perspectives on earthquake risk assessment and...
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National Consultation on Earthquake Safety in Trinidad and Tobago July 5-6, 2010
Perspectives on Earthquake Risk Assessment
and Management in Trinidad and Tobago
Jacob Opadeyi
Professor and Head
Department of Geomatics Engineering and Land Management,
The University of the West Indies , St. Augustine,
Trinidad, West Indies.
Email: [email protected]
National Consultation on Earthquake Safety in Trinidad and Tobago July 5-6, 2010
OutlineReview of Concepts
Risk Assessment methods
Data requirements
Users and users of Earthquake risk assessment results
Risk management activities
Towards a Earthquake Risk Reduction Plan for T&T
Prof. Jacob Opadeyi
•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
OUR VULNERABLE LAND MASS
Prof. Jacob OpadeyiNational Consultation on Earthquake Safety in Trinidad and Tobago July 5-6, 2010
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
Description of
intentionHazard
mapping
Vulnerability
assessment
Estimation of
magnitude of
consequences
Estimation of
probability of
consequences
Risk estimation
Risk evaluation
Risk managemen
t
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.)
Methods4 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
National Consultation on Earthquake Safety in Trinidad and Tobago July 5-6, 2010
Uses of Earthquake Risk Assessment (C. Benson and J. Twigg, 2004)
•Predicting the expected impact of earthquake of projects
•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.
Prof. Jacob Opadeyi
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 demographic data
Value and replacement cost 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
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.
Estimated Ground Shaking for Metro Manila in a
7.0 Magnitude Earthquake along the West Valley
Fault
Existing and Planned Land Use Map of Metro
Manila
Peak Ground Acceleration Map and Commercial &
Industrial 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 Disaster Reduction
Program and Action Plan: Marikina
Critical FacilitiesObjective 1: Protect and strengthen infrastructure facilities to prevent loss of lives and damage to
properties, to allow continued use, and to restore normalcy quickly following disasters.
Policy 1.1: Report to the people concerned whether public and private buildings and infrastructure are in
good condition.
Program/Project
1.1.1 Develop pre-
disaster inventories
of all utility lines to
expedite post
disaster identification
of damaged facilities.
1.1.2 Study the
replacement or
upgrading of critical
facilities particularly
water lines.
1.1.3 Study the
replacement or
upgrading of power
and telecommunication
facilities.
Project 1.1.4 Establish a full
coordination system with utility
companies. Develop
methods to ensure effective inter-
provider coordination systems to
reasonable levels of service
subsequent to a damaging
earthquake
Critical Facilities
Objective 1: Protect and strengthen infrastructure facilities to prevent loss of lives and
damage to properties, to allow continued use, and to restore normalcy quickly following
disasters.
Policy1.2 : Preserve route functionality of roads and bridges for evacuation and logistics
under all circumstances.
Program/Project
1.2.1 Study the vulnerability of existing
roads and bridges and investigate
possible improved locations in relation to
land use.
1.2.2 Construct new
major roads and
bridges.
1.2.3 Retrofit
infrastructure facilities
which need to be
strengthened.
Critical Facilities
Objective 1: Protect and strengthen infrastructure facilities to prevent loss of lives and
damage to properties, to allow continued use, and to quickly restore normalcy following
disasters.
Policy 1.3 : Construction of public and private facilities should take into account potential
earthquake threats including liquefaction.
Program/Project
1.3.1 Identify
earthquake hazard-
prone areas and
areas safe for the
location of public and
private utilities and
facilities
1.3.2 Modify the City
Comprehensive Land
Use Plan to reflect
safe
locations for public
and private facilities.
1.3.3 Construct public
and private facilities
such as roads and
bridges with
adequate mitigation
measures.
1.3.6 Require
public and private
facilities to
address potential
earthquake
hazards.
Critical Facilities
Objective 1:Protect and strengthen infrastructure facilities to prevent loss of lives and damage
to properties, to allow continued use, and to restore normalcy quickly following disasters.
Policy 1.4 : Restrict land uses downstream from the proposed road dike levees unless such
facilities have been determined to incorporate adequate seismic stability.
Program/Project
1.4.1 Identify earthquake hazard-
prone areas and safe areas to
locate road dike
levees
1.4.2 Develop a land use
plan for the location of road
dike levees
1.4.3 Develop an
evacuation plan in case of
levee damage
Others: New Buildings, Existing Buildings, Landuse planning, Public Education,
Public Information, Research and Development, and Institutional Development
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.
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.
Capacity development and enhancement
Review of relationship with related agencies
Lack of a database on building structures
Vulnerability assessment of communities
Obtaining political support
Acknowledgement
This presentation was prepared with support
from the following graduate students: Candice
Ramkisson, Gabrielle Thongs, Roxanne
Smith, and Alicia Jackman
Thank you