This report presents an assessment of earthquake hazards in the Kingston, Jamaica Metropolitan area and was conducted as part of the Kingston Multi-Hazard Assessment under the US Agency for International Development funded Caribbean Disaster Mitigation Program. This assessment includes
Within the margin of error or uncertainty, the results of this assessment are consistently equal to or higher than previously published ground motion estimates for the Kingston Metropolitan area. The model presented here incorporates information from the historic record and from the geology and geophysics of the region. We feel that this type of model is more robust in that it does not solely rely on a historic record, which is short compared to the time between large earthquakes. Uncertainties in the basic parameters for a probabilistic seismic hazard assessment led to the definition of 32 different models. These 32 models were reduced to two final "best and worst case" models that encompassed the range of minimum and maximum ground motion estimates for the region. Within the Kingston Metropolitan area, 'hard rock' ground motions vary by as much as a factor of two and are consistently higher to the north and northeast than the southwest. The 10% probability of exceedence in 50 year acceleration values on hard rock range from 0.35 to 0.70g for the 'worst' case model to 0.15 to 0.40g for the 'best' case model.
Site conditions throughout the Liguanea Plain and Kingston Metropolitan area vary in terms of the types and thickness of soils and the degree of water saturation. Areas with water-saturated, unconsolidated soils and man made-ground are known to amplify strong ground motion by factors of two to three. Site conditions were evaluated using a number of approaches and techniques including
These site condition data are combined with the 'hard rock' ground motion estimates to develop a regional map of ground response for the Kingston Metropolitan area. It is important to realize that this assessment represents a regional model of earthquake activity and site response. Site-specific applications require detailed geo-technical analysis.
The major policy decisions about building codes, earthquake hazard mitigation, and redevelopment of the Kingston metropolitan area were made during an era of historically low seismic activity, following the 1907 earthquake. These policies need to be reevaluated in light of revised information about the likelihood of earthquakes in the immediate vicinity of the Kingston Metropolitan area and revisions of the seismic design criteria in the National Building Code.
Kingston ranks as the 7th largest natural harbor in the world and there is a large concentration of infrastructure throughout the Kingston Metropolitan area, including the Norman Manley International Airport, marine port facilities, oil refineries, and power generation plants. The region's demonstrated susceptibility to liquefaction and ground failure makes it extremely vulnerable to economic disruption as well as loss of life. Damage to port facilities during even a moderate sized earthquake, can delay post-earthquake relief efforts and have a significant long-term economic impact to industries dependent on air and marine commerce.
Expanded support for scientific and engineering research, coupled with the continued collection of earthquake data, is essential to 'fill the gaps' and reduce the uncertainties in the current state of knowledge and to improve future estimates of earthquake hazard in the Kingston Metropolitan area and Jamaica.
The primary project staff consisted of Margaret Wiggins-Grandison (Earthquake Unit, University of the West Indies, Mona Campus), Norman Harris (Mines and Geology Division, Ministry of Mining and Energy), Stuart Nishenko, Bill McCann and Maria Honeycutt (Natural Disaster Research, Inc). Jan Vermeiren and Steven Stichter (OAS) served as Project Officers, and along with Jennifer Worrell (USAID) provided support and encouragement. Other government and private organizations that made data available for this assessment include the Jamaican Water Resources Authority, Aeden Earle, and John Pereira (Urban Development Corporation). John Pereira (UDC), John Shepherd (UWI, Seismic Research Unit), Tina Neal (USGS), and Stuart Werner (Seismic Systems and Engineering Consultants) reviewed the Final Report and helped improve the overall presentation.
The success of the 1998 Kingston Gravity Survey described in Appendix A3 is due to the efforts of many individuals who worked long hours in the hot June sun. In addition to the primary project staff, thanks go to Miranda Chin, Doug Martin, and Bob Moose (National Ocean Survey) for collecting and reducing the gravity data, additional thanks are due Rollin Alveranga and Jackie DaCosta (Jamaica Prime Ministers Office), Anestoria Shalkowski (Office of Disaster Preparedness and Emergency Management), Glendon Newsome, Mr. McCook (Land Surveyors Association of Jamaica), Leeroy Bulgin, Noel Francis, Cynthia Edwards, John Marshall, and Donna Scott (Jamaica Survey Department) and Everald Scott for providing GPS equipment and field support during the survey. Special thanks to the Kingston Constabulary for accompanying the gravity survey teams through the Kingston metropolitan area.
Both the 1692 Port Royal and 1907 Kingston earthquakes dramatically demonstrated the vulnerability of the Kingston Metropolitan area to strong ground shaking. Ground motions, amplified by the unconsolidated and water saturated soils of the Palisadoes and the Kingston Harbor area, caused extensive building damage and ground failure. 2,000 people, approximately 1/4 of the population in Port Royal, perished in 1692. While there were fewer fatalities in 1907, 85% of the buildings were either damaged or destroyed. Losses, at the time of the event, are estimated at US$30 million dollars (Munich Re, 1998).
Since that time, Kingston has grown in population, industry, and commerce. This growth has also been accompanied by an increased vulnerability to natural disasters. Today, 750,000 people, about a third of Jamaica's population, reside and work in the Kingston Metropolitan area. As the national capital and the 7th largest natural harbor in the world, the Kingston area contains the island's largest concentration of commerce, industry, financial services, government, and infrastructure.
Following the 1907 earthquake, Kingston adopted strict building codes. The majority of growth in the Kingston area since 1907, however, has occurred during a period of low earthquake activity. Local codes and building practices have not been 'put to the test' for most of the 20th century. While the recent 1993 Woodford earthquake produced only moderate damage, it did serve as a "wake-up" call for earthquake hazard mitigation in Jamaica.
In addition to basic life safety issues, moderate-sized earthquakes can impact critical infrastructure in the Kingston Metropolitan area including the Norman Manley International Airport, power generation stations, oil refineries, and various marine port facilities. Damage to port facilities during even a moderate sized earthquake, can delay post-earthquake relief efforts and have a significant long-term economic impact to industries dependent on air and marine commerce.
The impact of natural disasters on the nations and economies of the Caribbean region have been substantial. Disasters have impeded the fulfillment of long-term development goals and the balance of payments. Disasters have also impacted investor confidence either through the flight of foreign investment capital or the requirement of higher rates of return to compensate for perceived risks.
While disasters have serious impacts on development, poorly planned development greatly increases the risk of disaster. There is a recognized need to include mitigation and risk management as an integral part of economic and socially sustainable development. Recent natural disasters worldwide have repeatedly demonstrated the value of proactive policies that encourage both disaster preparation and prevention.
The Caribbean Disaster Mitigation Project (CDMP) was formulated by the United States Agency for International Development (USAID) and the Organization of American States (OAS) in 1993 for the purpose of providing technical assistance for disaster mitigation to nations of the Wider Caribbean Region. The CDMP sought to establish public/private sector mechanisms that could measurably lessen the loss of life, reduce the potential for physical and economic damage, and shorten the disaster recovery period. CDMP activities and projects include natural hazard assessments and risk mapping, the promotion of hazard-resistant building practices and standards, the incorporation of hazard mitigation in post-disaster recovery, and technical training and information dissemination. These activities are described in detail on the CDMP World Wide Web site http://www.oas.org/en/cdmp.
The Kingston Multihazard Assessment Project was one of the first CDMP projects to be undertaken and addressed landslide, seismic, and coastal storm hazards for the Kingston Metropolitan area. The study area for the Kingston Multihazard Assessment includes the parishes of Kingston and St. Andrew and the Portmore area of southeastern St. Catherine parish, incorporating the largest centers of population on the island (see Figure 1.1).
Two goals of the CDMP are to promote sustainable development by reducing vulnerability to natural hazards in existing and planned development, and to promote public awareness and development decision making by accurately mapping hazard prone areas. The Kingston Multihazard Assessment resulted in the compilation and presentation of various types of geologic hazard information in traditional and Geographic Information System (GIS) formats. These studies and maps are meant to aid policy decision making and to support the incorporation of mitigation in land use planning, the location of physical development, and the revision of building codes. Project descriptions and maps can be found at http://www.oas.org/en/cdmp/hazmap/kma.htm.
The Kingston Seismic Hazard Assessment portion of the KMA began in 1995 and involved personnel from the Earthquake Unit, University of the West Indies, Mona Campus; and the Mines and Geology Division, Ministry of Mining and Energy. Natural Disaster Research Inc. served as technical advisor and project manager.
The Kingston Seismic Hazard Assessment was split into two phases. Phase One focused on collecting, organizing, and analyzing the basic geologic and earthquake data that would serve as input to the seismic hazard assessment in Phase Two (Wiggins-Grandison, 1997). These data included a catalog of seismicity in and around the island of Jamaica, a seismotectonic model of the region, and GIS databases of the surface geology, the seasonal variations in water table and a digital elevation model (DEM) for the Kingston Metropolitan Area. Additional data were collected from well logs for depth to basement and site characterization studies. A gravity survey was conducted in June 1998 to provide additional estimates of the depth to basement beneath the Liguanea Plain.
These data were used in Phase Two to develop estimates of earthquake ground motion (peak acceleration) on hard rock that have a 10% and 50% probability of exceedence in 50 years. These 'hard rock' ground motions were then modified to account for local site conditions to arrive at a seismic hazard estimate for the Kingston Metropolitan area.
The analysis in Phase Two involves a number of discreet steps that are listed below and discussed in the sections indicated. Figure 1.2 presents a flowchart that summarizes the analysis.
The Discussions and Recommendations of the Kingston Seismic Hazard Assessment are presented in Section 6. Readers not interested in the details of the seismic hazard analysis can proceed directly to the Discussions and Recommendations section without loss of content.
The Reference/ Bibliography includes both recent and historic references to Jamaican geology and seismology.
The accompanying Appendix contains the maps and data sets that were produced for this study during Phases One and Two and include the Jamaican earthquake catalog, a history of the Jamaican Seismograph Network and a network magnitude calibration (Appendix 1); well logs, depth to basement and seasonal water table maps (Appendix 2), and data and shallow-structure models from the 1998 Kingston gravity survey (Appendix 3). Some of these data are also available as digital files at http://www.oas.org/en/cdmp/hazmap/kma.htm.
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Page Last Updated: 20 April 2001