primer, Bruce A . Bolt, W.H. Freeman, 1978 ¾ Digital Globe ¾ Geological Survey of India ¾ National University of Singapore ¾ New Scientist magazine, Issue #2482, January 15, 2005 ¾ BBC News ¾ Nature, Vol. 433, January 27, 2005, Nature Publishing Group ¾ Sri Lanka Reconnaissance Teams: http://walrus.wr.usgs.gov/tsunami/srilanka05/ & http://www.gtsav.gatech.edu/cee/groups/tsunami/index.html ReferencesReferences (cont.) ¾ Natural Tsunami Hazard Mitigation Program (NTHMP), Designing for Tsunamis, March 2001 ¾ National Information Service for Earthquake Engineering (NISEE), Earthquake Image Database, Karl Steinbrugge Collection ¾ www.wavesofdestruction.org ¾ “Field Survey of Northern Sumatra,” Jose Borrero, EERI Newsletter, March 2005 ¾ Pacific Tsunami Museum ¾ NOVA: “The Wave that Shook the World,” PBS http://www.pbs.org/wgbh/nova/tsunami/ ¾ Metro TV, Surabaya Citra Televisi Indonesia (SCTV), Rajawali Citra Televisi Indonesia (RCTI) ¾ Prof. Wiratman Wangsadinata, Wiratman & Associates Consulting Company, Indonesia ¾ EERI’s Virtual Clearinghouse: http://www.eeri.org/lfe/clearinghouse/sumatra_tsunami/overview.html