Transcript earthquakes
LESSONS LEARNED FROM PAST NOTABLE DISASTERS NEW ZEALAND PART 3A: EARTHQUAKES Walter Hays, Global Alliance for Disaster Reduction, Vienna, Virginia, USA Natural Phenomena that Cause Disasters Planet Earth’s Restlessness Causes Movement of Tectonic Plates: Earthquakes NATURAL HAZARDS THAT HAVE CAUSED DISASTERS IN NEW ZEALAND FLOODS GOAL: PROTECT PEOPLE AND COMMUNITIES HIGH BENEFIT/COST PROGRAMS FOR BECOMING DISASTER RESILIENT WINDSTORMS EARTHQUAKES VOLCANOES ENVIRONMENTAL CHANGE GLOBAL CLIMATE CHANGE TECTONIC PLATES New Zealand is in the southwest Pacific Ocean astride the “ring of fire,” a distinct belt of volcanic and earthquake activity that surrounds the Pacific Ocean SUBDUCTION OCCURS BENEATH THE NORTH ISLAND To the north of New Zealand and beneath the eastern North Island, the thin, dense, Pacific plate moves down beneath the thicker, lighter Indo-Australian plate in a process known as subduction (i.e., reverse faulting). Within the South Island the plate margin is marked by the Alpine Fault and the plates rub past each other horizontally (i.e., strike-slip) NEW ZEALAND’S SUBDUCTION ZONE AND ALPINE FAULT About 20,000 earthquakes (most, but not all are small) are recorded in New Zealand every year as a result of its location in the Pacific Ring of Fire SEISMICITY MAP: VICINITY OF CHRISTCHURCH ELEMENTS OF RISK AND DISASTER ELEMENTS OF EARTHQUAKE RISK HAZARDS EXPOSURE RISK VULNERABILITY LOCATION A DISASTER CAN HAPPEN WHEN THE POTENTIAL DISASTER AGENTS OF AN EARTHQUAKE INTERACT WITH THE VULNERABLE BUILT ENVIRONMENTS OF NEW ZEALAND’S COMMUNITIES EARTHQUAKE HAZARDS: ARE POTENTIAL DISASTER AGENTS FAULT RUPTURE DAMAGE/LOSS EARTHQUAKE GROUND SHAKING DAMAGE/LOSS TSUNAMI DAMAGE/ LOSS TECTONIC DEFORMATION DAMAGE/ LOSS FOUNDATION FAILURE DAMAGE/ LOSS SITE AMPLIFICATION DAMAGE/ LOSS LIQUEFACTION DAMAGE/ LOSS LANDSLIDES DAMAGE/ LOSS AFTERSHOCKS DAMAGE/ LOSS SEICHE DAMAGE/ LOSS GROUND SHAKING PROBABILISTIC GROUND SHAKING MAP (CHRISTCHURCH IN YELLOW) NEW ZEALAND’S CITIES The largest cities within this high risk zone are the nation's capital, Wellington, followed by Hastings then Napier; all of them have experienced damaging earthquakes. NOTE: The central part of most cities is comprised mainly of old, vulnerable brick and unreinforced masonry buildings, which are highly susceptible to damage. CONSTRUCTION MATERIALS HAVE DIFFERENT VULNERABILITIES TO GROUND SHAKING MEAN DAMAGE RATIO, % OF REPLACEMENT VALUE 35 30 25 20 15 10 5 0 V VI VII INTENSITY VIII IX CAUSES OF DAMAGE INADEQUATE RESISTANCE TO HORIZONTAL GROUND SHAKING SOIL AMPLIFICATION PERMANENT DISPLACEMENT (SURFACE FAULTING & GROUND FAILURE) EARTHQUAKES IRREGULARITIES IN ELEVATION AND PLAN “DISASTER LABORATORIES” FIRE FOLLOWING RUPTURE OF UTILITIES LACK OF DETAILING AND CONSTRUCTION MATERIALS INATTENTION TO NONSTRUCTURAL ELEMENTS A DISASTER is ----- the set of failures that overwhelm the capability of a community to respond without external help when three continuums: 1) people, 2) community (i.e., a set of habitats, livelihoods, and social constructs), and 3) complex events (e.g., earthquakes, landslides,..) intersect at a point in space and time. Disasters are caused by single- or multiple-event natural hazards that, (for various reasons), cause extreme levels of mortality, morbidity, homelessness, joblessness, economic losses, or environmental impacts. THE REASONS ARE . . . • When it does happen, the functions of the community’s buildings and infrastructure will be LOST because they are UNPROTECTED with the appropriate codes and standards. THE REASONS ARE . . . • The community is UNPREPARED for what will likely happen, not to mention the low-probability of occurrence— high-probability of adverse consequences event. THE REASONS ARE . . . • The community has NO DISASTER PLANNING SCENARIO or WARNING SYSTEM in place as a strategic framework for concerted local, national, regional, and international countermeasures. THE REASONS ARE . . . • The community LACKS THE CAPACITY TO RESPOND in a timely manner to the full spectrum of expected and unexpected emergency situations. THE REASONS ARE . . . • The community is INEFFICIENT during recovery and reconstruction because it HAS NOT LEARNED from either the current experience or the cumulative prior experiences. THE ALTERNATIVE TO DISASTER: EARTHQUAKE DISASTER RESILIENCE EARTHQUAKE RISK • QUAKE HAZARDS •INVENTORY •VULNERABILITY •LOCATION DATA BASES AND INFORMATION ACCEPTABLE RISK RISK UNACCEPTABLE RISK NEW ZEALAND’S COMMUNITIES QUAKE DISASTER RESILIENCE POLICY OPTIONS HAZARDS: GROUND SHAKING GROUND FAILURE SURFACE FAULTING TECTONIC DEFORMATION TSUNAMI RUN UP AFTERSHOCKS •PREPAREDNESS •PROTECTION •FORECASTS/SCENARIOS •EMERGENCY RESPONSE •RECOVERY and RECONSTRUCTION LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL EARTHQUAKES PREPAREDNESS FOR THE LIKELY GROUND SHAKING AND GROUND FAILURE IS ESSENTIAL FOR DISASTER RESILIENCE LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL EARTHQUAKES BUILDING CODES AND LIFELINE STANDARDS ARE ESSENTIAL FOR DISASTER RESILIENCE LESSONS LEARNED ABOUT DISASTER RESILIENCE ALL EARTHQUAKES TIMELY EMERGENCY RESPONSE IS ESSENTIAL FOR DISASTER RESILIENCE NEW ZEALAND’S NOTABLE EARTHQUAKES M7.1 : SATURDAY, SEPT. 3, 2010 TWO EARTHQUAKES SEVERELY CUT NEW ZEALAND’S 2011 ECONOMIC GROWTH A DEEP (33 KM) M7.1 AND A SHALLOW (4 KM) M6.3 QUAKE SIX MONTHS APART COMBINE TO HALF NEW ZEALAND’S ECONOMIC GROWTH M7.1 EARTHQUAKE STRIKES NEAR CHRISTCHURCH, NEW ZEALAND A DEEP (33 KM) QUAKE LOCATED 50 KM FROM CHRISTCHURCH STRUCK AT 4:35 AM SEPTEMBER 3, 2010 EPICENTER: NEAR CHRISTCHURCH, NEW ZEALAND In Christchurch, a city of 372,000, power and water services were knocked out, facades fell off buildings, homes businesses, and bridges were damaged by strong shaking, fires were ignited, and the Christchurch Airport was closed. IMPACTS Numerous injuries, but no deaths, largely due to the 4:35 a.m. time of occurrence, NOT BECAUSE the buildings were resilient to the strong ground shaking DAMAGE: BFORE (TOP) AND AFTER (BOTTOM) TYPICAL DAMAGE: UNREINFORCED MASONRY BUILDINGS DAMAGE: CHRISTCHURCH DAMAGE TO CARS DAMAGE: CHRISTCHURCH POUNDING FIRE DAMAGE: CHRISTCHURCH DAMAGE: CHRISTCHURCH DAMAGE: MOTORWAY LOCAL GROUND FAILURE AFTERSHOCKS OF THE 3 SEPT 2010 QUAKE • Christchurch was hit by hundreds of aftershocks after the M7.1 earthquake of 3 September 2010, which exacerbated damage and added new injuries, but no new deaths. THE TOLL: EXTENSIVE DAMAGE, BUT NO DEATHS • The earthquake (and its aftershocks) caused extensive damage to buildings and infrastructure, but no deaths. ECONOMIC LOSS: ESTIMATED AT $1.5 billion. NEW ZEALAND’S NEXT DAMAGING EARTHQUAKE WAS INEVITABLE • ---BUT, THE NEW ZEALANDERS DIDN’T EXPECT IT SO SOON--FEB. 21, 2011, A SECOND REMINDER OF THE IMPORTANCE OF EARTHQUAKE DISASTER RESILIENCE.