M8.6 EARTHQUAKE STRIKES OFFSHORE BANDA ACHE,

INDONESIA: WED. AM, APRIL 11, 2012

Walter Hays, Global Alliance for Disaster Reduction, University of

North Carolina, USA

WITH A TSUNAMI WANING IN EFFECT, AREA RESIDENTS

FEARED A REPEAT OF DECEMBER 26, 2004

Remembering December 26, 2004, residents began

evacuating immediately

WARNING THE PEOPLE IN BANDA ACHE

MASS EVACUATION BEGAN IMMEDIATELY IN BANDA ACHE

MASS EVACUATION BEGAN IMMEDIATELY IN BANDA ACHE

--- AND IN SRI LANKA

The good news: The tsunami wave runup was

only 1 meter (3.3 ft) and only 5 deaths, at present.

WHY WAS THE TSUNAMI SO WEAK? (Source: USGS)

• The April 11th earthquake, unlike the December, 2004 earthquake, occurred 150 km from the sub-duction zone.

• In addition, the fault rupture was mainly strike-slip; NOT thrust; hence the April 11th quake was not effective as a tsunami generator.

TO EVACUATE OR NOT TO EVACUATE FOR TSUNAMIS

A PRIMER

NATURAL HAZARDS FOR WHICH NATURAL HAZARDS FOR WHICH EVACUATION IS TYPICALEVACUATION IS TYPICAL

NATURAL HAZARDS FOR WHICH NATURAL HAZARDS FOR WHICH EVACUATION IS TYPICALEVACUATION IS TYPICAL

FLOODS

HURRICANES

TYPHOONS

TSUNAMIS

VOLCANIC ERUPTIONS

WILDFIRES

HIGH BENEFIT/COST FOR SAVING LIVES, BUT LOW BEMEFIT/COST FOR PROTECTING PROPERTY

HIGH BENEFIT/COST FOR SAVING LIVES, BUT LOW BEMEFIT/COST FOR PROTECTING PROPERTY

GOAL: MOVE PEOPLE OUT GOAL: MOVE PEOPLE OUT OF HARM’S WAYOF HARM’S WAY

GOAL: MOVE PEOPLE OUT GOAL: MOVE PEOPLE OUT OF HARM’S WAYOF HARM’S WAY

Natural Phenomena that can Cause Disasters

Planet Earth’s Restlessness causes:

Earthquakes

Tsunamis Are Associated with Subduction Zone Earthquakes

• M 7 or larger earthquakes that occur in oceanic subduction zones cause:

Tsunamis

SUBDUCTION ZONE SUBDUCTION ZONE

A TSUNAMI WAVE CAN REACH 10 M OR MORE IN HEIGHT

A TSUNAMI WAVE CAN REACH 10 M OR MORE IN HEIGHT

COMMUNITYCOMMUNITYCOMMUNITYCOMMUNITYDATA BASES DATA BASES AND INFORMATIONAND INFORMATIONDATA BASES DATA BASES AND INFORMATIONAND INFORMATION

HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS

•TSUNAMI HAZARDS •INVENTORY•VULNERABILITY•LOCATION

RISK ASSESSMENTRISK ASSESSMENT

RISK

ACCEPTABLE RISK

UNACCEPTABLE RISK

TSUNAMI DISASTER RISK TSUNAMI DISASTER RISK REDUCTIONREDUCTION

•PREVENTION/MITIGATION•PREPAREDNESS•EMERGENCY RESPONSE•RECOVERY and RECONSTRUCTION•EDUCATIONAL SURGE

POLICY OPTIONSPOLICY OPTIONS

TSUNAMI HAZARDS (AKA POTENTIAL DISASTER AGENTS)

• HIGH-VELOCITY, LONG-PERIOD WATER WAVES

• WAVE RUNUP • FLOODING• WAVE RETREAT• SHORELINE EROSION

HIGH VELOCITY IMPACT OF INCOMING WAVES

TSUNAMIS TSUNAMIS

INLAND DISTANCE OF WAVE RUNUP

VERTICAL HEIGHT OF WAVE RUNUP

INADEQUATE RESISTANCE OF BUILDINGS

FLOODING

INADEQUATE HORIZONTAL AND VERTICAL EVACUATION

PROXIMITY TO SOURCE OF TSUNAMI

CAUSES OF DAMAGE

CAUSES OF DAMAGE

“DISASTER LABORATORIES”

“DISASTER LABORATORIES”

MONITORING TECHNOLOGIES AND WARNING SYSTEMS ARE A VITAL PART OF THE STORY.

KNOWING WHERE, WHEN, AND WHY A TSUNAMI OCCURS IS A VITAL PART OF THE ART

AND SCIENCE OF INTELLIGENT EVACUATION.

INTELLIGENT EVACUATION:LEAVE THE AREA OR EVACUATE VERTICALLY

INTELLIGENT EVACUATION:LEAVE THE AREA OR EVACUATE VERTICALLY

• LEAVE, IF ENOUGH ADVANCE WARNING

• EVACUATE TO A TALL BUILDING OR A HIGHER ELEVATION TO GET BEYOND REACH OF THE TSUNAMI’S WAVE RUNUP.

• LEAVE, IF ENOUGH ADVANCE WARNING

• EVACUATE TO A TALL BUILDING OR A HIGHER ELEVATION TO GET BEYOND REACH OF THE TSUNAMI’S WAVE RUNUP.

THE ART AND SCIENCE OF KNOWING WHEN TO EVACUATE

BEFORE A TSUNAMI WAVE ARRIVES AND WHERE TO GO

CAN BE THE DIFFERENCE BETWEEN LIFE AND DEATH.

EVACUATION FOR A TSUNAMI IS COMPLICATED BY:

1) THE SHORT TIME BETWEEN THE EARTHQUAKE AND THE TSUNAMI

WAVE ARRIVAL, AND

2) DAMAGE AND LOSS OF FUNCTION TO BUILDINGS AND INFRASTRUCTURE CAUSED BY THE EARTHQUAKE AND

ITS AFTER SHOCK SEQUENCE.

WHEN YOU CHOOSE NOT TO EVACUATE, OR YOU ARE

UNABLE TO EVACUATE, THE ODDS FOR SURVIVAL ARE

LOWER, BECAUSE ---

YOU CAN’T OUTRUN OR DIVERT10-M-HIGH, DEBRIS-LADEN,

OCEAN WAVES THAT ARRIVE WITH A HIGH VELOCITY (E.G., 30 TO 300 KM/HR) AND MOVE

RAPIDLY INLAND FOR 2-3 KM, OR MORE

DETAILS OF THE STORY

EXAMPLE 1: GREAT SUMATRA EARTHQUAKE-INDIAN OCEAN

TSUNAMI DISASTER

DECEMBER 26, 2004

(A Sunday morning)

ABOUT ½ HOUR FOR TSUNAMI WAVES TO REACH BANDA ACHE; LONGER FOR OTHER

LOCATIONS

TSUNAMI TRAVERSES INDIAN OCEANI: 26 DECEMBER 2004

THE FACTS

• THE TSUNAMI WAS GENERATED BY A SHALLOW, M 9.3 EARTHQUAKE LOCATED 260 KM (155 MI) FROM BANDA ACEH, SUMATRA

THE FACTS

• THE TSUNAMI WAVES HAD HEIGHTS OF 4 TO 10 M AND RUNUP OF 3.3 KM OR MORE ON THE COAST LINES OF 12 NATIONS

THE FACTS

• THE EXISTING TSUNAMI WARNING SYSTEM WAS INEFFECTIVE.

• LITTLE OR NO EVACUATION.

THE FACTS (Continued)

• AN ESTIMATED 220,000 PEOPLE WERE KILLED (120,000 IN INDONESIA) AND 500,000 INJURED IN 12 COUNTRIES BORDERING THE INDIAN OCEAN

THE FACTS (Continued)

• THE MOST URGENT IMMEDIATE NEED WAS FOR FOOD, WATER, AND HEALTH CARE SERVICES.

• DISEASES APPROACHING AN EPIDEMIC, “A DISASTER AFTER THE DISASTER,” DID NOT HAPPEN.

BEFORE DECEMBER 26, 2004 EARTHQUAKE-TSUNAMI

AFTER DECEMBER 26, 2004 EARTHQUAKE-TSUNAMI

BEFORE DECEMBER 26, 2004 EARTHQUAKE-TSUNAMI

AFTER DECEMBER 26, 2004 EARTHQUAKE-TSUNAMI

IMPACTS OF TSUNAMI DISASTER

• MILLIONS DISPLACED AND HOMELESS

• LOSSES IN $ BILLIONS

• INTERNATIONAL DONORS CONTRIBUTED OVER $ 1 BILLION IN EFFORT COORDINATED BY THE UN, USA, INDIA, AUSTRALIA, & JAPAN.

INTERNATIONAL DONORS RESPOND

• INTERNATIONAL DONORS CONTRIBUTED OVER $ 1 BILLION IN EFFORT COORDINATED BY THE UN, USA, INDIA, AUSTRALIA, & JAPAN.

TSUNAMI WARNING SYSTEM FOR INDIAN OCEAN REGION

• UNESCO, IN COOPERATION WITH OTHER ORGANIZTIONS, TOOK THE LEAD FOR DEVELOPING AND IMPLEMENTING AN INPROVED TSUNAMI WARNING SYSTEM FOR THE INDIAN OCEAN.