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UN-ECLAC Disaster Assessment Methodology UN-ECLAC Disaster Assessment Methodology The Coastal Zone: Summary of Caribbean Risks, Hazards and Vulnerabilities.

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Presentation on theme: "UN-ECLAC Disaster Assessment Methodology UN-ECLAC Disaster Assessment Methodology The Coastal Zone: Summary of Caribbean Risks, Hazards and Vulnerabilities."— Presentation transcript:

1 UN-ECLAC Disaster Assessment Methodology UN-ECLAC Disaster Assessment Methodology The Coastal Zone: Summary of Caribbean Risks, Hazards and Vulnerabilities

2 ECLAC Disaster Assessment Methodology Objectives Primary objectives of this session are: To familiarize the user with the various hazards that can affect the Caribbean region in general, while giving an indication of country specific occurrences of disaster.  To provide some indication of the consequences of these hazards, their frequencies of occurrence and historic patterns of impact.  To develop a better understanding of the mechanisms of these hazards.  To set the stage for the necessary reconstruction mechanisms and for mitigation of future damage.

3 ECLAC Disaster Assessment Methodology Profile of the Caribbean & Coastal Areas Can be divided into Greater Antilles/Lesser Antilles – based on location and geological origin All are islands with high coastline to area ratios, and are therefore particularly vulnerable to coastal hazards. Apparently differing levels of risk between Windward and Leeward Islands

4 ECLAC Disaster Assessment Methodology Coastal Hazards in the Caribbean Greater Antilles (Cuba, Jamaica, Hispañola, Puerto Rico) Hurricanes Floods Earthquakes Lesser Antilles (St. Maarten to Trinidad) Hurricanes Volcanic Eruptions (Ash fallout) Earthquakes Tsunamis Over 6000 lives lost in the Caribbean over past 30 years due to natural disasters.

5 ECLAC Disaster Assessment Methodology Coastal Hazards in the Caribbean (cont’d)

6 Hurricanes: A Primary Source of Risk to Caribbean Coastal Infrastructure

7 ECLAC Disaster Assessment Methodology The Saffir-Simpson Scale STATUS WINDS (km/hr) WINDS (mph) PRESSURE Depression<56<35 mph------ Tropical Storm56-11735-73 mph------ Category 1118-15274-95 mph966 mb> Category 2153-17696-110 mph980-965 mb Category 3177-208111-130 mph964-945 mb Category 4209-248131-155 mph944-920 mb Category 5248 +155 mph+<920 mb

8 ECLAC Disaster Assessment Methodology Damage from Hurricanes Occurs primarily from: – Hurricane waves; – Beach scour and; – Storm surge.

9 ECLAC Disaster Assessment Methodology Hurricane Waves Deep water waves resulting from hurricanes can be very damaging. Estimates of extreme (I.e. design) wave heights made throughout the region are summarized following: Island1 in 50 year Return period (m) 1 in 100 year (m) Jamaica7.68.6 Antigua13.314.9 Grenada8.19.6 Port Zante, St. Kitts

10 ECLAC Disaster Assessment Methodology Hurricane Waves (cont’d) These changes result from interactions between the waves and the seabed, other waves and wind inputs. At the shoreline, they can be very damaging, breaking out infrastructure and eroding shorelines. These deep water waves change in height as they travel in to shallower water. West coast, Grenada

11 ECLAC Disaster Assessment Methodology Beach Scour During a storm event, the extreme wave energy often results in severe erosion of the beach and/or shoreline. This erosion may reach up to 20-30 m inland, depending on the storm severity, and can totally wipe out beach areas and adjacent infrastructure. West coast, St. Lucia

12 ECLAC Disaster Assessment Methodology Beach Scour The erosion is exacerbated where there are buildings (i.e. vertical walls) in the wave run-up zone. Shore protection methods must be carefully designed so as not to negatively impact adjacent shoreline areas. After Hurricane Lenny

13 ECLAC Disaster Assessment Methodology Components of Storm Surge

14 ECLAC Disaster Assessment Methodology Components of Storm Surge

15 ECLAC Disaster Assessment Methodology Example of Storm Surge Inundation of waterfront promenade, Dominica High storm waves

16 ECLAC Disaster Assessment Methodology Hurricanes in the Caribbean: Historical Account Records of hurricane damage exist in the archives of the Caribbean for over five centuries; Since approximately 1900, detailed hurricane records and characteristics have been maintained by the National Hurricane Center (NHC) and NOAA in Florida, USA. These records have improved in accuracy and detail since the 1950’s, first with the ability of special reconnaissance aircraft to fly into the eye of these storms, and later, with the aid of satellite imagery.

17 ECLAC Disaster Assessment Methodology Hurricanes in the Caribbean The records over the past century show a wide band of hurricane activity across the Caribbean, with the least activity occurring in the area of Trinidad; In general, damage has occurred from storm surge, waves, wind and rainfall, as all of the islands have vulnerable aspects to them; Latest research indicates climate change impacts.

18 ECLAC Disaster Assessment Methodology Hurricanes passing close to Jamaica 1980-1999

19 ECLAC Disaster Assessment Methodology Flooding: A source of risk to coastal property and productivity Over 1300 lives lost to flooding in Caribbean over last 20 years

20 ECLAC Disaster Assessment Methodology Flooding in the Caribbean: Historical Account In the Lesser Antilles, flooding has been associated primarily with tropical waves or hurricanes; Flooding may take the form of excessive ponding, as occurred in Antigua in Antigua during Hurricane Lenny, or flash flooding as can occur in the more hilly or mountainous islands such as Nevis and Dominica; In general, all of the islands and their communities are vulnerable to flooding and drainage systems need to be designed to take this into account.

21 ECLAC Disaster Assessment Methodology Flood Consequences in Jamaica Eroded river beds and cut- off roads. Damaged bridges Slope stability problems. Landslides and mudslides.

22 ECLAC Disaster Assessment Methodology Earthquakes: A source of risk to property and life IntensityEffects INot felt. IIFelt by persons at rest. IIIFelt indoors. Hanging objects swing. IVVibration like passing of heavy truck. Objects swing. VFelt outdoors. Sleepers wakened. VIFelt by all. All objects shake. Some breakage. VIIDifficult to stand. Damage to masonry. VIIIDifficult to drive. Damage to infrastructure. IXMasonry destroyed. XFoundations destroyed. XIUnderground infrastructure out of service. XIITotal damage. The Modified Mercalli Scale

23 ECLAC Disaster Assessment Methodology Earthquakes and Volcanoes in the Caribbean The Caribbean Region, Central and South America are characterized by a belt of seismicity. This is depicted here, with volcanic epicentres shown as green triangles and earthquake epicenters shown as orange dots.

24 ECLAC Disaster Assessment Methodology Earthquakes in the Caribbean Major Earthquakes – Jamaica (1692) – Trinidad (1766) – Antigua (1843) Minor Events – St. Lucia (1953) – Trinidad (1954) – Antigua (1974)

25 ECLAC Disaster Assessment Methodology Volcanoes: A source of risk to property and life A significant Hazard in the Lesser Antilles Soufriere (1718, 812, 1902-3, 1979) Mt. Pelee (1902, 1929- 32) Soufriere Hills (1997)

26 ECLAC Disaster Assessment Methodology Soufriere Hills, Montserrat

27 ECLAC Disaster Assessment Methodology Plymouth, Montserrat

28 ECLAC Disaster Assessment Methodology Volcanoes in the Caribbean: Historical Account 17 Volcanoes erupted in the Eastern Caribbean. 25 Volcanic Centres with the potential to erupt. Approx. 40,000 lives lost in 1902 eruptions (St. Vincent and Martinique). Warning time has ranged from 14 days to 14 years. The famous Port Royal disaster of 1692 was initially caused by an earthquake which liquefied an alluvial plane causing it to slide into the sea, the resulting tsunami was several metres in height and caused over 2000 deaths.

29 ECLAC Disaster Assessment Methodology Tsunamis: another source of risk More a problem in the Lesser Antilles Caused by ocean centred earthquakes, or volcanic eruptions. Greatest risk presently posed by “Kick ‘em Jenny” SeaBeam image of Kick 'em Jenny constructed from measurements taken from the NOAA Research Vessel Ronald H. Brown on March 12 2002.

30 ECLAC Disaster Assessment Methodology Tsunamis in the Caribbean: Historical Account

31 ECLAC Disaster Assessment Methodology Tsunami Risk Zones

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