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

UN-ECLAC Disaster UN-ECLAC Disaster

Assessment MethodologyAssessment Methodology

The Coastal Zone: Summary of Caribbean Risks, Hazards and Vulnerabilities

ECLAC Disaster Assessment Methodology

ObjectivesObjectivesPrimary 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.


Profile of the Caribbean & Profile of the Caribbean & Coastal AreasCoastal 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


Coastal Hazards in the Coastal Hazards in the CaribbeanCaribbean

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.


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 Source of Risk A Primary Source of Risk

to Caribbean Coastal to Caribbean Coastal InfrastructureInfrastructure


Damage from HurricanesDamage from Hurricanes

Occurs primarily from: – Hurricane waves; – Beach scour and;– Storm surge.


Hurricane WavesHurricane 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:

Island 1 in 50 year Return

period (m)

1 in 100 year (m)

Jamaica 7.6 8.6

Antigua 13.3 14.9

Grenada 8.1 9.6Port Zante, St. Kitts


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, breaking out infrastructure and eroding shorelines.

These deep water waves change in height as they travel in to shallower water.

West coast, Grenada


Beach ScourBeach 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


Beach ScourBeach 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


Components of Storm Components of Storm SurgeSurge


Components of Storm SurgeComponents of Storm Surge


Example of Storm Surge Example of Storm Surge

Inundation of waterfront promenade, Dominica

High storm waves


Hurricanes in the Hurricanes in the Caribbean: Historical Caribbean: Historical

AccountAccount 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.


Hurricanes in the Hurricanes in the CaribbeanCaribbean

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.


Hurricanes passing close Hurricanes passing close to Jamaica 1980-1999to Jamaica 1980-1999


Flooding: Flooding: A source of risk to coastal A source of risk to coastal property and productivityproperty and productivity

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


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 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.


Flood Consequences in Flood Consequences in JamaicaJamaica

•Eroded river beds and cut-off roads.

•Damaged bridges

•Slope stability problems.

•Landslides and mudslides.


Earthquakes: Earthquakes: A source of risk to property and A source of risk to property and

lifelifeIntensity

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


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.


Earthquakes in the Earthquakes in the CaribbeanCaribbean

Major Earthquakes– Jamaica (1692)– Trinidad (1766)– Antigua (1843)

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


Volcanoes:Volcanoes:A source of risk to property and A source of risk to property and

lifelifeA significant Hazard in the Lesser Antilles

•Soufriere (1718, 812, 1902-3, 1979)

•Mt. Pelee (1902, 1929-32)

•Soufriere Hills (1997)


Soufriere Hills, Montserrat


Plymouth, Montserrat


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

AccountAccount 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.


Tsunamis: another source Tsunamis: another source of riskof 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.


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

AccountAccountDate 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


Tsunami Risk ZonesTsunami Risk Zones


Documents

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