Building a Spatial Database for Earthquake Risk Assessment and Management in the Caribbean Jacob Opadeyi and Rehanna Jadoo Department of Geomatics Engineering and Land Management, The University of the West Indies, St. Augustine, Trinidad, West Indies. Email: jopadeyi@hotmail.com
OUR VULNERABLE LAND MASS Housing developments on drainage channels and steep slopes Unapproved development and land squatting Voluntary approach to the use of building codes Active seismic activities with geological faults Low level of awareness on the impact of natural hazards Low level of real estate insurance
Geomorphology and Land cover 2007
Roads and Building Density
Slope and Soils Erosion
THE CONSEQUENCES
Damage to Buildings in Haiti due to the Earthquake of 2010
Risk Management Framework Risk management Description of intention Hazard mapping Risk evaluation Vulnerability assessment Risk estimation Estimation of probability of consequences Estimation of magnitude of consequences
EARTHQUAKE RISK ASSESSMENT What is Risk? Risks are an integral part of life and since risk cannot be completely eliminated, the only possible option is to assess and manage it. The first step in risk assessment is to find out what the problems are. This involves evaluating the significance of a given quantitative measure of risk in an integrated way.
EARTHQUAKE RISK ASSESSMENT Earthquake risk assessment encompasses the range of studies required to estimate the likelihood and potential consequences of a specific set of earthquakes of different magnitudes and intensities. Seismic scientists and engineers provide the key decision-makers with a description of the nature of the earthquake risk in specific regions as well as the degree of uncertainty surrounding such estimates. Quantitative estimates of seismic risk are important for judging whether earthquakes represent a substantial threat at any location as they enable objective weighting of earthquake risk relative to other natural hazards and other priorities for making design and retrofit decisions (NRC, 1996.)
Methods 4 major steps (Batuk et al 2005) 1. Hazard Analysis quantifies the physical characteristics of a hazard, including probability of occurrence, magnitude, intensity, location, influence of geological factors 2. Exposure Analysis identifies and maps underlying elements at risk or exposures, including the built environment and socioeconomic factors such as population and economic activity 3. Vulnerability Analysis: Assesses the degree of susceptibility to which elements at risk are exposed to the hazard. A common form of vulnerability analysis uses historical damage records to prescribe relationships between damage to dwellings and hazard intensity, for example different buildings and construction types will have distinct vulnerability curves, and finally 4. Risk analysis synthesizes the above three components and determines the resulting losses as a function of return period or as an exceedance probability: e.g. RISK ($$/YR) = SUM( HAZARD [YEAR -1 ] X ASSETS [$$] X FRAGILITY [0-1])
Uses of Earthquake Risk Assessment (C. Benson and J. Twigg, 2004) Predicting the expected impact of earthquakes Identification of appropriate risk management strategies Predicting the impact a project would have on forms and level of vulnerability in the wider community Help to formulate national policy objectives such as land use planning and building codes it provides cost efficient decision support on how to optimize investments into risk reducing measures in three situations, namely, prior, during and after an earthquake.
Data Required for Earthquake Risk Assessment A. Baseline data - Administrative boundary - Land cover, roads, streams etc. - Transportation and utility system - Facility and building structures - Demography (census, population distribution, density) - Economic value of asset of various sectors
Data Required for Earthquake Risk Assessment B. Hazard data Historical records (time, place, extent, magnitude / intensity) of earthquake hazard Geology, lithology, soil, and slope, water table Faults location, length, and depth Site condition, ground motion Existing method in hazard & risk assessment methodology
Data Required for Earthquake Risk Assessment C. Vulnerability data Proximity of assets to active and inactive fault lines Age of structures Population and development density Value of assets Location of critical facilities: Hospitals, Schools, Prisons, Banks, Public offices Construction materials used in buildings Location of lifelines: telecommunication, water, gas, power, transport systems
EARTHQUAKE RISK MANAGEMENT What is Risk Management? Risk management means reducing the threats to life, property and the environment posed by the hazard whilst simultaneously accepting unmanageable risks and maximizing any associated benefits (Smith, 1996.) Risk management involves the efforts of a variety of sectors and series of actions. In the case of earthquakes, risk management describes the role of seismic monitoring in developing alternative strategies for reducing future losses and aiding the recovery process.
Earthquake Risk Management Measures National risk reduction program Disaster preparedness and response plans Disaster recovery plans (National and sectoral) Earthquake hazard maps Earthquake early warning systems Landuse planning Building codes and development regulations Insurance schemes Development incentive programmes Efficient risk communication strategies Public education (use of simulators) Research and development programmes Earthquake risk policy and legislation
Example of Seismic Assessment Products Figure 1 Colour Coded Seismic Hazard Map pubs.usgs.gov/fs/2003/fs017-03/images/useqs.gif; Figure 2 Source: www.consrv.ca.gov/cgs/rghm/psha/pages/index.aspx; Figure 3Source: Seismic risk mapping in Germany, Tyagunov et al 2006
Case Study: Comprehensive Earthquake Risk Reduction Program and Action Plan: Marikina Task 1. Stakeholder User Needs Assessment: The first task will identify primary stakeholder concerns and interests. Using available GIS data and scenario modeling, it characterized stakeholder concerns in terms of known earthquake risk to valued community assets. Task 2. Data Inventory Comparison of existing GIS data resources with needs emerging from Task 1 Analyzes data collection and integration issues. Task 3. Risk Assessment Formalization of findings from a risk assessment regarding loss of housing, critical infrastructure, and economic development opportunities resulting from a 7.0 Magnitude earthquake.
Peak Ground Acceleration Map Overlaid on landuse to show areas subject to Heavy Shaking
Peak Ground Acceleration Map & Critical Facilities Subject to Heavy Shaking
Comprehensive Earthquake Risk Reduction Program and Action Plan: Marikina Task 4. Prepare Conceptual Earthquake Risk Reduction Plan. This task created a conceptual framework based on a strategic planning process It assesses implementation options for the Comprehensive Earthquake Risk Reduction Program including locally feasible goals and objectives, policies/strategies and programs/projects for mitigation, preparedness, response, and recovery.
Comprehensive Earthquake Risk Reduction Program and Action Plan: Marikina Task 5. Plan Refinement and Implementation Strategy This task combined objectives, policies, strategies, programs and projects for mitigation, preparedness, response, and recovery actions into a Draft Comprehensive Earthquake Risk Reduction Program and Action Plan based on discussions held at stakeholders workshop. Task 6. Produce Final Products This task will include finalization of the Program and Action Plan along with Web-based materials.
Feature Identity Database The feature identity database is made up of variables that provide general information about the facility e.g. location, name, contact information, name of person in charge etc. Many of these variables can be collected in the field using mobile GPS/GIS technology. Fac_ID P_KEY Nfac_ Code 23 12 Health center Fac_Type Name Address Locality Tel Fax Chaguanas District Health Facility Corner Galt St. and Chaguanas Main Rd. Chaguanas 665-8958 24 61 Police Station Chaguanas Police Station Railway Rd. Chaguanas 665-5271 National Helicopter Services 25 41 Air Field / Runway Ltd. NHSL Heliport, Camden Couva 679-2628 679-2345 26 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX 27 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX 28 XX XXXXXXXXX XXXXXXXXXXXXXXXXXXX XXXXXXXXXXXXXXXXXXXXXX XXXXX XXXXXXX XXXXXX
Feature Amenities Database The feature amenities database is made up of variables that provide information about the facility s service amenities. This data should be collected by the relevant agency (government / private) responsible for the facility. Amen _ID 10 11 12 13 14 15 Fac_ID F_KEY Floor_space Parking_sp Parking_ sz Generator Water _cap Pump 23 2400 20 70 YES XXX YES XX 24 XXXXXXXXXX XX XXXXXX YES XXX YES XX 25 XXXXXXXXXX XX XXXXXX YES XXX YES XX 26 XXXXXXXXXX XX XXXXXX 27 XXXXXXXXXX XX XXXXXX 28 XXXXXXXXXX XX XXXXXX Toilets_ unisex
Feature Functions Database The feature functions database is made up of variables that provide information about the facility s operations. These variables will depend on the type of facility. For example, the variables for a medical facility will include : Number of beds, Number of doctors, Number of nurses etc. This data should be collected by the relevant agency (government / private) responsible for the facility. Fac_ID P_KEY Health_ Beds N_Doctors N_Nurses N_Ambulances N_Drivers T_staff 23 32 34 36 60 XXX XXX XX XX XXXX 136 XXX XXX XX XX XXXX 95 XXX XXX XX XX XXXX 200 XXX XXX XX XX XXXX
Structural Integrity Database The structural integrity database is made up of variables that provide information about the integrity of the facility s construction design. This data should be compiled by engineering, construction and inspection experts, in coordination with the relevant agency (government / private) responsible for the facility. Examples of variables that should be included and assessed include vulnerability of building foundation, columns, beams, supporting walls etc.
Structural Integrity Database These variables can be further broken down into more detailed evaluations and tests as deemed necessary by relevant experts. This information can be used to asses the facility s structural vulnerability to the effects of earthquakes or other natural disasters. Struc Fac_ID Found_v Column_ Supp_walls Beam Floor_slab yrs_safe _ID F_KEY uln vuln _vuln _vuln _vuln _usage 100 23 XX XXX XXX XX XX XXXX Damage _history Earthquake Response Possible closure_reccom 101 32 XX XXX XXX XX XX XXXX 102 34 XX XXX XXX XX XX XXXX 103 36 XX XXX XXX XX XX XXXX
Compiling the National Built Assets Database Feature Amenities Database Feature Identity Database Chaguanas District Health Center FAC_ID 23 Feature Functions Database Structural Integrity Database
Synchronization of Data with ArcGIS Hyperlink images of facility and building plans. Front View Side View 1 st Floor 2 nd Floor 3 rd Floor
Query & Analyse National Database of Built Assets Many questions can be answered by querying and analysing this database, along with the associated bio-physical characteristics of the land, providing decision-support for policymakers: How many built assets throughout the country require seismic retrofitting? Which facilities have been designated as shelters in the event of a natural disaster? Where are these shelters located? What is the potential monetary loss/replacement cost should one/more of these built assets collapse due to an earthquake? Which facilities exist within the most hazardous zones? In the event of an evacuation how many occupants will require special assistance?
Building Density in Anguilla
Building Density in Antigua
Building Density in Tortola
What are the Challenges facing the Development of Earthquake Risk Assessment and Management in Trinidad & Tobago? Lack of a consistent data collection programme for risk assessment and management. Lack of an active public education programme. A need for capacity development and enhancement Review of relationship with related agencies Lack of a database on building structures Vulnerability assessment of communities Obtaining political support
Thank you