1. Why don’t we do
better at
assessing &
mitigating
natural hazards?
How can we
train new
researchers to
do better?

2. Society is playing a high-stakes game of chance
against nature in a very uncertain world
We want to
- assess the hazard - how often dangerous events happen
& how large they will be
- mitigate or reduce the risk - the resulting losses.
Despite steady advances in hazard science & engineering
Often nature surprises us, when an earthquake, hurricane, or
flood is bigger or has greater effects than expected from hazard
assessments.
In other cases, nature outsmarts us, doing great damage despite
expensive mitigation measures, or making us divert resources to
address a minor hazard.

3. Much of the problem comes from the fact that
formulating effective natural hazard policy
involves using a complicated combination of
science, engineering, and social science to
analyze a problem and explore the costs and
benefits of different options, in situations
where the future is very uncertain.
However, we don’t educate students to take
holistic approaches.

4. Our educational system treat the relevant geoscience,
engineering, economics, and policy formulation separately.
Geoscientists generally focus on using science to assess
hazards, engineers and planners focus on mitigation
approaches, and economists focus on costs and benefits.
Each group often focuses on its aspect of the problem,
does not fully appreciate how the others think, what they
know, and what they do not.
This situation often leads to policies that make little
scientific or economic sense. Hazard assessments often
underestimate the limits of scientific knowledge. Mitigation
policies are often developed without considering their
costs and benefits. The net result is that communities
often overprepare for some hazards and underprepare for
others.

5. NY Times 11/2/2011
Choosing policy
involves politics &
economics as well
as science
Too expensive to
rebuild for 2011 sized
tsunami
>100 $B for new
defences only slightly
higher than old ones
“In 30 years there
might be nothing left
there but fancy
breakwaters and
empty houses.”
Less expensive
strategies (land use
& warning systems)
probably better

7. This book is designed for young researchers who would like
to do a better at mitigating hazards, both by advancing the
relevant disciplines and integrating their knowledge and
methods. It is written assuming readers have diverse
backgrounds in geoscience, engineering, economics, and
policy studies.
We use the Tohoku earthquake to illustrate some key
issues, and then introduce some basic concepts to help
readers appreciate the value of the other disciplines and
their interrelations, and to have the background to explore
more advanced treatments of these topics. We explore
aspects of what we know, what we do not know, what
mitigation approaches are available, and how we can chose
between them. Although we primarily use earthquakes and
tsunamis as examples, most of these points apply for other
natural hazards.

8. We explore tough and thought-provoking
questions about complex issues
involved
These topics are challenging for
students because they are far from
normal experience, involve rare events
and large sums, and have no unique or
right answers.

9. CQ:
Estimate the order of
magnitude - 1, 10,
100, or 1000 - of the
number of deaths per
year in the U.S.
caused by bears,
sharks, bees, snakes,
deer, horses, and
dogs.
A good way is to put
them in the relative
order you expect, and
then try to estimate
numerical values.
Lecture 1 9

10. CQ: Do you wear a bicycle helmet?
Why or why not?

11. What can we say about when’s the next
earthquake?
Sieh et al., 1989
M>7 mean 132 yr s 105 yr
Estimated probability in 30 yrs 7-51%
1857 + 132 = 1989, hasn’t happened yet
Earthquake history
from paleoseismology

12. How much mitigation is enough?
Societally optimal level minimizes
total cost = sum of mitigation cost + expected loss
Expected loss = Σ (loss in ith expected event
x assumed probability of that event)
For earthquake, mitigation level is construction code
Loss depends on earthquake & mitigation level
Compared to optimum
Less mitigation decreases
construction costs but increases
expected loss and thus total cost
More mitigation gives less
expected loss but higher total cost
Optimum
Stein & Stein, 2012

13. CQ: If you were a student in Los Angeles, how much
more would you pay in rent each month to live in an
earthquake-safe building?

14. Retrofitting California Hospitals
Following hospital collapses in 1971 San Fernando earthquake
that caused ~50 deaths, California required seismic retrofits
Law assumed retrofits would be cheap
Retrofit cost close to that of new buildings
At least $24 B needed
No funding provided
After 40+ years, slow progress
Deadlines already extended
Won’t be done before at least 2030
CQ: How many lives might this save? Do you think
this this a wise use of resources relative to patient
care? If so, how should it be funded?

15. Risk
communication
Ike
predicted to
bring certain
death
P(death)=1
Lecture 5 15

16. Actual
deaths:
< 50 of
40,000
Error
800x
Credibility
lost

17. CQ: Write a short public
statement - less than 200
words - that you would
have given to the public if
you had been working for
the National Weather
Service as Hurricane Ike
approached Galveston
Island. Your goal is to
realistically describe the
situation and make
sensible
recommendations.

18. CQ: Write a short public statement - less than 200 words -
that you would have given to the public if you had been
working for the Italian civil protection authorities during the
L'Aquila earthquake swarm. Given the public concern that a
large earthquake may occur soon, your goal is to realistically
describe the situation. What would you say when people ask
what they should do?

19. “This is truly an amazing book! The product of a unique
collaboration between a renowned economist and
renowned seismologist (who happen to be father and son),
Playing against Nature lays out a clear story, in easy-to-read
prose, of what natural disasters are, what the
limitations of risk prediction can be, and how society’s
response to them has to account for the reality that we have
limited economic resources. This is a book that researchers,
policy makers, and the general public should read. It can
even serve as valuable text for the new generation of
interdisciplinary college courses addressing the interface
between science and social science.”
– Stephen Marshak, Professor and Director of the School of
Earth Society and Environment, University of Illinois at
Urbana-Champaign

20. “Playing against Nature is a virtuoso performance
by a father-son duo. A distinguished economist
and seismologist have produced a pioneering
work that promises to enhance our ability to
integrate assessment science, cost-benefit
analysis and mitigation design and engineering.
The result will be more informed, bottom-up,
hazard mitigation policies. This outstandingly
researched book is highly readable and destined
to become a classic.”
Steve H. Hanke, Professor of Applied Economics,
The Johns Hopkins University

21. “I very highly recommend this book for anyone dealing with
or interested in natural hazards assessment and mitigation.
It is both highly technical with all the probability and
statistics formulations needed to express necessary
relationships but on the other hand, so well written that
professionals in government, business, and education will
find it exceedingly readable. In my everyday work
experience, I attempt to communicate principles of hazard
occurrences and risks. This book gives me far more useable
material than I have ever had to achieve my goals for
advising public officials, teaching university students, and
educating citizens. This is the best resource in existence for
understanding natural hazards and hazard mitigation.”
James C. Cobb, State Geologist and Director, Kentucky
Geological Survey, University of Kentucky