
Tampa Bay’s coming storm - raker_SDF
https://www.washingtonpost.com/graphics/2017/health/environment/tampa-bay-climate-change/?utm_term=.46562afa5dae
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toomuchtodo
Tampa Bay resident here (Brandon suburb really, but close enough).

The reason this happens is simple: other people's money is subsidizing the
losses.

First, Florida is extremely fiscally conservative. Taxes for anything are a
hard sell. Without additional taxes, our infrastructure will continue to lag,
causing far more damage than would've been had we ponied up the taxes in the
first place. Also, infrastructure is not prioritized over glitzy marketing. St
Petersburg is in dire need of a waste water treatment plant upgrade, but it's
mayor is going to spend the money on a development project instead ("The
Pier").

Second, insurance: the state has a high risk pool that you can join as an
insurer of last resort, and they'll insure you across multiple losses. As long
as we continue to issue insurance (taxpayer sponsored!) for properties that
are subject to repeated losses or sea level rise, we'll continue to throw good
money after bad.

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Animats
Switzerland is fiscally conservative. Florida is just low-tax.

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phkahler
the word conservative is not really a synonym for the word responsible.

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mannykannot
As there is a political industry devoted to promoting the idea that it means
exactly that, that's just another reason for replacing it, or at least
challenging its use.

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polotics
I am amazed by the use of the word "conservative" in the interviews, used to
describe the most reckless behaviour.

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rootsudo
I remember reading this, and now this becoming a reality.

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tempodox
Demonstrably not a question of “if”, but “when”.

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njarboe
First line: "The area is due for a major hurricane, ..."

Hurricanes aren't like earthquakes where something builds up over time to make
an event more likely if there has not been one recently. It's like saying "The
roulette wheel is due to hit number 2."

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johnchristopher
I am ignorant in these matters but do earthquakes likely occurrences somehow
build up over time ?

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cossatot
moonka is describing a theory called the 'elastic rebound theory' that has
been the dominant theory of earthquake mechanics since it was proposed by
Harry Reid in 1910 after studying the 1906 San Francisco earthquake. It
basically states that the earth's upper crust is an elastic material, and (as
they said) stress builds as the different sides of the fault move with respect
to one another, but the fault remains 'locked', i.e. it's not slipping,
usually from the surface to 10-20 km depth.

This produces both shear stress (i.e. stress that promotes sliding on the
fault) and normal stress (i.e. stress that resist sliding on the fault due to
friction).

One common manifestation of the elastic rebound theory says that there is some
relatively fixed stress ratio at which the shear stress overcomes the
frictional resistance to slip and the fault slides rapidly in an earthquake.
The basic assumption (which is supported by data for some well-studied faults
such as the San Andreas) is that the rates of strain accumulation are
generally constant through time, and therefore earthquakes on a fault are
quasiperiodic in time and have more or less similar magnitudes. These are
called 'characteristic earthquakes'.

In this situation, then the likelihood of an earthquake on a given part of a
fault does increase with time since the last earthquake. I wrote a blog post
quantifying this for the southern San Andreas Fault [1], using data from the
geologic record and only a few assumptions (basically just that the geologic
record contains all of the earthquakes).

However, though very few researchers disagree with the fundamental principles
of elastic rebound theory, there is an ongoing scientific debate over whether
earthquakes are periodic and characteristic, or more or less random. Many
statistical seismologists believe that they are the common form of 'random',
i.e. that the likelihood of an earthquake doesn't change with time since the
last earthquake. Some faults (and especially larger fault systems) seem to
behave in this fashion, but for an individual fault this implies very
different earthquake physics. There are huge fights in places like California
between senior scientists over this topic when doing seismic hazard modeling.
Additionally there are other statistical distributions than either
characteristic/quasiperiodic and random (Poissonian) that produce different
behavior [2,3]--with some models, the longer it's been since the last
earthquake, the longer it will be until the next, and with others after some
time for stress to renew on the fault, it becomes basically random.

For storms, floods, etc. the likelihood of a big event happening in a given
year is more or less equal every year and therefore 'random' with the
exception of some multiyear cycles such as El Niño. However, over shorter
timescales, they aren't. Big storms are more likely to occur during rainy
seasons rather than dry seasons, and big floods are more likely soon after
previous big floods (i.e. days to weeks) because the meterological conditions
that generate them may be persistent and the groundwater is still high, which
means that it takes less rain to get the same river levels.

[1]: [http://rocksandwater.net/blog/2016/07/wrightwood-
recurrence/](http://rocksandwater.net/blog/2016/07/wrightwood-recurrence/)
[2]:
[https://pdfs.semanticscholar.org/3071/de51c5abc4f770b0b11ede...](https://pdfs.semanticscholar.org/3071/de51c5abc4f770b0b11ede9f3b4d204c16aa.pdf)
[3]:
[http://windofweef.jp/library/o_m/disaster_prevention/img/10....](http://windofweef.jp/library/o_m/disaster_prevention/img/10.1.1.133.9909.pdf)

~~~
njarboe
How one can talk about earthquakes without mentioning plate tectonics [1] is
baffling to me. It is a completely coherent theory on how geology works and
the last real paradigm shift in the sciences. On the order of Newton with his
laws of motion for physics. Or the atomic theory of matter for understanding
chemistry.

In brief and simplifying:

Relative to each other, the Pacific plate is moving to the northeast and the
North American plate to the southwest (absolute motion is a bit different) and
a fairly constant rate of about 25cm per year. Being solid rock these plates
don't slide past each other continuously (except in a few rare places) but
build up stress over time near the contact between the two plates (fault).
When the stress is high enough, the fault breaks loose at a single location
and propagates a distance from there. How far the break propagates and how
much the plates move relative to each other determines the size of the
earthquake.

How plates move on the large scale relative to each other changes on the
million year timescale, so on the 10,000 yr timescale, where you will have
about 50-100 ~7.5 to 8.0 magnitude earthquakes on the San Andreas under San
Francisco, the mean frequency and standard deviation of earthquakes won't
change much. Geologist can determine when large past earthquakes occurred by
digging trenches through faults and looking at the physical displacement of
sediments [2].

How to predict earthquakes by better than 30% chance in the next 30 years
(this is the current best estimate for the Hayward fault near where I live) is
on-going and with no success so far. Looking at changes in ground conductivity
some weeks and days before an earthquake is the most promising path at the
moment, but has not yet been proven to work.

[1]
[https://en.wikipedia.org/wiki/Plate_tectonics](https://en.wikipedia.org/wiki/Plate_tectonics)
[2] [https://earthquake.usgs.gov/learn/topics/safz-
paleo/](https://earthquake.usgs.gov/learn/topics/safz-paleo/)

