UN-ECLAC Disaster UN-ECLAC Disaster

Assessment MethodologyAssessment Methodology

The Coastal Zone: Hazards to the Coastal Areas of

Caribbean SIDS Presented by

David A.Y. Smith, Ph. D. P.Eng.Managing Director, Smith Warner International Ltd.

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Hazards affecting the Hazards affecting the CaribbeanCaribbean

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ObjectivesObjectivesPrimary objectives of this session are: To give an overview of the various hazards that can

affect the Caribbean region in general.

· To provide some indication of the consequences of these hazards, their frequencies of occurrence and some historic patterns of impact.

·  To promote a better understanding of the mechanisms underlying these hazards.

·  To set the stage for the necessary reconstruction efforts and for mitigation of future damage.

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Profile of the Caribbean and Profile of the Caribbean and its Coastal Areasits Coastal Areas

Can be divided into Greater Antilles/Lesser Antilles – based on location and geological origin

All islands have high coastline to area ratios, and are therefore particularly vulnerable to coastal hazards.

There are differing levels of risk across the whole Caribbean basin.

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Coastal Hazards in the Coastal Hazards in the CaribbeanCaribbean

Greater Antilles

(Cuba, Jamaica, Hispañola, Puerto Rico)

•Hurricanes

•Floods

•Earthquakes

•Tsunamis

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.

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Coastal Hazards in the Coastal Hazards in the Caribbean (cont’d)Caribbean (cont’d)

1980-89

Dominican Republic Haiti

Jamaica Puerto Rico

Cuba Windward Islands

Leeward Islands Belize

Bahamas

Fatalities in the Insular Caribbean and Belize by Type

0

500

1000

1500

2000

1970-1979 1980-1989 1990-1998

Decade Ranges

Nu

mb

er

of

Fa

talit

ies

Floods

Wind

Other

Hurricanes: Hurricanes: A Primary Hazard for A Primary Hazard for

Caribbean SIDSCaribbean SIDS

Hurricane Keith approaching Belize, 2000

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Hurricane Damage:Hurricane Damage:Occurs primarily from:

– Hurricane waves; – Storm surge and;– Beach erosion.

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Hurricane WavesHurricane Waves Waves generated by hurricanes can be

very damaging. Estimates of extreme (i.e. design) wave heights made throughout the region are summarized following:

Island 1 in 50 year wave (m)

1 in 100 year wave

(m)

Jamaica 7.6 8.6

Antigua 13.3 14.9

Grenada 8.1 9.6Port Zante, St. Kitts (Hurricane Lenny, 1999)

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Hurricane Waves (cont’d)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, eroding shorelines.

Deep water waves change in height as they travel in to shallower water.

West coast road, Grenada – Hurricane Lenny, 1999

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Hurricane Waves (cont’d)Hurricane Waves (cont’d) Hurricanes waves at the shoreline can also

cause extensive damage to infrastructure, boatyards, etc.

Grenada boatyard, Hurricane Ivan, 2004

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Hurricane Waves (cont’d)Hurricane Waves (cont’d) Hurricane waves and storm surge can have

tremendous power

Trident Hotel, Jamaica after Hurricane Allen, 1980

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Beach ErosionBeach Erosion The erosion is

exacerbated where there are buildings (i.e. vertical walls) in the wave run-up zone.

Coastal development must be carefully designed so as not to negatively impact adjacent shoreline areas.

NE Ambergris Caye, Hurricane Dean, 2007

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Beach Erosion (Cont’d)Beach Erosion (Cont’d) 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.Grace Bay, TCI – Hurricane Jeanne (T. Richardson)

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Components of Storm Components of Storm SurgeSurge

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Components of Storm Surge Components of Storm Surge (cont’d)(cont’d)

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Characteristics of Storm Characteristics of Storm SurgeSurge

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Examples of Storm Surge Examples of Storm Surge

Inundation of waterfront promenade, Dominica (Lenny, 1999)

High storm waves

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Hazard Mapping – Storm Hazard Mapping – Storm Surge (Providenciales, TCI)Surge (Providenciales, TCI)

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Hazard Hazard Mapping – Mapping –

Storm SurgeStorm SurgeGrand Grand

Turk,TCITurk,TCI

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Hurricanes in the Caribbean: Hurricanes in the Caribbean: Historical AccountHistorical Account

Records of hurricane damage exist in the archives of the Caribbean for over five centuries;

Since approximately 1900, hurricane records and hurricane 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.

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Hurricanes in the Caribbean: Hurricanes in the Caribbean: Spatial DistributionSpatial Distribution

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 aspects that are vulnerable to the hazards;

Latest research indicates possible climate change impacts (more intense storms).

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Distribution of hurricane Distribution of hurricane activityactivity

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Flooding: Flooding: A risk to property and A risk to property and

productivityproductivity

Over 1300 lives lost to flooding in Caribbean over last 20 years

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Flooding in the Caribbean: Flooding in the Caribbean: Historical AccountHistorical 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 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.

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Earthquakes: Earthquakes: A risk to property and lifeA risk to property and life

Intensity

Effects

I Not felt.

II Felt by persons at rest.

III Felt indoors. Hanging objects swing.

IV Vibration like passing of heavy truck. Objects swing.

V Felt outdoors. Sleepers wakened.

VI Felt by all. All objects shake. Some breakage.

VII Difficult to stand. Damage to masonry.

VIII Difficult to drive. Damage to infrastructure.

IX Masonry destroyed.

X Foundations destroyed.

XI Underground infrastructure out of service.

XII Total damage.

The Modified Mercalli Scale

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EarthquakesEarthquakes and and VolcanoesVolcanoes in the in the

CaribbeanCaribbeanThe 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.

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Some earthquakes in the Some earthquakes in the CaribbeanCaribbean

Major Earthquakes– Port Royal, Jamaica (1692)– Trinidad (1766)– Antigua (1843)

Minor Events– St. Lucia (1953)– Trinidad (1954)– Antigua (1974)

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Plate Tectonic SettingPlate Tectonic Setting

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Volcanoes:Volcanoes:A risk to property and lifeA risk to property and life

A significant Hazard in the Lesser Antilles

•Soufriere, St. Vincent (1718, 1812, 1902-3, 1979)

•Mt. Pelee, Martinique (1902, 1929-32)

•Soufriere Hills, Montserrat (1997)

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Soufriere Hills, Montserrat

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Plymouth, Montserrat

Before After

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Volcanoes in the Volcanoes in the Caribbean: Historical Caribbean: Historical

AccountAccount 17 Volcanoes have 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.

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Tsunamis: Tsunamis: are we at risk?are we at 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.

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Tsunamis in the Tsunamis in the Caribbean: Historical Caribbean: Historical

AccountAccountSummary Table of Tsunami Activity

Date Location Comment 1897-Nov-29 West Indies Large tsunami at Montserrat 1907-Jan-14 Jamaica Tsunami generated, main damage at Kingston 1918-Oct-11 Puerto Rico Tsunami caused fatalities and damage at Point

Borinquen and Aguadilla; also damage at Mayaguez

1946-Aug Dominican Republic

Town of Matanzas badly damaged and abandoned; more than 100 persons killed; minor damage on coast of Haiti

1953-May-31 Dominican Republic

Very slight tsunami; amplitude 0.2 ft at Puerto Plata

1955-Jan-18 Venezuela Tsunami caused damage at La Vela, Venezuela

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Tsunami Risk ZonesTsunami Risk Zones

•Tsunami triggered by seismic activity; submarine landslides.

•Resulting waves could be of the order of 4m (Cat 1-2)

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