$100M seismic retrofit of Memphis VA hospital, removing nine floors, bringing it to California stand

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USING WHAT WE KNOW AND DONT IN EARTHQUAKE HAZARD
MITIGATION Mitigating risks from earthquakes or
other natural disasters involves economic
policy issues as well as the scientific one of
estimating the hazard and the engineering one of
designing safe structures.

100M seismic retrofit of Memphis VA hospital,
removing nine floors, bringing it to California
standard Does this make sense? How can we help
society decide?
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THOUGHT EXPERIMENT TRADEOFF Your department is
about to build a new building. The more seismic
safety you want, the more it will cost. You have
to decide how much of the construction budget to
put into safety. Spending more makes you better
off in a future large earthquake. However, youre
worse off in the intervening years, because that
money isn't available for office and lab space,
equipment, etc. Deciding what to do involves
cost-benefit analysis. You try to estimate the
maximum shaking expected during the building's
life, and the level of damage you will accept.
You consider a range of scenarios involving
different costs for safety and different benefits
in damage reduction. You weigh these, accepting
that your estimates for the future have
considerable uncertainties, and somehow decide on
a balance between cost
and benefit.
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• THIS PROCESS, WHICH SOCIETY FACES IN PREPARING
  FOR EARTHQUAKES, ILLUSTRATES TWO PRINCIPLES
• There's no free lunch
• Resources used for one goal arent
  available for another, also desirable, one. In
  the public sector there are direct tradeoffs.
  Funds spent strengthening schools arent
  available to hire teachers, upgrading hospitals
  may mean covering fewer uninsured (1 K/yr),
  stronger bridges may result in hiring fewer
  police and fire fighters (50 K/yr), etc...
• There's no such thing as other people's money
• Costs are ultimately borne by society as a
  whole. Imposing costs on the private sector
  affects everyone via reduced economic activity (a
  few cost increase may decide whether a building
  isnt built or build elsewhere), job loss (or
  reduced growth), and the resulting reduction in
  tax revenue and thus social services.

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SCIENCE/ENGINEERING AND ECONOMIC/POLICY ISSUES
ARE INTERRELATED NO SHARP DIVISION BETWEEN THEM
e.g., definition of hazard (number of
years/probability over which to plan for maximum
shaking)
is economic/policy
based Need to view these in holistic way to
formulate sensible policy Challenge is to
develop sensible policies that balance costs and
benefits, given what we know and don't know about
future earthquakes and their effects. Several
approaches can help seismologists and engineers
most usefully contribute.
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• RECOGNIZE THAT THERE ARE NO UNIQUE OR CORRECT
  STRATEGIES, SO SOCIETY HAS TO MAKE TOUGH CHOICES.
  
• Use what we know about earthquake hazards and
  recurrence to help society decide how much to
  accept in additional costs to reduce both the
  direct and indirect costs of future earthquakes.
• Need detailed analysis, which we don't have
  yet, of the costs and benefits of various
  policies.
• Strategy chosen shouldn't be a
  bureaucratic decision imposed from above, but one
  made openly through the democratic process on the
  community level - where costs and benefits of the
  policy accrue.

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SHOULD BUILDINGS IN MEMPHIS MEET CALIFORNIA
STANDARD?
New building code IBC 2000, urged by FEMA, would
raise to California level ( UBC 4) Essentially
no analysis of costs benefits of new code
Year
Code
J. Tomasello
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INITIAL COST/BENEFIT ESTIMATES MEMPHIS AREA I
Present value FEMA estimate of annual earthquake
loss 17 million/yr, part of which would be
eliminated by new code, 1 of annual
construction costs (2 B). II
Life-of-building Use FEMA estimate to infer
annual fractional loss in building value from
earthquakes. If loss halved by new code, than
over 50 yr code saves 1 of building value. If
seismic mitigation cost increase for new
buildings with IBC 2000 gtgt 1, probably wouldn't
make sense. Similar results likely from
sophisticated study including variations in
structures, increase in earthquake resistance
with time as more structures meet code, interest
rates, retrofits, disruption costs, etc.

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2) THOUGHTFULLY ADDRESS LIFE SAFETY U.S.
earthquake risk primarily to property annualized
losses estimated at 4 billion. Also 10
deaths/yr, averaged over larger numbers in major
earthquakes. Annual fatalities roughly constant
since 1800, presumably in part because population
growth in hazardous areas offset by safer
construction. Situation could likely be
maintained or improved by strengthening building
codes, so the issue is how to balance this
benefit with alternative uses of resources (flu
shots, defibrillators, highway upgrades, etc.)
that might save more lives for less. Estimated
cost to save life (in U.S.) varies in other
applications 50 K highway improvements 100 K
medical screening 5 M auto tire pressure
sensors Different strategies likely make sense
in different areas within the U.S. and elsewhere,
depending on earthquake risk, current building
codes, and alternative demands for resources.
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Hence seismic mitigation costs in Memphis area -
20-200 M/yr (1-10 new construction cost) any
retrofits - could insure 20,000 - 200,000 people
and save some lives that way Tricky tradeoff here
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3) EXPLICITLY DISCUSS UNCERTAINTIES We know a
lot less than we'd like about earthquake
recurrence and hazards. Although we hope to do
better, we don't know if we can, given the
complexity shown by long earthquake records and
the growing suspicion that earthquake occurrence
has a large random component. We don't know
whether to view earthquake recurrence as
time-dependent or independent, or even whether
earthquakes are less likely in recently active
areas (Swafford et al, Thurs. AM). Hopefully on
some time scale, perhaps a few hundred years, we
will have made and tested forecasts adequately to
have reasonable confidence in them. Until then,
we should explain what we know and what we don't.
There's no harm in discussing the limits of
what we know. Individuals and society make
decisions given uncertainty we buy life
insurance and decide how much to spend on safety
features in cars. Business and political leaders
consider risks in deciding whether and how to
invest. In fact, we help ourselves by explaining
what we don't know, since we want public funds to
learn more.
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UNCERTAINTIES IN NMSZ HAZARD MAPS

Areas of predicted significant hazard differ
significantly, depending on poorly known
parameters. Differences have major policy
implications (e.g. Memphis St.
Louis). Uncertainties wont be resolved for
100s-1000s years Uncertainties dominated by
systematic errors (epistemic) and hence likely
underestimated
Newman et al., 2001
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4) AVOID BIASING HAZARD ESTIMATES Estimates
biased toward high ("conservative") values
distort policy decisions by favoring seismic
safety over other resource uses. Dont want
poor education in earthquake-safe schools, or to
turn away patients from earthquake-safe
hospitals Need careful balance An analogy might
be the tendency during the Cold War to
overestimate Soviet military power, leaving the
U.S. with enormous military strength but
diverting resources from health, education, and
other societal goals.
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5) HAZARD ASSESSMENTS AND MITIGATION POLICIES
SHOULD UNDERGO DISINTERESTED PEER REVIEW Crucial
economic and societal issues should fully
explored before a decision. For example,
arguments used to infer that the New Madrid zone
is as hazardous as California should have been
carefully analyzed, given their enormous cost
implications. These result largely from
redefining the hazard from the largest earthquake
expected every 500 years to that expected every
2500 years.
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EFFECT OF 2500 YEAR CRITERION - MUCH LONGER THAN
ORDINARY BUILDING LIFE

Considers maximum shaking at a geographic point
over 500 or 2,500 yr (10 or 2 in 50 yr) while
neglecting much shorter life of ordinary
structures. Definition allows New Madrid hazard
to be similar to that in California, although
annual California hazard is much lower. By
similar argument, in very long (three million
hand) poker game. probability of at least one
pair and royal flush are comparable - although
in one hand, the probability of a pair is 43,
whereas that of a royal flush is far less, 1 /
100,000 Using this argument would lose money in
ordinary duration game.

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6) TAKE TIME TO GET THINGS RIGHT Because major
earthquakes in a given area are infrequent on
human timescale, we generally have time to
formulate strategy carefully (no need to
rush to wrong answer) Time can also help on both
the cost and benefit sides. As older buildings
replaced by ones meeting newer standards, overall
earthquake resistance increases. Similarly, even
where retrofitting isn't cost-effective, higher
standards for new ones may be. Technological
advances can make additional mitigation cheaper
and more cost-effective. If understanding of
earthquake probabilities becomes sufficient to
confidentially identify how probabilities vary
with time, construction standards could be
adjusted accordingly where appropriate.
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7) WE ARE NOT ALONE There's increasing interest
in making mitigation policy more rationally for
other hazards with considerable uncertainties.
The direct costs of federal environmental,
health, and safety regulations are probably 200
billion annually, about the size of all federal
domestic, nondefense discretionary spending. The
benefits of those regulations are even less
certain. Evidence suggests that some recent
regulations would pass a benefit-cost test while
others would not. (Brookings Institution
American Enterprise Institute) Viewing
seismology and engineering as part of a holistic
approach to hazards mitigation will make our
contributions more useful to society. This
utility will grow as we learn more about
earthquakes and their effects in different areas.