Risk on the Rise: Understanding and Managing Coastal Flood Risk
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Coastal areas are some of the most developed or developing environments across the globe. These regions contain significant accumulations of exposure and are vulnerable to substantial flood hazard. A comprehensive understanding of those exposures, and the complex hazards that can impact them, is imperative to better manage your flood business. In this webinar, RMS' Dr. Robert Muir-Wood and Juergen Grieser take an in-depth look at coastal flood risk.
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Risk on the Rise: Understanding and Managing Coastal Flood Risk
- 1. 1Copyright © 2015 Risk Management Solutions, Inc. All Rights Reserved. October 13, 2015 RISK ON THE RISE UNDERSTANDING AND MANAGING COASTAL FLOOD RISK Robert Muir-Wood and Juergen Grieser 1Copyright © 2015 Risk Management Solutions, Inc. All Rights Reserved. October 13, 2015
- 2. 2 MEET THE EXPERTS Robert Muir-Wood, Ph.D. Chief Research Officer Juergen Grieser, Ph.D. Director, Model Development
- 3. 333 BOUNDARY IS THE RISK CONCENTRATORS WHY THE LAND-SEA BIGGEST OF ALL
- 4. 4 EVENTS WHERE MORE THAN 50% OF THE LOSS WAS COASTAL Thai Floods Superstorm Sandy Tohoku EQ and Tsunami Hurricane Katrina
- 5. 5Copyright © 2015 Risk Management Solutions, Inc. HOW LAND VALUES INCREASE AT THE COAST The amenity value of the same property increases significantly at the coast. The most expensive property is then also the most vulnerable. http://www.gradschool.psu.edu/diversity/mcnair/papers2003/majorpdf/ Data from Stone Harbor and Avalon, New Jersey, 2002/2003Photos courtesy of Airbnb.com 3 2.5 2 1.5 1 0.5 0 > 2 Blocks Back 2 Blocks Back Bayfront OceanfrontBeach Block Multipleforresidentialproperty
- 6. 6 COAST-SPECIFIC EXPOSURE CATEGORIES Hotels and condosAirports Ports Marinas Refineries Power plants
- 7. 7Copyright © 2015 Risk Management Solutions, Inc. THE PDF OF GLOBAL EXPOSURE VALUE BY ELEVATION (ABOVE HIGH-WATER LEVEL) For first meter: average value = $1Bn/mm However, pre-existing safety margins give critical thresholding effects. Reconstructed from Anthoff et al., (2006) 1000 750 500 250 0 0 2 4 6 8 10 Meters elevation asl Billions of dollars, U.S.
- 8. 8Copyright © 2015 Risk Management Solutions, Inc. 1000-YEAR WATER HEIGHTS FOR AUSTRALIA ‘Coastal’ should not be measured in ‘distance’ (D2C) but instead in elevation (H2HW). ‘Elevation at risk’ varies by location. ‘Coastal’ is a probabilistic concept.
- 9. 9 BOTH SEA LEVELS AND LAND LEVELS COASTAL RISK IS EXPANDING INLAND ARE CONTINUING TO CHANGE
- 10. 10Copyright © 2015 Risk Management Solutions, Inc. ‘Coastal’ is a probabilistic concept. Many coastal cities are sinking because of urban groundwater extraction.
- 11. 11Copyright © 2015 Risk Management Solutions, Inc. 10-Foot Tsunami SEVERE PHYSICAL DAMAGE POTENTIAL FROM COASTAL FLOOD HAZARDS Damage from a 10-foot storm surge is little different from that of a 10-foot tsunami—note that debris can be a principal driver of severe damage. 10-Foot Storm Surge
- 12. 12Copyright © 2015 Risk Management Solutions, Inc. SEVERE PHYSICAL DAMAGE POTENTIAL FROM COASTAL FLOOD HAZARDS Damage from a 20-foot storm surge is little different from that of a 20-foot tsunami—note that surge will have bigger waves. 20-Foot Storm Surge 20-Foot Tsunami
- 13. 13Copyright © 2015 Risk Management Solutions, Inc. PHYSICAL DAMAGE IS NOT NECESSARILY THE MAIN DRIVER OF LOSS • Spills • Contamination • Loss of production • Local liability (18.5 million people; see report) Meraux Refinery near New Orleans after Hurricane Katrina Photo: FEMA / Patsy Lynch Fukushima Daiichi Plant after Tohoku Japan Earthquake Photo: REUTERS/Ho New
- 14. 14 YOUR FLIGHT HAS BEEN CANCELLED BY HIGH TIDE Bangkok Sendai, 2011 Sandy, La Guardia Grand Bahama x 5 in 15 years
- 15. 151515 COASTAL FLOOD HAZARDS ARE COMPLEX TO MODEL WHAT DOES IT TAKE TO UNDERSTAND TSUNAMI?
- 16. 16 Philippines Sea Plate Eurasian Plate/ Sunda Block Yangtze Plate 90 mm/yr MANILA ARC Ref:Hsu et al. (2012)
- 17. 17 TSUNAMI MODELING COMPONENTS Identify Source Subduction Zones Event Generation Ocean Wave Propagation Coastal Inundation Source Characterization
- 18. 18 WHERE DO WE EXPECT TO SEE COASTAL INUNDATION? Image: S. Astill et al (2013)
- 19. 19 WHERE DO WE EXPECT TO SEE COASTAL INUNDATION?
- 20. 20
- 21. 21 Hong Kong MW9 TSUNAMI FROM THE SOUTHERN LUZON ARC SUBDUCTION ZONE – SOUTHERN CHINA & HONG KONG 0.1 - 1.5 m 1.5 - 3.0 m 3.0 - 4.5 m 4.5 - 6.0 m Industries Tsunami height Source: Esri, DigitalGlobe,DeoEye, I-cubed, Earthstar Geographic, CNES/Airbus DS, USDA, USGS, AEX, Getmapping, Aerogrid, IGN, OISP, swisstopo, and the GIS User Community
- 22. 22 COASTAL FLOOD HAZARDS INNOVATIONS IN MODELING ARE COMPLEX TO MODEL SURGE FLOOD IN JAPAN
- 23. 23Copyright © 2015 Risk Management Solutions, Inc. THERE’S NO SURGE WITHOUT WIND Most of the typhoons hitting Japan have already started transitioning to extratropical storms. Disregarding transitioning can lead to errors in maximum surge height of up to 1.5 m.
- 24. 24Copyright © 2015 Risk Management Solutions, Inc. THERE’S NO SURGE WITHOUT WIND Most of the typhoons hitting Japan have already started transitioning to extratropical storms. Disregarding transitioning can lead to errors in maximum surge height of up to 1.5 m. Reliable wind modeling including extratropical transition is crucial.
- 25. 25Copyright © 2015 Risk Management Solutions, Inc. THERE’S NO SURGE WITHOUT WIND But where is the wind? How strong is it? And in which direction does it blow? Classical typhoon wind footprint Published in Loridan et al. (2014, 2015).
- 26. 26Copyright © 2015 Risk Management Solutions, Inc. THERE’S NO SURGE WITHOUT WIND But where is the wind? How strong is it? And in which direction does it blow? Classical Typhoon wind footprint Transitioning wind footprint Published in Loridan et al. (2014, 2015).
- 27. 27Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST Wind produces currents and waves. Deep Water Shallow Water WindWind
- 28. 28Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST Wind produces currents and waves. The coast produces the surge. Deep Water Shallow Water Low Surge WindWind
- 29. 29Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST Wind produces currents and waves. The coast produces the surge. Deep Water Shallow Water Low Surge High Surge WindWind
- 30. 30Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 31. 31Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 32. 32Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 33. 33Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 34. 34Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 35. 35Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST The Japanese coastline is extremely complex. The coastline can diverge or funnel currents.
- 36. 36Copyright © 2015 Risk Management Solutions, Inc. BATHYMETRY AND THE SHAPE OF THE COAST From a surge perspective, exposure is concentrated at the worst locations. Hiroshima Osaka Nagoya Tokyo
- 37. 37Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 38. 38Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 39. 39Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 40. 40Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 41. 41Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 42. 42Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk.
- 43. 43Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk. Tokyo
- 44. 44Copyright © 2015 Risk Management Solutions, Inc. WHAT IF VERA (1959) HIT SOMEWHERE ELSE? Only detailed hydrodynamic modeling can reveal the risk. Hiroshima Tokyo
- 45. 45Copyright © 2015 Risk Management Solutions, Inc. DEFENCES MAKE THE DIFFERENCE? New Orleans: more than 50 breaches during Hurricane Katrina (2005).
- 46. 46Copyright © 2015 Risk Management Solutions, Inc. DEFENCES MAKE THE DIFFERENCE? • Japan is very well defended. • More than 97% of typhoons hitting Japan do not cause coastal inundation. • This can lead to a wrong feeling of safety. • The probability of a 1000-year surge event happening within the next 50 years is about 5%. WE HAVE TO LIVE WITH THIS RISK
- 47. 47Copyright © 2015 Risk Management Solutions, Inc. DEFENCES MAKE THE DIFFERENCE? Absolutely… …as long as they stand.
- 48. 48Copyright © 2015 Risk Management Solutions, Inc. All Rights Reserved. October 13, 2015 WAVES § Wave modeling is far more complicated than surge modeling § Waves interact with each other in complex ways + =
- 49. 49Copyright © 2015 Risk Management Solutions, Inc. SURGE, TIDES, AND WAVES INTERACT
- 50. 50Copyright © 2015 Risk Management Solutions, Inc. SURGE, TIDES, AND WAVES INTERACT There are many processes, such as: Shoaling, Refraction, Defraction, Reflection...
- 51. 51Copyright © 2015 Risk Management Solutions, Inc. SURGE, TIDES, AND WAVES INTERACT During surge events, higher waves hit the defences.
- 52. 52 DEFENCES MAKE THE DIFFERENCE? Yokohama: breaching increases the losses in this case from 40 million to 17 billion Yen.
- 53. 53 DEFENCES MAKE THE DIFFERENCE? Yokohama, breaching increases the losses in this case from 40 million to 17 billion Yen.
- 54. 54 DEFENCES MAKE THE DIFFERENCE? Yokohama, breaching increases the losses in this case from 40 million to 17 billion Yen.
- 55. 55Copyright © 2015 Risk Management Solutions, Inc. THE IMPLICATIONS OF ‘COASTAL RISK’ • The biggest concentrations of risk and gradients of risk are coastal • Coastal risks vary dramatically with elevation • Always need location/address level data • Need ‘state of the art’ modeling of the hazards – storm surge and tsunami & the defences Under- accelerating sea-level rise defences will not keep pace with the risk until after the disaster.
- 56. 56 RISKS WELL PORTFOLIO WELL AND YOU WILL BE MANAGING YOUR MANAGEYOURCOASTAL
- 57. ©2015 Risk Management Solutions, Inc. RMS and the RMS logo are registered trademarks of Risk Management Solutions, Inc. All other trademarks are property of their respective owners.
Editor's Notes
- https://www.flickr.com/photos/philiproeland/sets/72157628047351910/with/6304842734/
- http://www.ucsusa.org/sites/default/files/attach/2015/02/stormy-seas-rising-risks-ucs-2015.pdf
- http://www.ucsusa.org/sites/default/files/attach/2015/02/stormy-seas-rising-risks-ucs-2015.pdf
- http://www.ucsusa.org/sites/default/files/attach/2015/02/stormy-seas-rising-risks-ucs-2015.pdf
- https://en.wikipedia.org/wiki/Tsunami#/media/File:Hurricane_Ike_Gilchrist_damage.jpg
- So here you can see a schematic of the Manila Arc as we’ve modeled it. The Manila Arc is formed by the subduction of the Eurasian Plate under the Philippine Island Arc. The trench stretches about 900km from southern Taiwan southward to the west coast of Luzon, the largest island of the Philippines and bends a little bit westward, and this is because of the slow westward migration of Luzon over the subducting ocean slab while both ends of the trench are pinned. [Image] It is worthwhile to note that the Manila Trench has not produced a major earthquake for five centuries, at least since the Spanish colonization of Luzon in the mid 1500’s. That means no earthquake greater than 7.8 has been observed on this source – so we can infer that a megathrust event, with some level of confidence, would have a recurrence interval of 500 years or longer. And our calculations put such an event to about 700-1000yrs. According to available geodetic data, the relative motion (convergence rate) across the South China Sea megathrust is somewhere between 5.5cm/yr to 9 cm/yr, with the north of the Manila arc moving at the higher rate, and the south moving at the lower rate. If we do a quick calculation of the strain accumulated over these last 400-500 years, given what we know about the convergence rate of this subduction zone, and the approximate coupling that goes on in this region, we’re looking at strain that comes close to 18m, which if released co-seismically, is similar in scale to the 2010 Maule Chile Event. And there are some researchers out there that put the coupling at even higher rate and the resulting strain closer to 40m, which, if released co-seismically would be similar to the 1960 M9.5 Chile event. That event was catastrophic in the near-field and had major far-field impact in New Zealand, Indonesia, the Philippines and other places across the pacific ocean. So there are different ways of interpreting what could potentially happen at this particular source. In this solution that I’ll show you in a little while, we model about 15m of maximum slip at this source here. Now before we look at more detail of how we are modeling the Manila Arc, it may be worthwhile to put it all into context and look at some of the exposures that could be impacted by this event. <click>
- Identify Sources Eleven historical tsunami events (of local or global significance) were considering in developing this model Two recent earthquakes exceeded the maximum magnitude expected for their respective subduction zones: the 2004 Indian Ocean event on the Sumatra-Andaman subduction zone and the 2011 Tohoku event on the Japan Trench. To account for these types of unanticipated tail events, the seismic hazard community has started to consider the possibility of great earthquakes on various subduction zones. RMS modeled M9 events on various subduction zones around the world where such great earthquakes have not necessarily occurred in the historical past. Source Characterization The tsunami source event characterization model represents an earthquake as a rupture that slips during an earthquake, releasing seismic energy. The model defines the rupture characteristics based on the magnitude of the event and an assumed slip distribution pattern. Event Generation RMS models the seafloor deformation based on the event rupture model. The bathymetry and topography are adjusted to account for any uplifting or subsidence that would occur as a result of seafloor deformation. RMS generates initial wave conditions in the near-field from the seafloor deformation. Ocean Wave Propagation After the initial seafloor deformation and subsequent water displacement, RMS models the ocean wave propagation. RMS developed a numerical solver, implemented on Graphic Processing Units (GPUs), which uses a finite volume approach to approximate 2D shallow water wave equations over both the ocean and complex topography. In the near-field, inundation is sensitive to initial seafloor deformation, while in the far- field, inundation is more sensitive to magnitude and location of rupture Coastal Inundation As the wave enters shallow water and approaches the coast, RMS models the movement of water along the wet/dry interface using the RMS GPU-based solver, considering variable land friction.
- RMS has been performing unique high resolution tsunami modeling from credible earthquake related deformation along the key subduction zone plate boundaries round the world. Including those with the potential to affect Japan. Here we show the height of the tsunami in one of our simulations, for the region around Hong Kong, along with a representation of the concentrations of industrial facilities in Hong Kong along with some of the induatrial parks in the mainland region. We will be releasing these detailed tsunami footprints for managing accumulations along with detailed industrial park data for China.
- https://en.wikipedia.org/wiki/Tsunami#/media/File:Hurricane_Ike_Gilchrist_damage.jpg
- Reliable models of wind fields are crucial.
- Reliable models of wind fields are crucial.