The document discusses ongoing work by the California Geological Survey and partners to develop probabilistic tsunami hazard analysis and its applications to public policy. It describes initial findings from pilot studies in Crescent City and Huntington Beach, including that probabilistic analysis can improve understanding of tsunami risk if input parameters and uncertainties are well understood. The California Tsunami Policy Working Group is also discussed, which aims to provide guidance on issues preventing full implementation of tsunami hazard mitigation.

1. Rick Wilson, California Geological Survey
Probabilistic Tsunami Hazard
Analysis and Public Policy
Partners =

2. Community

3.  Evacuation/Emergency
response planning
 Maritime planning
 Land-use planning
 Recovery planning
www.tsunami.ca.gov

4.  California Seismic Hazard Mapping Act:
Project–level assessment and real-estate
disclosure
 Expert Work Group assisting in review of pilot
study work in Crescent City and Huntington
Beach
 Initial probabilistic modeling completed by URS
Corp. and Univ. of Washington in parts of
California
 Initial findings completed and report being
generated
 Guidance on application will come from
California Tsunami Policy Work Group
 A second phase of work and mapping is being
initiated
Status of Probabilistic/Land-use Mapping in CA
Crescent City
Huntington Beach

5. Initial Findings of CA-PTHA Work Group
 PTHA in California scientifically feasible
and appropriate for use
 Tsunami model and map results are most
sensitive to source characterization,
especially fault slip/uplift amount
 Alignment with formal Probabilistic
Seismic Hazard Analysis vital, especially
for national production of consistent
products (building code, policymakers,
and NTHMP)
 Application of probabilistic analysis will
improve the understanding of the tsunami
risk, as long as:
 input parameters are correct
 uncertainties are well understood and
translatable
 products are accurate, consistent, and
easy to understand
P R E L I M I N A R Y
URS Consultants, 2012 for
Caltrans/PEER/CGS
Probabilistic Tsunami Hazard
Analysis in Crescent City; blue line
is 2009 state inundation map line

6. Uses for Probabilistic Tsunami Hazard Analysis
Our concept: Produce single set of risk maps/products for multiple uses
› Project–level assessment and real-
estate disclosure (CGS-Seismic Hazard
Mapping Act)
› Land-use planning (communities, CA
Coastal Commission)
› Standardized hazard analysis for
evacuation planning (Cal-OES)
› Building design and construction
, critical facilities (ASCE, Uniform/
International Building Code, Nuclear
Regulatory Commission)
› Flood protection and insurance
(FEMA, Risk MAP, CA-Dept. of Water
Resources)
› Input for consistent risk analysis and
damage estimates (HAZUS)
Preliminary risk levels for different applications
Preliminary products for different applications

7. PILOT STUDIES
•Probabilistic Hazard
•Community Analysis
•Maritime Products
Implementation
TSUNAMI
SCENARIO
•Vulnerability Analysis
•Social & Economic
•Structural Damage
Impact
POLICY WORKING
GROUP
•Land Use – Construction
•Emergency Management
•Recovery
Issues
POLICY MAKERS
Guidance - Regulations
• Local
• State
• Federal
Action
(Soft) (Hard)
 Formed in October 2011 to address issues for
both the state tsunami program and the USGS
tsunami scenario project called “Science
Applications for Risk Reduction” (SAFRR)
 Work Group is a voluntary advisory board
comprised of state, federal, and local
government representatives, as well as private
organizations with interest in coastal planning
 Charged with identifying, evaluating and
making recommendations to resolve issues
preventing full and effective implementation of
tsunami hazard mitigation and risk reduction at
a local level
 Work Group has evaluated the status of
tsunami hazard assessment, preparedness,
mitigation, response, and recovery activities in
the state and identified the needs to sustain
existing programs or implement new programs
California Tsunami Policy Work Group
Figure from Real and others, 2012

8. California Tsunami Policy Work Group
Notable Federal and State Legislation and Programs
(from Johnson and Real, 2013)
FEDERAL LEGISLATION
 Tsunami Warning and Education Act of 2006
(preparedness and mitigation)
 Coastal Zone Management Act of 1972 (planning)
 Disaster Mitigation Act of 2000 (mitigation)
 Stafford Disaster Relief and Emergency
Assistance Act (mitigation and recovery)
STATE PROGRAMS
 California Tsunami Preparedness and Hazard
Mitigation Program (hazard assessment,
preparedness, mitigation, response)
 California Tsunami Policy Work Group (policy
and planning)
 Safety Element in Local General Plans
(planning)
 California Coastal Commission (planning)
 California Building Standards Code
(mitigation)
FEDERAL PROGRAMS
 National Tsunami Hazard Mitigation Program
(preparedness, mitigation, response)
 TsunamiReady Program (preparedness)
 National Response Framework (response)
 National Disaster Recovery Framework (recovery)
 FEMA Flood Insurance Rate Maps and RiskMAP
(mitigation and recovery)
STATE LEGISLATION
 Seismic Hazard Mapping Act of 1990
(mitigation)
 California Coastal Act of 1976 (mitigation and
planning)
 California Oil Spill Prevention and Response
Act of 1990 (recovery – environmental)
NOTE: Tsunami specific in red

9. California Tsunami Policy Work Group
Possible Courses of Action
(from Johnson and Real, 2013)
 Ensure continued funding and support for the National Tsunami Hazard Mitigation
Program, TsunamiReady and affiliated state and local programs.
 Develop a coordinated and sufficiently robust policy framework for tsunami hazard
assessment and mitigation planning for California coastal communities, ports and harbors.
 Explore opportunities to advance multi-hazard mitigation planning along California’s coast
and bays to more holistically address issues of future tsunami risk, sea level rise and
future coastal flooding and erosion, and earthquake-induced liquefaction.
 Encourage responders and government managers at all levels to conduct self-
assessments, devise table-top exercises, and more carefully consider how the short-fuse
intensity and wide geographic scale of tsunami scenarios could challenge current
assumptions.
 Work to address recovery challenges likely for the most vulnerable coastal communities,
ports and harbors, as well portions of the state’s fishing and agriculture sectors.

10. Transferability of Ideas/Policies
Hazard
Assessment
Preparedness
Mitigation
Response
Recovery
Is commitment to pre-
disaster planning for
post-event recovery in
California and U.S.
adequate?
DisasterCycle
Reconstruction Design Council in Response to the
Great East Japan Earthquake, June 2011
Sendai Plain
Santa Cruz