Earthquake Quarterly - Winter 1998

 

Table of Contents

Use of Earthquake Scenarios to Cope
with Post-earthquake Disruptions
by James F. Davis

Capital Regional District Earthquake
Hazard Mapping Project: Victoria, British Columbia
by Victor M. Levson and Patrick Monahan

New Developments in National Earthquake
Loss Estimation Modeling
by Gil Jamieson

WSSPC Policy Recommendations

WSSPC Board Corner

Annual Conference - Wrap-Up

The Western States Seismic Policy Council (WSSPC) held its 1997 Annual Conference in Victoria, British Columbia on November 4-7. Delegates from member states attended, including several state geologists and emergency management directors. The conference focused on seismic policy (see related article below), and included policy sessions on Building Codes and Seismic Zonation, Hazard Loss Estimation and Scenario Development, and Earthquake and Hazard Insurance.

The conference also highlighted the recipients of the WSSPC Awards in Excellence. At the conference banquet,, recognizing a variety of programs, awards were presented to agency representatives at the conference banquet. The following day, presentations were made describing these programs and their implementation. As a follow-up to the conference, WSSPC has produced a volume describing the Awards in Excellence programs. Limited quantities of this volume are available by contacting the WSSPC office.

In an effort to add value to the conference, WSSPC published a Policy Session Papers volume. The papers from the session speakers were compiled and distributed to all attendees, before the conference. Limited quantities of this volume are also available.

In this issue of EQ we included a summary of some of the policy session papers. The three papers are from the Hazard Loss Estimation and Scenario Development session. Future issues of EQ will focus on the other two policy session topics. In the Spring EQ, building codes will be featured and in the Summer EQ, hazard insurance will be featured.

^ BACK TO TABLE OF CONTENTS

Use of Earthquake Scenarios to Cope with Post-earthquake Disruptions *

James F. Davis

Department of Conservation

Division of Mines and Geology

Post-earthquake disruption can be separated into two phases based on the length of time following damaging events. During the first 72 hours or so, emergency response efforts to provide medical aid, conduct search and rescue and to limit access to unsafe structures are high priority activities. As these efforts are achieved, emergency response activities transition into recovery operations that may extend beyond the first twelve months. Recovery includes repair or replacement of lifeline infrastructures and damaged buildings and economic assistance provided to earthquake victims through insurance and public sources such as the Disaster Relief and Emergency Assistance Act administered through state government by FEMA.

Emergency Response:
Effective emergency response depends upon pre-event planning and rapid assessment of the circumstances that must be confronted in order to implement existing plans immediately after the earthquake. Insights from assessments of anticipated ground motion and ground failure are crucial to creating plans that consider the plausible impacts from future earthquakes on communities.

Recovery:
Effective recovery is as challenging an effort as emergency response and it is as essential to mitigation of earthquake economic losses. Recovery is facilitated by adequately insuring future losses so that financial resources for replacement and repair of damage are available. Other strategies to reduce the time required to restore community and commercial activities to normal conditions can be envisioned in planning before earthquakes occur.

^ BACK TO TABLE OF CONTENTS

Capital Regional District Earthquake Hazard Mapping Project:

Victoria, British Columbia, Canada *

Victor M. Levson (Ph.D., P.Geo.)

Patrick Monahan (P. Geo.)

Project Overview:
The Earthquake Hazard Mapping project is a multi-year project to map potential earthquake hazards in the main urban and adjoining areas in southwest British Columbia. Earthquake Hazard maps show soil liquefaction, amplification and/or landslide hazards and thus display the relative potential for ground disturbance due to variations in local geologic soil conditions (Levson et al., 1997). They are intended to provide basic data for emergency response, land use and community planning, setting realistic insurance rates and prioritizing seismic retrofitting of public facilities.

Mapping in 1996-97 is focussing on the Capital Regional District (CRD) which is now commencing a Growth Strategies Plan. A principal objective of the British Columbia Growth Strategies Act (Section 942.11[2]) is to ensure that settlement patterns minimize risks associated with natural hazards. Expenditures for seismic retrofitting in the province now exceed $1 billion. Southwest B.C. has the highest earthquake risk in Canada (8 earthquakes greater than magnitude 6.0 in the last 100 years within 300 km of Vancouver). The estimated potential economic impact of an M = 6.5 earthquake on the Lower Mainland alone is $14.3 to $32.1 Billion (Munich Reinsurance, 1992). The British Columbia Geological Survey has conducted a pilot mapping project in the Chilliwack area.

^ BACK TO TABLE OF CONTENTS

New Developments in National Earthquake Loss Estimation Modeling *

Gil Jamieson

Federal Emergency Management Agency

The HAZUS Loss Estimation Methodology was developed to provide local, State and regional officials with the tools necessary to plan and stimulate efforts to reduce risk from earthquakes and to prepare for emergency response and recovery from an earthquake.

HAZUS is also capable of assessing earthquake risk on a national scale and FEMA is currently in the process of preparing an Annualized Earthquake Loss Estimate. This annualized estimate is being done in partnership with the US Geological Survey, and will portray expected annual losses due to earthquakes for each county in the continental United States.

Prior earthquake loss estimates varied in scope, detail, and complexity. Regional variability of databases, including building and lifeline inventories, limited the degree of comparison on a national scale.

Annual losses computed in this study are based on the probabilistic ground shaking hazard curves developed by the USGS for the National Earthquake Hazard Reduction Program Provisions (Frankel et al., 1996).

As results are aggregated to the county and state level, this annual loss estimate will help identify key urban areas for earthquake loss reduction activities and help establish priorities for the intensified collection of earth science data. The capability to create annualized loss estimates will become available in the 1998 HAZUS release.

Providing communities with the basic earth science information necessary of the development of effective mitigation activities and emergency preparedness is one of the goals of the National Earthquake Loss Reduction/Hazard Reduction Program.

Using the Annualized Earthquake Loss Estimate as a starting point, we plan to identify 10 to 20 urban areas in the coterminous US at risk from earthquakes. A provisional list of credible scenario earthquakes will be developed and distributed to the scientific community for review and comment during the next year. Once finalized, this list would itemize the source parameters to be used and discuss the planning events in relatively easy to understand terms. The list of recommended events would be distributed with future updates of HAZUS and would be updated as required.

^ BACK TO TABLE OF CONTENTS

From the Desk of Executive Director

It is with excitement about the activities planned for 1998 that I write to you in this issue of EQ: Earthquake Quarterly. We are now into our second year as an independent non-profit organization. This year WSSPC will host the Western United States Earthquake Insurance Summit from June 25-26 in Sacramento (page 4) with the Council of State Governments-WEST. We are also hosting the 20th WSSPC Annual Conference on September 15-18 in Pasadena, California.

In this issue of EQ we turn inward and showcase WSSPC activities. We have included articles regaring the 1997 WSSPC Annual Conference (front page), Tsunami Hazard Mitigation Symposium (page 8) held in Victoria, British Columbia and the WSSPC Awards in Excellence (page 7). As discussed on the front page, this issue highlights our efforts to adopt policy recommendations that are designed to provide a forum to advance earthquake hazard reduction programs throughout the Western Region and to develop, recommend and present seismic policies and programs through information exchange, research and education.

As mentioned in our last edition we are producing this smaller version of EQ in order to allow us to prepare for production of the full issue this summer. The feature topic of the Spring EQ is building codes. We will look at many aspects of building codes — how to adopt codes, the political realities of codes, grading building code enforcement and the adoption of the unified International Building Code 2000.

^ BACK TO TABLE OF CONTENTS

WSSPC Policy Recommendations

At its annual business meeting on November 7, 1997, the Western States Seismic Policy Council (WSSPC) adopted the following policy recommendations. WSSPC defines seismic policy as government policy that relates to earthquake hazards and mitigation. Later this spring, WSSPC will issue white papers supporting each of these recommendations.
(continued on page 7)

WSSPC PR97-1: Active Fault Definition Categories for the Basin and Range Province

WSSPC recommends that the following guidelines be used in defining active faults in the Basin and Range physiographic province. Active faults can be categorized as follows, recognizing that all degrees of fault activity exist and that it is the prerogative of the user to decide the degree of anticipated risk and what degree of fault activity is considered "dangerous":

1. Holocene Active Fault - a fault that has moved within the last 10,000 years.

2. Late Quaternary Active Fault - a fault that has moved within the last 130,000 years.

3. Quaternary Active Fault - a fault that has moved within the last 1,600,000 years.

It should be emphasized that more than half of the historic magnitude 6.5 or greater earthquakes in the Basin and Range province have occurred on faults that did not have Holocene activity, furthermore, earthquakes in the province will occur on faults in all three categories.

WSSPC PR97-2: Developing Guidelines for Fault Trace Setbacks

WSSPC encourages individual state workshops to develop guidelines for local jurisdictions to establish consistent criteria for setbacks from surface traces of one or more categories of active faults, such as those defined in WSSPC PR97-1. In several western states, policy for the regulation of setbacks from active surface fault traces is established at the local level. WSSPC encourages individual jurisdictions that are traversed by the same active fault to have consistent setback requirements. Note that setbacks deal with surface fault ruptures from earthquakes, but do not address the broader, more significant hazards of ground shaking and other effects, such as ground-motion amplification, liquefaction, rockfalls, and landslides.

WSSPC PR97-3: Development of National Earthquake Hazard Risk Mitigation Priorities

WSSPC proposes to take the initiative to coordinate a process with the federal NEHRP agencies and regional earthquake consortia to establish national earthquake hazard risk mitigation priorities. This may be accomplished by WSSPC facilitating dialog among the states and presentation of consensus to the federal government.

WSSPC PR97-4: Seismic Monitoring Networks

Because seismic monitoring networks are vital for earthquake hazard characterization and because there is an insufficiency in available data, WSSPC advocates the continuation and expansion of seismic monitoring networks, including strong motion instrumentation, by support from state and federal agencies. WSSPC further recommends existing networks be interconnected by compatible hardware and software.

^ BACK TO TABLE OF CONTENTS

WSSPC Board Corner

The WSSPC Board of Directors is holding their March meeting in Washington, DC. Immediately following the American Association of State Geologists, the Board will have a full agenda to address. Their agenda includes planning the upcoming WSSPC events, as well as a new proposal to create an internet-based teamware environment for our members. The Board will also be meeting with John Filson of the United States Geological Survey and representatives of the Federal Emergency Management Agency.

WSSPC Audit: WSSPC just completed the review of its first year’s financial records. The accounting firm of Eckhoff Accountancy Corporation, has certified our records. A full financial report will be provided in the soon-to-be published WSSPC Annual Report.

WSSPC’s Additions: We welcome the newest additions to the WSSPC community. WSSPC hired a new Program Manager, Ms. Theresa Traynor, to replace Ms. Andrea James. Ms. Traynor comes from a strong background in working with non-profits and will be an excellent addition to our team.

Also, we welcome George Crawford as the new Earthquake Program Coordinator for the Washington State Emergency Management Division and Susan Walker as the new Earthquake Program Manager for the New Mexico State and Local Preparedness Bureau.

Lastly, we would like to congratulate and bid a farewell to John Steinmetz. Dr. Steinmetz, State Geologist at the Montana Bureau of Mines and Geology, has served on the WSSPC Board of Directors since its creation. He will be leaving the west to take a position as the next Director of the Indiana Geological Survey and State Geologist of Indiana. Thank you for your years of dedicated service.

^ BACK TO TABLE OF CONTENTS