Table Of ContentLIVING IN LAHAR ZONES: ASSESSING HAZARD EXPOSURE, RISK
PERCEPTION, AND PREPAREDNESS BEHAVIORS IN COMMUNITIES
WITHIN THE MOUNT BAKER AND GLACIER PEAK VOLCANIC
HAZARD ZONES
by
Kimberley Anne Corwin
A thesis
submitted in partial fulfillmen t
of the requirements for the degree o f
Master of Science in Geology
Boise State University
August 2016
© 2016
Kimberley Anne Corwin
ALL RIGHTS RESERVED
BOISE STATE UNIVERSITY GRADUATE COLLEGE
DEFENSE COMMITTEE AND FINAL READING APPROVALS
of the thesis submitted by
Kimberley Anne Corwin
Thesis Title: Living in Lahar Zones: Assessing Hazard Exposure, Risk Perception,
and Preparedness Behaviors in Communities within the Mount Baker
and Glacier Peak Volcanic Hazard Zones
Date of Final Oral Examination: 2 December 2015
The following individuals read and discussed the thesis submitted by student Kimberley
Anne Corwin, and they evaluated her presentation and response to questions during the
final oral examination. They found that the student passed the final oral examination.
Brittany D. Brand, Ph.D. Chair, Supervisory Committee
Monica Hubbard, Ph.D. Member, Supervisory Committee
Thomas Wuerzer, Ph.D. Member, Supervisory Committee
Jeffrey B. Johnson, Ph.D. Member, Supervisory Committee
The final reading appro val of the thesis was granted by Brittany D. Brand, Ph.D., Chair
of the Supervisory Committee. The thesis was approved for the Graduate College by
Jodi Chilson, M.F.A., Coordinator of Theses and Dissertations .
DEDICATION
I would like to dedicate this thesis to a woman whose hard work, dedication,
perseverance, and independence I have always admired and aspired to imitate. Always
telling me that I can do whatever my heart desires, encouraging my interests, and
supporting my geology adventures from Cape Cod to New Zealand to Chile and Boise.
For being my best role model and a source of unending encouragement, this thesis is
dedicated to my mother Karen Anne Brown.
I would also like to dedicate this thesis to two incredible female scientists: Dr.
Brittany Brand (my thesis advisor) and Dr. Britt Argow (my undergraduate advisor). You
have both been great inspirations to me as scientists and women in science.
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ACKNOWLEDGEMENTS
I would like to thank Dr. Brittany Brand for providing the opportunity to work on
a truly interdisciplinary and inspiring project, for pushing me to work harder and stretch
my abilities further, and for providing invaluable advice throughout this process. Thank
you for going on this non-traditional journey with me and supporting me through all the
bumps in the road.
I would also like to thank my supervisory committee Dr. Monica Hubbard,
Dr. Thomas Wuerzer, and Dr. Jeffrey Johnson for providing me with excellent advice and
direction. Your careful scrutiny has helped refine this work and ensured the publication
of a strong and comprehensive final product. I would also like to acknowledge Joshua
Hewitt for providing statistical advice. Thank you to Dr. David Johnston (and team), John
Schelling (Washington State Emergency Management Division), the Skagit County
Emergency Management, and the Cascade Volcano Observatory for assisting in the
design and distribution of my survey and for providing advice throughout the thesis
process. Finally, thank you to the Boise State University Geosciences Department for
embracing such a unique and interdisciplinary research project and for funding this
research with the department’s Burnham Grant .
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ABSTRACT
As the number of people living at risk from volcanic hazards in the U.S. Pacific
Northwest grows, more detailed studies of community hazard exposure, risk perception,
and preparedness levels become critical to developing effective mitigation, response, and
recovery plans. This thesis uses risk mapping and a knowledge, risk perception, and
preparedness survey to examine the risk that lahars from Mount Baker and Glacier Peak
volcanoes pose to nearby communities in the Skagit Valley (WA). The risk map
component of this research identifies spatial variations in lahar risk and estimates
potential losses associated with a maximum envisioned lahar. The survey component
seeks to (1) explore the existence of a disconnect between accurate risk perception and
adequate preparedness; (2) isolate the factors that facilitate or present barriers to the
adoption of preparedness behaviors; and (3) determine how professional participation in
hazard risk management influences knowledge, risk perception, and preparedness in the
Skagit Valley. Elements of the Protective Motivation Theory (PMT) and Values-Beliefs-
Norms (VBN) theory are used to frame the survey results.
The risk maps generated in this study show that towns with populations smaller
than 1,000 people (e.g., Concrete, Lyman) will likely be disproportionately affected by
lahars, supporting the findings of Diefenbach et al. (2015). Lahar zones intersect large
portions of these smaller towns, including critical roads that link them to nearby towns
and emergency services. Such a loss of infrastructure would greatly reduce response
capacity. Burlington represents one of the most at -risk towns in the Skagit Valley since a
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relatively large population (8,466) lives in this city that is almost entirely in the lahar
zone. In a total loss scenario, the maximum envisioned lahar wou ld place nearly 40,000
lives at risk along with extensive tracts of residential and agricultural land. Overall
monetary damages could amount to over $5 billion (total assessed value) and nearly $62
million in tax revenue. Additional geologic modeling of la har paths would greatly
improve the ability to produce more complex loss scenarios.
Results from over 500 survey responses indicate that a disconnect exists between
perception and preparedness among respondents. The 82 percent of respondents who
accurately anticipate that future volcanic hazards will impact the Skagit Valley fail to
prepare more than those unaware of the hazard . When asked what prevents them from
preparing, respondents deny that perceived response-efficacy and perceived protective
response pose substantial barriers . Perceived self-efficacy and ascription of responsibility
beliefs appear to play a more dominant role in determining preparedness behaviors, albeit
a less readily recognized role . Ascription of responsibility beliefs (VBN) seems to
explain an element of preparedness motivation not fully incorporated within PMT.
Finally, results show that professional participation in response-related activities
minimally influences household preparedness, but successfully improves perceived self -
efficacy, confidence in officials, and information seeking behavior. Thus, participation’s
affect on household preparedness may be tied to specific types of participation (e.g. ,
public, professional, specific training programs), whereas self -efficacy and confidence in
officials, being independent of participation type, may improve due to increased
interaction with emergency officials.
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TABLE OF CONTENTS
DEDICATION ......................................................................................................................... iv
ACKNOWLEDGEMENTS ...................................................................................................... v
ABSTRACT ............................................................................................................................. vi
LIST OF TABLES ................................................................................................................... xi
LIST OF FIGURES ............................................................................................................ xiii
LIST OF ABBREVIATIONS ............................................................................................. .xvi
CHAPTER ONE: INTRODUCTION ..................................................................................... 1
CHAPTER TWO: LITERATURE REVIEW ......................................................................... 6
Risk ........................................................................................................................... .6
The Physical Dimension: Lahar Hazards and Mapping .............................................. 7
An Introduction to Lahars ............................................................................... 7
History of Volcanic Activity at Mount Baker and Glacier Pea k.................... 10
Mapping the Mount Baker and Glacier Peak Lahar Hazard Zone s................ 16
Incorporating the Build Environment: Risk Maps Motivatio n....................... 19
The Human Dimension: Risk Perception and Preparedness Motivatio .n................... 20
Risk Perception Models ................................................................................ 20
Applying Risk Perception Concepts to Natural Hazard .s.............................. .30
Factors Controlling Risk Perception ............................................................. .31
The Risk Perception Paradox and Factors Controlling Preparedness
Actions ......................................................................................................... 39
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Participation: The Solution to the Risk Perception Paradox? ......................... 42
Knowledge Gap and Motivation for Human Dimension of Thesis ................ 43
CHAPTER THREE: LAHAR HAZARD & RISK MAPPING .............................................. 46
Methods....................................................................................................................... 46
Results & Discussion .................................................................................................. 48
CHAPTER FOUR: RISK PERCEPTION & PREPAREDNESS STUDY ............................ 62
Research Summary ..................................................................................................... 62
Methods....................................................................................................................... 63
Questionnaire Development and Content ....................................................... 63
Questionnaire Distribution Procedure ............................................................. 68
Participant Characteristics .............................................................................. 69
Data Analysis .................................................................................................. 70
Measurement Scales........................................................................................ 73
Results ......................................................................................................................... 77
The Disconnect Between Risk Perception, Awareness, and Preparedness .... 77
Barriers to Further Preparedness Behaviors ................................................... 81
Professional Participation’s Influences on Household Preparedness &
Personal Beliefs .............................................................................................. 90
Discussion ................................................................................................................. 100
PMT and Understanding Preparedness Behaviors ........................................ 101
VBN Theory and Understanding Preparedness Behaviors ........................... 107
Professional Participation’s Influence on Household Preparedness &
Personal Beliefs ............................................................................................ 108
Advantages and Disadvantages of Survey Methodology ............................. 112
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Additional Theoretical and Practical Implications ....................................... 113
CHAPTER FIVE: CONCLUSIONS .................................................................................... 117
REFERENCES ..................................................................................................................... 122
APPENDIX A ....................................................................................................................... 133
Survey Questions ...................................................................................................... 133
APPENDIX B ....................................................................................................................... 146
Response Frequencies & Open Response Text ........................................................ 146
APPENDIX C ....................................................................................................................... 167
Survey Postcard Advertisement ................................................................................ 167
APPENDIX D ....................................................................................................................... 169
Barrier Correlations .................................................................................................. 169
APPENDIX E ....................................................................................................................... 179
IRB Approval Letter ................................................................................................. 179
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