OSSPAC Tsunami Report
Total Page:16
File Type:pdf, Size:1020Kb
Tsunami Resilience on the Oregon Coast OSSPAC Publication 21-01 January 12, 2021 For: THE STATE OF OREGON Mike Harryman, State Resilience Officer Tsunami Resilience on the Oregon Coast • January 12, 2021 1 2020 OSSPAC Members: Jeffrey Soulages Chair, Public Member Tiffany Brown Oregon Seismic Safety Policy Advisory Commission Vice-Chair, Local Government Stakeholder After the Loma Prieta earthquake in 1989, Oregon residents Matt Crall demanded that the State of Oregon better address earthquake Department of Land Conservation & Development hazards throughout the state. The state legislature established David Gomberg the Oregon Seismic Safety Policy Advisory Commission (OSSPAC) Representative, Legislative Assembly in 1991 through Senate Bill 96. The Commission is a group of Dacia Grayber eighteen individuals appointed by the Governor. They represent a First Responder Stakeholder variety of interests regarding public policy and earthquakes and Bob Houston include representatives of many state agencies, a member each Department of Geology and Mineral Industries from the Oregon House and Senate, representatives of important Joe Karney stakeholder groups, and members of the public. The OSSPAC Utilities Stakeholder mission is to positively influence decisions and policies regarding Christina LeClerc pre-disaster mitigation of earthquake and tsunami hazards; Oregon Department of Transportation increase public understanding of hazard, risk, exposure and Ed MacMullan vulnerability through education; and be responsive to new studies Banking Stakeholder or issues raised around earthquakes and tsunamis. Bonnie Magura Schools Stakeholder Walter McMonies Multifamily Housing Stakeholder Trent Nagele Structural Engineer Stakeholder Copyright 2021 by the Oregon Seismic Safety Policy Advisory Commission of the State of Oregon. Excerpts from this report, except materials copyrighted by others, may be Adam Pushkas reproduced for non-commercial use with attribution to the Oregon Seismic Safety Policy Building Owners Stakeholder Advisory Commission. Althea Rizzo Oregon Office of Emergency Management Printed in the United States of America Arnie Roblan Senator, Legislative Assembly IBSN # Susan Romanski Public Member OSSPAC Publication Number 21-01 Aeron Teverbaugh Department of Consumer and Business Services Katie Young Public Member Production Assistant: Deb Schueller 2 2020 OSSPAC Members: Jeffrey Soulages Chair, Public Member Tiffany Brown Vice-Chair, Local Government Stakeholder Matt Crall Department of Land Conservation & Development contents David Gomberg Representative, Legislative Assembly preface . ii Dacia Grayber executive summary . .iv First Responder Stakeholder chapter one Bob Houston Early Efforts to Address Tsunami Risk on the Oregon Coast . .1 Department of Geology and Mineral Industries chapter two Joe Karney Utilities Stakeholder Recent Developments and Setbacks . 9 Christina LeClerc chapter three Oregon Department of Transportation Making the Coast More Resilient to Tsunamis . .15 Ed MacMullan Banking Stakeholder chapter four The Future of a Resilient Coast . 25 Bonnie Magura Schools Stakeholder references . .27 Walter McMonies appendix a Multifamily Housing Stakeholder List of Stakeholders . .A1 Trent Nagele Structural Engineer Stakeholder appendix b Glossary of Terms . .B1 Adam Pushkas Building Owners Stakeholder Althea Rizzo Oregon Office of Emergency Management Arnie Roblan Senator, Legislative Assembly Susan Romanski Public Member Aeron Teverbaugh Department of Consumer and Business Services Prepared by: Katie Young Public Member OREGON SEISMIC SAFETY POLICY ADVISORY COMMISSION Tsunami Resilience Working Group Tsunami Resilience on the Oregon Coast • January 12, 2021 i preface In 2019, the Oregon legislature passed HB3309 and Governor Brown signed it into law. The main impact of this legislation was to remove the moratorium established 25 years ago through SB379 on constructing critical buildings on the Oregon coast within the tsunami inundation zone. This change in policy caught many in the emergency management and resilience community by surprise, including those of us serving on the Oregon Seismic Policy Advisory Safety Commission (OSSPAC). The purpose of this report is to review the history of the original SB379 legislation, study the work done by state agencies in assisting coastal communities with tsunami planning, explore recent changes in codes and standards, and recommend a way forward to assure the tsunami safety and resilience of our coastal communities. ii Throughout this report, the term “Cascadia event” is used to represent the Cascadia Subduction Zone earthquake and resulting tsunami. “Tsunami Hazard Overlay Zone” refers to local land use planning regulations that restrict certain uses and require other safety measures within tsunami inundation zones. In gathering input for this report, the Tsunami Working Group of OSSPAC consulted with the State Resilience Officer and engaged other state and local government officials. OSSPAC heard testimony from representatives of non-governmental engineering organizations, code committees, representatives of coastal stakeholders, and members of the public. Included in Appendix A is a list of the testimony received from stakeholders. OSSPAC received support from the Department of Consumer and Business Services (DCBS), especially the Division of Financial Regulation and the Department of Land Conservation and Development (DLCD). OSSPAC gratefully acknowledges the financial support of the Department of Consumer and Business Services, Oregon Department of Geology and Mineral Industry (DOGAMI), and the Office of Emergency Management (OEM). i Jeffrey Soulages Tiffany Brown OSSPAC Chair OSSPAC Vice-Chair Tsunami Resilience on the Oregon Coast • January 12, 2021 iii executive summary In 2020, the Oregon Seismic Safety Policy Advisory Commission (OSSPAC) voted to form a working group to investigate ways to address the tsunami safety and resilience of Oregon’s coastal communities. This was in reaction to the Oregon Legislature passing HB3309 in 2019, which removed the moratorium established 25 years ago on constructing critical buildings on the Oregon coast within the tsunami inundation zone. Through workgroup meetings and stakeholder testimony, OSSPAC investigated the work done by state agencies in aiding coastal communities with tsunami planning, as well as recent changes in building codes and standards. The commission’s major recommendations are as follows: iv Recommendations A. Support and strengthen the use of tsunami overlay zones and evacuation planning by coastal communities in Oregon . The first step to ensuring that coastal communities thrive after a major earthquake is to encourage good land use and evacuation planning. This allows each community to determine for itself what functions are most important, as well as their own level of acceptable risk. Support communities in their efforts to establish Tsunami Hazard Overlay Zones. Encourage the Oregon Department of Land Conservation and Development (DLCD) to continue to assist these communities and support critical projects like future revisions of the Tsunami Land Use Guide. Provide adequate funding to DLCD to support this mission in the form of $250K per biennium for grants directly to communities and a limited duration FTE for providing direct consulting to coastal communities. Work with DLCD, DOGAMI, and OEM to establish robust tsunami evacuation and wayfinding routes. Continue to support coastal community efforts to hold annual tsunami drills to improve evacuation wayfinding. B. Continue to improve tsunami maps for use on the Oregon Coast . Maps and models are the data that inform land use planning, evacuation routes, and structural design. Different maps are required for different purposes. Support mapping efforts to give Oregon the best data on which to base decisions about the future. This includes worst-case maps used for evacuation, other maps for land use planning, and maps for structural design that are compatible with those used to design other hazards. Support DOGAMI’s efforts to develop updated maps for structural design using high-resolution for the best detail of the Oregon coast. The effort should incorporate the latest research in tsunami source characterization and be based on the consensus of experts throughout the nation. These maps should follow the procedures of ASCE 7-16 including surface roughness and nonlinear factors and should be consistent with earthquake inputs to the national earthquake hazard maps of USGS. C. Establish state-wide structural load standards for designing critical buildings in the tsunami zone and vertical evacuation shelters . While land use planning will address many critical structures, it won’t catch them all. Not all coastal communities have a tsunami hazard overlay yet, and even those that do will have certain structures like fire stations that need to be located within the inundation zone in order to meet critical every day response needs. For those situations, a technically based, state-of-the art national consensus procedure for safely designing structures to survive in the tsunami inundation zone is required, and it needs to be applied consistently throughout the entire state. Adopt ASCE 7-16, including the entirety of Chapter 6 and the tsunami design geodatabase for the design of Tsunami Resilience on the Oregon Coast • January 12, 2021 v all Risk Category III and IV structures within the Tsunami Design Zone in the State of Oregon. Re-align the remaining portions