Tom Wilson Lecturer in Hazard and Disaster Management Dept of Geological Sciences University of Canterbury Acknowledgements : David Bell (UC), Jarg Pettinga (UC), Mark Quigley (UC), Graham Leonard (GNS Science), William Power (GNS Science) Overview of Seminar New Zealand: our world class natural hazards laboratory Active geological landscape EQ, Volcanic, Tsunami, What information is GeoScience aiming to produce Lessons from the Canterbury Earthquake Sequence Success and limitations of geoscience Geoscience and Emergency Management What can be expected... What we expect from you... 1: New Zealand’s active geological landscape Plate tectonics… What happens at plate boundaries? New Zealand tectonics and Geology New Zealand is the ‘ideal’ natural hazards laboratory! “It does us a power of good to remind ourselves that we live on two volcanic rocks where two tectonic plates meet, in a somewhat lonely stretch of windswept ocean just above the Roaring Forties. If you want drama - you've come to the right place“ Former Prime Minister Sir Geoffrey Palmer Define each of these: What is a Hazard? What is Vulnerability? What is Risk? What are Geoscientists worried about? Geohazards: • Magnitude – how big is the event(s) going to be in space and time? • Frequency – when is the next event(s) going to occur? (tied to probability) • Ensuring the scientific data is used appropriately and effectively - Market base approach (value for money) - Return on investment • Geological disasters appear to be increasing...! • Who is exposed and how vulnerable are they Some of challenges... • Geological systems are complex and operate in 4-dimensions • 4D system but often can only see 2D • Geological timescales are very different to human timescales • Preservation potential • Geological disasters are commonly “surprising” – “didn’t fit the model” • Severe, complex, cascading implications... • In the context of a society looking to manage risk, society is demanding that geological risk be better managed • So...looking at ourselves – what can we do better? • Risk Assessment: Increased societal demand, understanding and access to technology has driven an increasing quantification of geological risk • Use of Geological Risk information: our job doesn’t stop once we’ve produced the data EARTHQUAKES BODY WAVES (P & S) P = primary (compressional) S = secondary (transverse) In rock P>6km/sec & S ≈50% of P SURFACE WAVES Include Rayleigh & Love waves Travel at surface & not through rock and thus slower Can cause major damage to buildings & infrastructure Effects of Earthquakes TERRAIN Ground warping &/or rupture offset (≤10m) Triggering of landslides, rockfalls & liquefaction WATER Well level changes & seiche effects in lakes Generation of tsunami waves (eg Boxing Day 2005) STRUCTURES Structural damage (depends on design & age etc) Failure of “lifelines” due to shaking or offset PEOPLE Loss of life or injury from building collapse etc Social disruption from loss of services Psychosocial effects Earthquakes in NZ Source: Barnes et al. (2011) Earthquake Probability of Occurrence Using seismology and geology 5 Years 15 Years Probabilistic Seismic Hazard Analysis (PSHA) Peak ground acceleration (-g) expected at 10% probability in 50 years (g) 100 Years From: Stirling, M.; Gerstenberger, M.; Litchfield, N.; McVerry, G.; Smith, W.; Pettinga, J.; Barnes, P. (2008): Updated probabilistic seismic hazard assessment for the Canterbury Region. Volcanic Hazards Examples of volcanic hazards: lava flows lava domes pyroclastic falls (ash fall) and pyroclastic flows lahars and debris avalanches volcanic gases The volcano problem... Range of hazards Range of volcano types Range of different eruption magnitudes from one volcano Range of different hazards produced within an eruption Taupo 22.5 kyr Eruption Sizes ( a range) Probabilistic ash fall map for central North Island for multiple volcanic sources (excludes Auckland) Hurst and Smith (2004) Tsunami For effective management we need to know: • What sources affect NZ? Geology, seismology • How big and how often? Seismology • How high will the waves be? Math. Modelling • What are the run-up consequences? Engineering There is a level of understanding of all of these, but uncertainties are still large. Geological investigations and historical studies provide checks on all of these. Then we can evaluate how often for any given wave height Distant tsunami sources for Napier: Location and magnitude - the principal factors that determine impact in NZ Estimated Maximum water level at Napier for Mw 9.0, by source location Modelling by William Power (GNS Science) using NOAA (PMEL) MOST programs. G Leonard slide (GNS Science) . Local sources – Hikurangi plate interface Many unknowns, many possible scenarios with variations in • fault length • distributed movement along and up the fault • • • • fault rupture terminates at shallow depth fault ruptures to surface along one or more splay faults fault ruptures to surface along the plate interface hybrid of these Effect of various rupture scenarios on vertical seafloor displacement (and hence the tsunami generation capacity) Geist (2005) Local earthquake sources – Hikurangi Margin plate interface Slip distribution (per 100 years of released slip deficit) Press to play Tsunami modelling by William Power (GNS Science) in 2006 based on Wallace et al (2004 ) geodetic model of plate locking beneath Wellington/Wairarapa. Power et al. EQC funded Project 2006/521 This is just one scenario: rupture up splay faults releasing 400 years of plate interface locking in a very large earthquake (over magnitude 8). Global Disaster Trends 2010 + 2011??? Physical Systems HAZARDS + DISASTERS Human Systems The Canterbury Earthquake Sequence... It’s rattled more than just the pot-plants Isn’t New Zealand highly motivated at promoting earthquake resilience? Why did so many people build on liquefiable land? Aren’t our buildings meant to stay standing during earthquakes? I thought EQC had HEAPS of money for disasters? And now what happens now with Wellington? Consequences – the numbers 10,000’s homes damaged and >1,100 buildings demolished Reduced habitability and strained city’s ability to accommodate it’s residents 7,500 residential properties retired: ~5% of total housing stock Central Business District closed for months New Zealand’s largest short-term migration 70,000 people evacuated: 19% of population 3,000 long term migration: <1% of population 8 millions tonnes of disaster waste: 40 years of Chch waste Total damage: estimated at >$20 billion (>10% GDP) EQC reserved exhausted and central government very tight (GFC) One of the greatest geotechnical disasters of the modern age Lessons from the Canterbury Earthquake Sequence Success and limitations of geoscience... What can we unpack from this? Very difficult situation Sustained earthquake sequence in a previously seismically ‘quiet’ region Unmapped faults Sequence has migrated across an major urban area Most damaging EQ since the 1931 Napier earthquake Seismicity for August 2010 To this… No systematic increase in earthquake rate or magnitude prior to Sept 4 2010 Aftershocks Seismicity……..How many so far? Numbers of Earthquakes in the Canterbury Region since 4 September 2010 Magnitude range Number 7.0 and above 1 6.0 - 6.9 3 5.0 - 5.9 55 4.0 - 4.9 423 (+1 to June 24) 3.0 - 3.9 3143 (3024 on 31 May 2012) This table was last updated on 19 June 2012 Source: www.Geonet.org.nz Total now well over 10,000 recorded events B Duffy using Geonet data Aftershock Decay Sequence for Canterbury (X10) - Magnitude 3 and greater Dec 23/11 M6.0 June 13/11 M6.3 Feb 22/11 M6.3 Source: www.geonet.org.nz Sept 4/10 M7.1 Graph depicts the significant effect of the February, June and December 2011 earthquakes reenergising the Darfield aftershock sequence (Source: GNS Science). Successes High quality seismological dataset Informed detailed forecasts and crustal strain models Significant input to geotechnical hazard and risk analysis & planning liquefaction studies and rockfall/slope stability) Helped explain the phenomena to emergency management and a “highly unsettled” public Hazard assessment worked. Correctly identified: Chch was exposed to seismic hazards Major potential for liquefaction Surprises Earthquakes on unmapped faults Long duration of aftershock sequence, migrating across the city High ground shaking experienced in Chch city Cliff collapse – Port Hills Transparency of analysis & decision making processes This is not a blame game – it is about learning lessons for the future Limitations Forecasting locating, timing and magnitude of earthquakes – even after the sequence began We can’t predict earthquakes We can’t communicate our forecasts Hazard assessment was successful...but... Liquefaction and “blind” faults in Canterbury Why wasn’t this information better used? Our probabilistic analysis needed slight revision “Floating” statistical earthquake This is not a blame game – it is about learning lessons for the future Prediction vs. Forecasting Prediction Requires: A time interval during which the earthquake is predicted (short-term = hours to months, medium term = years to decades, long-term = decades to centuries) An area within which the earthquake is predicted, A depth range for the earthquake, A range of magnitudes within which the earthquake is predicted to occur, And, very importantly, The probability that the earthquake will fall within all these intervals, as measured by past successes and failures of the predictive method. Unless all these requirements are met, the “prediction” cannot be tested against the occurrence or non-occurrence of the earthquake, and therefore the “prediction” is valueless Mark Quigley & Jarg Pettinga - 2012 Probabilistic Forecasting Earthquakes: • Short-term forecasting makes use of aftershock models • Medium and long-term forecasting from geology, GPS and seismicity modeling Without Aftershocks: Earthquake Sources in 3D Background (Point) Sources • Constructing a seismic hazard model • Requires geological investigations Seismological vs Geological Fault Sources Earthquake Hypocentres Magnitude - Frequency Distributions Background n/yr M + Fault = Combined Forecasting Earthquake Activity in Canterbury • Short Term (hours to months) • Medium Term (years) • Long Term (decades) Source: “Geonet” Aftershock Forecasting Canterbury region extended probabilities: Short-Term Medium-Term One month: 28 May – 27 June ‘12 One year: 28 May ‘12 – 27 May ‘13 Magnitude range Expected range Expected average Probability Expected range Expected average Probability 5.0 - 5.4 0-1 0.19 17% 0-4 1.4 75% 5.5 - 5.9 0-1 0.05 5% 0-2 0.4 33% 6.0 - 6.4 0-1 0.014 1% 0-1 0.1 10% 6.5 - 6.9 0-1 0.004 <1% 0-1 0.03 3% 7.0 - 7.9 0-1 0.0015 <1% 0-1 0.01 1% This table was last updated on 28 May 2012 Source: www.geonet.org.nz Chch EQ Hazard Assessment Fault sources which might affect Chch had been well identified Difficult to deal with blind (unmapped) sources...but: They had been theorised Some even identified Hindsight is a...wonderful thing We’ve known about Christchurch’s liquefaction hazard for a long time (map compilation - 2005) http://ecan.govt.nz/publications/General/solidfacts-christchurch-liquefaction.pdf Feb 2011 Liquefaction From Tonkin + Taylor with contributions from many Unprecedented level of liquefaction across an urban 3: Geoscience & Emergency Management Some reflections from the past 18 months: Most of us (geoscientists) have no idea how you operate What is your role? What do you do? What language do you speak? CIMS... Isn’t that a computer game...? Research timescales vs operational demands... Geoscience research paper: 2-5 years: start to finish Communication... Communicating the right information in the right form to the right people • Two ways to look at it: • Politicians, emergency managers and the general public do not understand uncertainty... • Scientists do not communicate uncertainty well... • Successes (apparent or real) create the expectation that geoscientists will get it correct, every time. • Reality is that geologic hazard and risk assessment is fraught with uncertainty... • This MUST be adequately communicated: UNDERSTAND your audience Minimise JARGON The audience is SMART, it’s just that they aren’t an expert like you TRUST is easy to lose and hard to win back Integration of researchers with emergency management “Science” (in broad terms) produces a product which is fundamental for emergency managers WHAT HAPPENED??!! - Geotechnical + seismological Emerging risks (first-order geological and second-order sociological) Challenges for researchers • Who did the research serve? • • • Operational emergency management demands? Or more lofty research goals? Who decides? In the absence of a plan, it was often up to the individual researcher 4 Sept 2010 was a practise run for 22 Feb 2011 event. Did we learn our lessons...??? Challenges for the researchers • Who did the research serve? • Information needs were/are complex and usually transcend disciplines Requires excellent coordination and leadership between researchers and research teams, and with stakeholders • • • • • • Dynamic, tiring, conflicting, confusing conditions High profile...which is a double edged sword... Simple, binary answers are required by stakeholders and the public... But this is not how scientists are trained to communicate... Physical scientists and engineers have had to learn about the ethics committee Integration of researchers with emergency management Inclusion of researchers with “recovery groups” seemed to be mostly positive Yet it didn’t happen in many cases (no pre-existing relationship) Research benefits Increased situational awareness = could begin to anticipate information needs... Will inform the current and future research (this disaster, and the next...) • Operational benefits Had their own personal scientist Often researchers had greater access to information and resources Researchers have significant capability to offer A potential solution? Sarah Beaven (UC) The desired state: improve trust and collaboration between researchers and emergency management familiarize researchers with emergency management processes and requirements demystify (and validate the value of) research and science for emergency managers and vice-versa Earthquake response indicates value of: Continuing to develop the Natural Hazards Platform into a more networked, transparent open structure, grounded in public domain • Better integration with the CDEM model, using detailed strategies and guidelines for research collaboration at all levels, providing for: o Regular and specific training requirements with emergency services o Protocols and procedures during emergencies o Relevant local/regional organizations to initiate (& coordinate in collaboration with GNS & others) research responses to events occurring in their region - reliance on local research expertise in first few days • Potential to increase national research and emergency management networking, and so adaptive capacity Recap Geohazards driven by planetary scale forces (plate tectonics) Hazards occur at a variety of scales in time and space New Zealand is located at an active plate margin We will have more disasters Lessons from Canterbury... difficult and limiations on geoscience Expectations of Geoscience and from Geoscience need to be known, established, dyanmic, transparent and well-practised!