Workshop and Work Group Program/Programmatic Overview By the California Probabilistic Tsunami Hazard Analysis Work Group

Project Work Plan CGS has developed a panel of experts (Work Group) to review the PTHA methods and products of Principle Investigators (PIs) at URS and the University of Washington, in the following specific areas: 1.tsunami sources/deformation models, 2.PTHA methods, 3.modeling/mapping accuracy, and, 4.applications and appropriate risk level production. The outcomes of a review of the methods and a PTHA workshop will help validate the methods, formulate a plan for map production in California by CGS, and document procedures to be used in the rest of the nation through the National Tsunami Hazard Mitigation Program (NTHMP). CGS has also invited members NTHMP Mapping and Modeling Subcommittee to assist in the review of the PTHA methods.

 Evacuation/Emergency response planning  Maritime planning  Land-use/Mitigation planning

Tsunami Land-Use Planning and Site Evaluation Concern over misuse of deterministic tsunami inundation maps for land-use decision making California Seismic Hazard Mapping Act of 1990 (for residential/business construction) Primarily for liquefaction and seismically induced landslides “Zones of Required Investigation” initiates site- specific evaluation and real estate disclosure If hazard exists, mitigate prior to construction/development 1992 – added tsunami hazard to CA-SHMA; produce PTHA maps when funding and ability to produce maps exists

1980s – Prob. Seismic Hazard Analysis 1990 – Seismic Hazard Mapping Act [ – Seaside, Oregon PTHA study] 2009 – NTHMP funding proposal for CGS to develop maps 2010 – CA-PTHA – work initiated Developed paleotsunami/paleoseismic deposit DB Coordinated with URS/Caltrans/PEER who had initiated PTHA in CA Held first CA-PTHA workshop with PEER on methods Pilot Studies developed: Crescent City (low vulnerability, high hazard) Huntington Beach (high vulnerability, low/moderate hazard) URS completes Year One modeling – Distant sources 2011 – CA-PTHA – work continued Developed Crescent City as pilot comparison between URS and Univ. of WA methods Established CA Tsunami Policy Work Group to bridge to applications NTHMP finalized tsunami hazard modeling/mapping guidance and held model validation workshop Held second CA-PTHA workshop with PEER on Cascadia and Aleutians sources PTHA – Development in CA Crescent City Huntington Beach

Established CA-PTHA Work Group for: Sources Map accuracy/DEMs Methodology Application/Policy Review and compare first-generation results and reports from URS and Univ. of WA Held six teleconference/webex meetings Determine probabilistic risk levels (average return periods) based on applications Develop second-generation maps/products, intended to including: f low depth, velocity, inundation, time series, momentum flux Projected state-wide map completion 2014 Assist with national guidance for PTHA production*** *** Outcome of July 25-27, 2012 NTHMP workshop and Mapping and Modeling Subcommittee meeting PTHA - On-going and Planned Work in CA URS Consultants, 2012 for USGS Science Application for Risk Reduction Program Problem with DEMs/modeling/mapping with overtopping of river levees because of inadequate resolution for map production

California PTHAs – Pilots for NTHMP/Nation July 2012 – Presentations made at NTHMP Hazard/Risk Analysis Workshop in Seattle NTHMP Mapping and Modeling Subcommittee recommended 1.California approach should be “pilot” for NTHMP 2.MMS produce standards/guidance for PTHA production 3.Include these provisions for PTHA and land-use planning products in new Strategic/Implementation Plan February 2013 – discussed at NTHMP meeting PTHA activities included in 2013 Strategic/ Implementation Plans PTHA guidance to be developed by NTHMP in Production continued to be supported by NTHMP and/or multiple other partners (see “Applications”)

Land-Use and other uses for Probabilistic Tsunami Hazard Analysis Our concept: Single set of risk maps for multiple uses › Land-use planning (CA-Seismic Hazard Mapping Act) › Real estate disclosure (CA-SHMA) › Standardized hazard analysis for evacuation planning (CalEMA) › Building design and construction (ASCE, UBC/IBC) › Construction of special critical facilities, like NPPs (NRC) › Flood protection and insurance (FEMA, Risk MAP, CA-DWR) › Input for consistent risk analysis and damage estimates (HAZUS) P R E L I M I N A R Y 2013 URS Consultants, 2013 for Caltrans/PEER/CGS Probabilistic Tsunami Hazard Analysis in Crescent City; blue line is 2009 state inundation map line

Compare methods and products Discuss key elements related to: source characterization PTHA methods modeling inputs and mapping products various applications for PTHA Produce report summarizing results Develop national strategy for PTHA development and use Goals/Outcomes of PTHA Workshop and Work Group Risk levels (ARP) Annual rate of exceedance Seismic Hazard Map Act Zones FEMA FIRM Evacuation planning Evacuation design DWR Flood ZonesASCE - IBC 10050% in 50yr yes in a future version 20025% in 50yr yes 50010% in 50yr yes 10005% in 50yr maybe 25002% in 50yr maybeyes ASCE 7-16; IBC % in 50yr maybe Identify where consensus/ differences in Work Group exists Identify (immediate) issues to be resolved Identify where immediate improvements can be made in PTHA Identify where long-term needs exist for improving PTHA Potential applications for PTHA products and associated risk levels for use

Agenda for Workshop