Hello everyone and welcome to today's
Critical Issues Webinar, "Communicating
Cascadia's Earthquake Risk". My name is Leila Gonzales and I'll be the moderator today.
We'd like to go ahead and thank our
co-sponsors for today's webinar:
Western States Seismic Policy Council,
the Oregon Seismic Safety Policy
Advisory Commission, and the US
Geological Survey. In today's webinar
we'll be hearing from Chris Goldfinger
from Oregon State University who'll be
talking about the science behind the
Cascadia subduction zone risk and then
we'll be moving on to hear from Jeff
Rubin about earthquake preparedness and
response: science to action, and then
we'll be hearing from Tom Brocher who'll
be talking to us about how to
communicate Cascadia subduction zone
earthquake hazard, and then after the
presentations are over, we'll be
having our Q&A session with the
panelists where we'll be fielding your
questions and at that point.  And now
we'll turn the slides over to Chris. Well
thanks Leila. Good morning or afternoon
everyone. This is gonna be a little
difficult to squeeze this into the time
but I'm gonna give you a brief thumbnail
on the seismic hazards in Cascadia, and
this is just a smattering of co-authors
but there have been many many others
over the years. And so just a quick
look at what a subduction zone is, just
using Cascadia to help illustrate that -
A subduction zone is a plate boundary where
you've got a typically an oceanic plate
that is stronger denser and heavier
sliding underneath and oceanic I mean a
continental plate, and in this case
you're looking at a cross-section of
central Cascadia with Oregon on the
right and the Green Mountains and so on
and that lumpy blue area up on top is
called the accretionary prism where
sediments are scraped off of the
down-going Juan de Fuca plate and in the
for a variety of reasons the plate
boundary is locked and the source of the
earthquakes is offshore at Cascadia. 
So that red bar at the top or that
gradational bar on the top shows
approximately where the earthquakes are
expected to come from based on
thermal geodetic and GPS studies. So
Cascadia was originally a bit of an
enigma - a subduction zone that failed to
generate any earthquakes after plate
tectonics was discovered in roughly the
early 60s. And so Cascadia has been an enigma since that time and still
generates very few earthquakes, fewer
than any other subduction zone on a
day to day basis. And so there's a lot of
speculation about why that was over the
years but in about 1985, well in
exactly 1985, John Adams, a Canadian
geologist, was the first to write a
little abstract for AGU suggesting
that some offshore evidence might be
directly interpreted as evidence of past
great earthquakes, and that kicked off a
paradigm change that proceeded through
the late 80s and early 90s. So USGS
geologist Brian Atwater discovered the
stratigraphy that you see on the right which
amounts to a peat deposit, I don't know
if you can see my mouse, but a peat
deposit overlain by a sand sheet and a
mud deposit and then a modern marsh on
top of that. And this is quite a
difficult stratigraphy to explain
apparently there were marshes that were
at two different elevations in time. Either that or the land level had
actually changed relative to the ocean.
And so Atwater proposed rather boldly
and successfully that the land level had
changed relative to the ocean
and not only that but had done so very
rapidly and interpreted the sand sheet
where the shovel is poked in right here
on the left as a tsunami sand sheet
and so that rather neatly explained the
stratigraphy as an elastic land level
change accompanied by a tsunami. And so
right then and there in 1987 the
paradigm change occurred essentially
transforming Cascadia from an aseismic
subduction zone to one that could
generate the largest type of subduction
zone earthquakes. And then in the early
90s
colleague Kenji Satake in Japan looked
at records of a tsunami that arrived in
the year 1700 that seemed to be
unaccompanied by an earthquake. And the
timing matched Brian Atwater's work in
in Cascadia quite well and so through a
rather amazing sequence of sleuthing
events that earthquake was pinned
down to January 26 1700 at about 9 o'clock at night. And at that time only Native Americans
were there to witness the event. And so
here's Brian and his preferred habitat
digging in those deposits in Willapa Bay
and accompanying them were what became
known as the ghost forests and those
trees on the left shot are dead western
red cedar trees that were killed but
still standing today but they were
killed by the 1700 earthquake by
saltwater intrusion as they were lowered
into the bay during the earthquake. And
surprisingly these trees are still
standing today. And so here's how
that works. The elastic sequence is shown
on the left where elastic uplift in the
pre-seismic period is shown here and the
leading edge of the plate is dragged
down at the tip on the west and then
during the earthquake you have
to recover that that elastic energy and
the coast subsides and a leading edge of
the plate bounces forward and up
generating a tilt to the seafloor and
that generates the tsunami. And then in
in detail here's the sequence that Brian
laid out onshore where you have a tree
growing close to the edge of the bay. 
During the earthquake it drops roughly a
meter and puts the trees into the bay. 15
minutes to 30 minutes later the
tsunami comes in, lays down the sand
sheet, and then you have a sand sheet and
and dying trees but still in the bay. And
then through the next seismic cycle
uplift occurs and brings that whole
system up back up above sea level again.
And so at the same time John Adams
kicked off work offshore and I took
up with that in the mid 90s as well. And
so during the earthquake a lot of
phenomena occur including subsidence of
the coast and uplift of the offshore, but
the ground shaking generates submarine
landslides offshore and onshore in lakes as
well, and that phenomena was proposed
originally by Adams as a potential way
to get at long-term earthquake records. 
And so pursuing those records after
Adams early work in 1985 and then in 1990,
we've used these core samples offshore
this is just a small subset of them in
grey, and Adams original hypothesis was
what I would call a coincidence test. He
proposed that because there were 13 post
Mount Mazama eruptive turbidites in all of
the cores that he saw, he suggested that
was a huge coincidence and that
earthquakes were the most likely
phenomena responsible for that because
other generators of landslides would be
expected to be random. And it's an
interesting story that I won't have time
to go into in great detail, but if we
fast forward now to present-day
we look at these core deposits in a
geophysical view and that's what we're
seeing here in this slide, and these are
these blue and light blue and dark blue
wiggles are the density of magnetic
properties of core samples offshore and
what we do today is we use oil industry
well logging correlation techniques to
try to test these deposits to see if
they can be linked from site to site to
site along the length of the subduction
zone, and we do that in addition to
radiocarbon dating each of the deposits.
Radiocarbon dating gives permissive
agreement for most of the events, but the
error ranges for radiocarbon are quite
large so you can't really use
radiocarbon to to pin down the identity
of an event and define or determine
synchronaeity.
The well logging techniques on the
other hand provide an alternative way to
to test that and see if deposits are
really very very similar from place to
place, and we think that they do just that, and so the
stratigraphy now has been laid out in
terms of both time and structure and
what we wind up with is what we
believe to be a very coherent story of
earthquakes along the Cascadia margin. 
And so here's a slide showing as if you
could drain the water out of the ocean
and showing the paths of these
submarine landslide generated turbidity
currents out through the Cascadia margin.
And so a typical core sample looks like
the small picture at the upper left. It
has just a very simple series of
turbidite deposits that alone, as
John Adams showed, could be used to
provide a preliminary test for a earthquake
origin, but with radiocarbon and
the other tools have provided a much
more solid basis for the earthquake
hypothesis. And so here's just a close-up
of that slide and the equipment used on
a large vessel to collect it on the
right. And so it turns out that in
addition to the offshore we have been
finding these deposits in lakes as well,
and this is barge coring rig on Bull Run
Lake in the western slopes of Mount Hood. And normally though the offshore cores are collected
on a big ship like this and it's quite a
quite a large industrial operation so
it's been kind of a quite a boon to be
able to find out that some of this work
can be done closer to home in the lakes. 
And so here's just a sample correlation
diagram where we're attempting to correlate
Bull Run Lake to to offshore cores and so
far we think that's a promising
methodology. So now I'm going to leap
over about 15 years of work and get into
the results. This is an updated panel of
segmented Cascadia earthquakes that we 
currently think have occurred in the
past 10,000 years. And so this this
integration includes all the onshore
data including Brian Atwater's, Harvey
Kelsey's, Alan Nelson, Rob Witter, a host
of investigators have worked in every
bay essentially along the Cascadia coast
and that's integrated now with the
offshore turbidite data and with
considerable wiggle room for error,
this is the updated model of what
what I think has occurred in the past. So
on the left you see full margin ruptures
that are have some doubt at the south
end and some uncertainty at the north
end as well, but there are roughly 19 of
these events that seem to extend along
much of the length of the Cascadia
margin including the now-famous 1700
earthquake. Panel B shows several events
that extend up to about the middle of
the Washington margin. Panel C, about
eight events that extend up to about the
Columbia River. Panel C prime - some of 
the few events that extend up to
about Central Oregon. Panel D, about 10
events that extend up to about Cape
Blanco, Oregon, and Panel E, some
much smaller events down in northern, limited to
Northern California. We have a single
event in Panel F that seems to have
occurred only off of Washington. So you
can see right away that these the
rupture modes of these events vary quite
a bit. There are, there have been a number
of lengths of events and length implies
magnitude in the case of subduction zone
earthquake, so the ones on in Panel A in
the upper left are much larger
earthquakes than than B or C or any of the other panels. So here's a sort of human scale timeline with
ten thousand years or I guess eight
thousand years, no - ten thousand years
before present on the left. You are here
at present day on the right and some
just interesting points in history. This
was made by Ian Madin at the Oregon
Department of Geology and Mineral Industries
and just updated just last week with
some slightly new events. So this is one
that we used to put this on a
human timescale 
for the public quite often. And so with
the long paleo-earthquake
record that we have 10,000 years long we
can start to look at things like the
distribution of these events in time. So
this is two versions of a possible
clustering model. You can see that
they're not evenly distributed in time.
For example there are five events here
and these have a recurrence time on average
of around 300 to 350 years, and then
there's a thousand year gap here where
there were no large earthquakes. Then we
have another cluster of about five
events and another thousand years gap
during which there were no very large
earthquakes, and then it gets a little
less clear whether this is clustered or
not. So an important question today is
whether this is just random, which is
entirely possible, or whether it's
actually a dynamic system 
that's driven by something and driving
this clustering. And of course what comes
next is an equally important question.
And so this plot is another way
to look at what might lie in the future.
This is a log:log plot showing the
recurrence times between pairs of
earthquakes in blue with their error
ranges.
Present or 50 years from now is shown by
this red line and the red target, bull's
eye target. And so if we want to look at
probabilities in the next 50 years this
is one way to do that. And so this is for
the northern margin, which has a repeat
time earthquakes of about 500 years. And
you can see from this that in the
future that is to the right of the 360
year line, most of the recurrence times
lie in the future. So we haven't exceeded
the mean repeat time and we haven't
exceeded that many of the repeat times
for the northern margin. The ones that we
have are over here on the left of the
target. So the conditional probability
for the northern margin, which includes
Vancouver and Seattle, is about
7 to 15% in the next 50 years. 
On the other, hand if we look
at the southern margin, it's a different
story. You have a much higher frequency
of smaller events in southern Cascadia
and the image is just
flipped. So in the future 50 years there are only
six or seven events here that have
repeat times longer than 360 years and
they're here on the right of the target. 
All of the other repeat times are on the
left of the target. And so that means
we've already exceeded all of these
repeat times. We only have a few left. And
so what that translates to is a
conditional probability in the next 50
years of 32 to 42 percent for
some points in southern
Cascadia. And most recently I'll just
wrap up with some work we've been doing
in the lakes. All of our, all of the
risk to people in Cascadia is mostly
inland while so far most of our evidence
is either offshore or right along the
coast. So we've been working at lakes to
try to get at ground motions at inland
sites. And so here are some divers in
Bull Run Lake, Oregon using shear vane
testers to look at slope stability in
the lake. And these lakes contain
turbidites much like the offshore and so
we're looking at trying to estimate
ground motions for these inland sites
that are closer to where the
people live and therefore more relevant
in that sense. And so in this last slide
these are slope stability calculations
for Bull Run Lake for some work just
recently completed and the caveat here,
this is not published yet, but so this is
work in progress, but so far what we're
seeing is that ground motions that we're
estimating and ground motions estimated
recently for the USGS national seismic
hazard maps are actually quite
compatible. So for an extreme
event at this site we had a maximum peak
ground acceleration PGA of 0.3 G which
is essentially the same results shown in
that in the 2014 national hazard map. So we're encouraged at this result and we think this
maybe provide a way forward to providing
some ground truth to the national
seismic hazard maps for inland sites. And
I think my time is probably up so thanks
very much. Thanks very much Chris. I'm
going to go ahead and change the slides
over to Jeff. 
Great. Okay, thanks a lot. So I'll echo the
good morning / good afternoon and follow on
from what Chris was talking about in
terms of now that we have the geological
information or a better sense of the
hazard what we've been trying to do
about it on both the policy level and
implementing policy level. So this is
what we're going to be covering and some
of it is just a pitch for the role of
geoscience plays in in policy
development and then how we apply that. And we have a pretty large audience
today and for those of you who are familiar
with what's been going on in Oregon some
of this will be a little bit of review
but a few years ago we had a resolution
passed in the Oregon House led by
representative Deb Boone and it directed
our the Oregon State Seismic Policy
Advisory Commission, OSSPAC, so despite
its acronym it is a standing statutory
committee it's not a PAC, to create this
Oregon resilience plan for the reasons
shown in the red , you know protect lies
keep commerce flowing, and it specified
the scenario the megathrust earthquake
and tsunami. So the report was issued. It
was a one-year process. You can
see on the right almost a hundred seventy
volunteers, a budget of exactly zero, one
year to get it done. We had nine working
groups. We based it on a single scenario
and we had water, wastewater, power,
communications, transportation, etcetera, and
those were the priorities there in that
upper right box. So this was the
scenario - the magnitude nine
Cascadia subduction zone. We divided the
state into four broad zones: the tsunami
inundation and then the coastal area minus
the tsunami, inland valleys and finally
eastern Oregon, and you know the different
types of damage once you get away from
the tsunami inundation obviously at the
coast much stronger shaking in the inland valley as Chris just alluded to we mean
that we're not looking necessarily at
the intensity of shaking that they'll see
at the coast but certainly still
prolonged shaking and extensive
liquefaction which would be really
really devastating for this area given
the buried infrastructure. Threw in a
couple pictures from other
earthquakes because you know while it's
been at the cost of other people in
other areas we've been able to learn a
great deal from the large number of
substantial earthquakes over the last
ten to fifteen years. This is a picture from
the Christchurch area from their
substantial, it was not a subduction zone
earthquake, but this used to be a
residential subdivision that is now
uninhabitable. You know it didn't used to
you used to have to go farther to go to the
beach than walking at your front door. So
this type of liquefaction isn't just a
temporary inconvenience. You know there
were I think close to a thousand homes
that were deemed unlivable. That means we can't build here again and most areas
this size even larger don't have that
many available housing units to put
people in. That's a significant problem. 
Certainly in our area of Portland metro
area you know we have a very very high
occupancy rate and that is true for a
lot of the west coast. That's going to be a
problem if we have to condemn
certain areas. More examples of some
pictures from Yumei Wang from
DOGAMI, and currently the Office of the State Architect is looking at the impact of weak
soil. This is a really big issue for us
because as I said we may not get really
intense shaking, we'll probably get long
duration shaking but a lot of
liquefaction especially in the northern
Willamette Valley which is where a
good portion Oregon's population is. 
It's really likely to be devastating. The
bridges between the inland valleys and
the coast, for those who do survive the
tsunami, even if they don't collapse, I
know I wouldn't want to be the first
person to drive over them, and that's an
ongoing weakness and it's not something
we're going to be able to change
overnight. One of the reasons the Oregon
resilience plan looked at a 50-year
perspective is because we don't have
tons of money, and we can't just
suddenly change all of our
infrastructure. So it's going forward how
do we prioritize things? What do we want
to do when we build new? When we replace, what are some of our options
for both built and un-built? 
But it actually gets worse than that.
It's not just the issue of the
liquefaction and the strong shaking. It's
the secondary effects, and what that
actually means to us. So you know for us
a lot of it comes down to lifelines and
that's one of the main issues with any
earthquake. We have a lot of
vulnerabilities. We have a lot of
interdependent lifelines connected to
each other - water, wastewater, electricity...
We know that in our area certainly the
service area for my agency, the most
densely populated part of the state,
transportation system just between the
damage to the bridges or the approaches
to the bridges, the impact on the
roadways themselves, the loss of power
for traffic control, it's going to make
it extraordinarily difficult to not only
respond to emergencies but simply to
move supplies around because if you
can't distribute things by
ground one way or another, simply relying
on even large helicopters is just
it's not practical as a sole source of
distribution. And along with that, we have
really extensive vulnerabilities as far as
fuel that I'll show in a couple of
slides from now, but the having enough
fuel to operate vehicles and emergency
generators we know we're going to run
short of that, and while we're planning
for that, there's only a certain amount
that we can effect in advance. And then
the last piece is the challenge of
in this part of the world we don't get a
lot of major disasters. The Pacific
Northwest Coast they get a lot of big
storms and they're far more accustomed
to really disruptive events, but outside
of that you know our last two
presidentially declared disasters for
the Portland metro area were snow and
ice storms, and you know what amounts to
a major inconvenience. So we're trying to
generate awareness or a culture that A)
isn't really used to disasters at all, B)
has no collective memory of large
earthquakes, and C) really only determined
they were a seismic hazard zone really
just a few decades ago. So we don't have
a lot of cultural knowledge, our codes
are still catching up. We have a lot of
old buildings and unfortunately within
emergency management, emergency
preparedness a lot of so-called best
practices really amounts to something that was
derived from an area where events are
more common and where they come with
warning - i.e. hurricane alley - and a lot
of those concepts which are you know
might not even reach the stage of expert
opinion don't apply well here. So it's
not that we're making it up as we go
along, but we have a lot of challenges in
both creating functional protocols and
alerting the public. We do a lot of
exercises. My agency this year
we'll be doing again, and actually the states
of Oregon and Washington, FEMA Region 10, will be doing a multi-day earthquake
exercise for that same Cascadia scenario.
We do no landline phones, no cell phones,
no 800 megahertz radio system for
a full day, but we still can't simulate
the difficulty in getting around the
challenge in getting people into work,
the fear that people have for their loved
ones, and just the really large scale
disruption. So a lot of different
challenges in the "what do we do about
this" side. Next couple slides are from
the Oregon resilience plan itself and it
just shows where some our
vulnerabilities are. You can see the
on the horizontal axis the decade that our
public schools, K through 12, are built in green,
the public safety buildings and then
community colleges, and you look at where
the median is, you can see where most of
them are, and most of those were before
we had any seismic codes at all, and it's
really only a tiny portion that were
built under modern seismic codes. So we
have a lot of vulnerable buildings. This
is from Nate Wood from the USGS and it's
directly applicable to the resilience
plan. It shows the degree of population
risk that we have in the tsunami
inundation zone along the coast. What it
doesn't show, which is also in the Oregon
resilience plan, is about 80 to 85
percent of the critical infrastructure
along the coast is in the inundation
zone as well. So we're looking for a
really a catastrophic impact and a
really long term impact as well. The nice
thing is that Oregon statutes allow us,
really encourage us to use science, the
Oregon revised statute that was passed
in the 90s that generated our initial
restrictions for development in the
tsunami inundation zone recognized that
scientific evidence
may improve in the years and so there's
a way to, since DOGAMI has updated their
their maps, we don't need an act of the
legislature to put, to adopt those
formally and make those the new lines of
demarcation, and in fact that that will
be starting during the
current year. Here's the you know the
best way to summarize the ORP is this is
a direct quote: "We will have very large
earthquakes. We are poorly prepared, and
we need to do something about it." And
that hasn't changed in the two-plus
years since the plan came out, but we are
starting to do something about it. We
know that we're going to have large
casualties. Most of the modeling programs
like HAZUS, if you have enough
site-specific information are pretty
good for projecting various types of
damage, pretty bad for projecting
casualty rates, but you know this order
of magnitude one to 10,000 is certainly
reasonable. Quite a lot of them
in the subduction zone, huge economic
loss - tens of billions of dollars and of
course that would affect the rest of the
country not just the state of Oregon,
huge amount of debris - the pictures in
the bottom of the slide show our one
large centralized fuel hub in Portland
near Swan Island in the Lima River and
that's fill and is easily liquefiable
soil. We don't have a lot of reinforced
facilities there, so aside from the fact we
probably will lose a lot of those tanks, we'll
also lose the fuel that's going to be
filling the pipelines that supply a lot
of our our area, they supply the airports,
they supply liquid fuel lines that run
through there. The pipelines themselves
would likely would be damaged. So aside
from not wanting to swim downstream of
this for a while, it really highlights
our liquid fuel vulnerability
affecting our ability to respond and
recover. And this is a USGS shot just
view it as a schematic, don't worry about
what what color is what, but all those
different lines - water, wastewater,
electric, transmission, natural gas
pipeline, liquid fuel pipeline, highways,
airports - those are all the life lines in
this area much of which is at high risk
from either liquefaction or at least
amplified shaking due to soft sediments,
and that's a lot of
infrastructure to address. A lot of
infrastructure to even inspect.
So one of the things that we did about
this was in the 2013 legislature the
same year that the Oregon resilience
plan was presented, another bill
was passed to create what we call the
Oregon resilience task force
with the mission that's indicated right there you know basically we have this big
Oregon resilience plan, how do we start
implementing it? You can see that the
link to that report is online.We
had to define resilience and the
Oregon resilience plan did a pretty nice
job in doing this. Sometimes I always thought it
was easier to show what resilience is not
because resilience is a really popular
buzzword now and you can probably
find 60 or 70 definitions. The shot on
the left is the Fukushima complex before
the tsunami and on the right is after
the tsunami. That's a really good example
of something that isn't resilient but
for us we look at this conceptual
diagram that Yumei Wang created and you
can see we start out you know
everything's good and when the disaster
hits the goal is to A) minimize the
amount of time it takes us to recover
and B) when we do recover, we want to be
in a better situation than when we
started, i.e. we don't just want to rebuild
everything in time for the next disaster
or rebuild everything to the same
standards. So you can see where we
want to move that line upward and the
response time to the left so we're not
in as big a hole and we're not taking as
long to recover and we do have a long
ways to go. That's why we're doing all this. So
what I'm going to finish with is what we
did. We issued our resilience task force
report, a whopping two pages plus a cover
letter in October of 2014 in time for
the long legislative session that
started this past February, and we had a
whole series of lists we wanted
oversight, we were recommending
investment in more seismic rehab funding,
transportation backbone, a better
assessment inventory of what we had for
multimodal transportation, education, land
use, and we got some of what we asked for and we got some that we didn't ask for, which is
still useful
there's still stuff left to do. Our one
item that we singled out above all else
was creating a position of State
Resilience Officer which was passed in
House Bill 2270, and it's not that we
wanted to create another government
position. I actually wasn't originally a
big supporter of this when it came out
in the Oregon resilience plan, but you know
after serving on two of these committees
as have several other people, we
realized we needed something besides yet
another series of unfunded ad-hoc all
volunteer committees, and there had to be
someone appointed by the governor
reporting to the governor with some
authority and the ability to keep all
the different pieces, land-use, funding,
codes, education, you name it, on the radar
for the governor's office and coordinate
all the different entities available. So
that was passed. It was signed into
law, and now we're working on trying to
determine what that position is going to
look like and how we're going to fill it.
Some measures to assist seismic rehab
for multi occupant buildings - a really
large piece a bit unexpected,
the legislature funded put additional
authorization for general obligation
bonds to be sold that have been approved
by the voters already back more than ten
years ago more than two hundred million
dollars for schools and public safety
facilities. We made a kind of foot in the
door for addressing some of the health
care needs and ability to fill
prescriptions, and this is what's next
and DOGAMI
Ian Madin, the acting state geologist, has
committed to moving forward with the
DOGAMI Board of Governors to adopt the
updated inundation maps that will move
the lines that restrict certain types of 
development a little bit more landward.
We know that we need to promote really
vigorously this the coordination at the
state and local level to provide more
land use options for communities that
are largely in the inundation zone and
they don't have a lot of other options
for development. We had some bills that
did not make it through but we're
looking at other options for the short
session, for the next long session and non
legislatively. We know that the human
side mass care and shelter access to
medical care that's going to be huge and
whatever solutions we could come up with
this would apply to any other disaster. 
It's a really big piece of this. It's the
part of resilience that is really
difficult to get your hands on because
it doesn't relate to codes. It's a lot
more difficult to quantify, but it's
still very important. We've already talked about the fuel vulnerabilities a reminder
that our resilience task force report
was only intended to address the
specified first biennium of 2015 to 17
and to get stuff going but obviously
this is going to be an ongoing process.
And you know as an emergency manager I
always like to point to contingency
plans. So if you find yourself on the
coast in the lovely community of Wheeler,
you will find this facility and
with that I'll thank everyone for tuning
in. I look forward to the Q&A piece after the presentations are done. Great
Thanks so much Jeff. I'm going to go
ahead and turn the slides over to Tom. So
I'm Tom Brocher. I'm with the US
Geological Survey in Menlo Park
California, and I welcome this
opportunity and I'm very thankful for
AGI to talk about how we might
communicate Cascadia subduction zone
earthquake hazards, and again we're
talking about an earthquake that shown
as occurring on this big pink patch on
the map on the right or subsections of
that fault patch. So we've learned a lot
of lessons from previous earthquakes
about how we communicate hazards and one
of these is to provide the context of
the hazard and the earthquake
perhaps. In the Bay area we often talk
about the hazards in terms of what was
experienced in the 1989 Loma Prieta
earthquake and in my presentation this
morning I'll be talking about the
Nisqually earthquake as a touchstone
for people to get a sense of what the
Cascadia subduction zone earthquake
might be like. We need to be realistic
when we talk about the hazard. There's no need
to to make them larger than they are. We
need to be clear about what we know and
what we don't know and make sure that
everyone appreciates the fact that our
knowledge is going to grow over time. We
need to communicate our community our
messaging with emergency managers
engineers and public health officials so
that we're all speaking with the same
voice. If we have mixed messages that
will lead to confusion and confusion
leads to inaction, and we need to make
sure that we use very simple language
and we present the material in a variety
of ways. If we want to encourage
preparedness,
one good approach is to show how
preparedness has made a difference in
the past, and a couple of examples that I
like to use are shown on these
illustrations on this figure. One shows a
retrofit house and it turns out there were
two adjacent houses built the same way at
the same time with the same materials that
the same property owner bought in Santa
Cruz, and he retrofit one house before
the 1989 Loma Prieta earthquake but he
hadn't retrofit the other. The
retrofit house did very well and
sustained only limited damage. The
un-retrofit house house was split apart in
four sections and required extensive
rebuilding and in fact it had to be
jacked up and placed on a new foundation.
So a little bit of retrofitting can go a
long way and we know that that works. The
other is drop cover and hold and we
like to encourage that and we've just
had the annual shakeout exercise
yesterday. Most injuries that
result in earthquakes occur because
people are pushed down by the earthquake
or fall over or things fall on top of
them, so by getting out to the ground as
soon as possible and covering yourself
you can hopefully avoid most of the
things that injure people. Also what
works is to I found is that people like
to know what's been done - what actions
have been taken by governments and other
agencies to prepare for the earthquake.
Once we tell people about the hazards,
people want to know what they can do to
prepare, so it's important to tell them
that. And showing, since we were social
animals, showing pictures of people
preparing can be very effective in
leading others to take action. So it's
been mentioned by Jeff and Chris
there have been about six large a
subduction zone earthquakes in the past
50 years that we can learn from. Three
have occurred in Chile, one in Alaska, one
in Sumatra and one in Japan. And all
these have given us new lessons on how
to survive earthquakes and tsunamis, how
to prepare for these hazards, and have
improved our building practices. And
after each of one of these earthquakes
the US sends teams of geoscientists
and engineers to learn these lessons, and
recently there's been some good news. The
the modern building codes that are in
place in Japan and Chile have really
been effective in reducing the building
damage in modern buildings. So that's
really good news.
The biggest lesson probably from all
these earthquakes and tsunamis is that
almost all the property damage and
almost all the fatalities
result from the tsunamis that are
produced by these earthquakes and the
submarine landslides. Now in terms of
tsunami hazard mitigation, people need to
know that things are being done and so
the hazard is being evaluated by tsunami
inundation maps. Once those are developed
then evacuation routes can be
established, tsunami sirens can be put in
place. Training of the populations and
coastal communities is really important
so that they know when the earthquake
occurs that's their tsunami alert and
that they need to evacuate as soon as
it's safe to do so. Usually that's when
the shaking stops. Vertical evacuation
structures are being looked at as a
solution for people who have long
distances to travel before they can make
it out of safely outside of inundation
zones, and one is currently
being constructed in West Port
Washington as part of a newly built
elementary school. And you can see a
picture of that in the lower lower right. 
And as Jeff was mentioning avoidance of
the hazard altogether by land use
planning and zoning might be another
tool in our toolchest to mitigate
tsunamis, but I want to return to the
earthquake shaking hazard for a while
and I want to make sure everyone's aware
of that the Cascadia subduction zone
earthquake has been included in the USGS
national seismic hazard map since 1996
and in the building codes since about
2000, and that both the national seismic
hazard map and the building codes are
updated about every six years to
incorporate the latest science into
local resilience. Now as I said before
and I want to emphasize in both the
recent Japanese and Chilean earthquake
subduction zone earthquakes some of their
building codes have been very effective
and preventing significant building
damage. Other tools for hastening and
planning for these events are scenario
maps, and I'll show some examples of
these, and the USGS is also performing
supercomputer simulations of what a
subduction zone earthquake might look
like and the strong ground motions that
it will generate, and these include
realistic geological models of the crust
along the I-5 corridor and elsewhere
along the coast. And these all show that
the ground motions in the I-5 corridor
will be lower than that they are along
the coast and I'm showing you here a
scenario shake map for a magnitude 9 a
wall-to-wall rupture of the entire
subduction zone for Cascadia, and so the
bright colors in this scenario map
correspond to the highest levels of
shaking which are intensities 7 or 8 or
so. 
Now the little inset to the left shows
you an actual shaking map that was made
from observations from the 2000
Nisqually earthquake which was a magnitude
6.8. And one of the points I'd like
to make is that the shaking levels from
this Nisqually earthquake in the Puget
lowland are comparable to what we expect
from the Cascadia subduction zone
earthquake in Seattle but all along not
only Seattle but all along the urban I-5
corridor. So the shaking levels per
se are not expected to be any higher
than the Nisqually earthquake type
levels. Now it's true that the duration
of shaking is going to be longer and
that a much larger area is going to be
impacted but the levels of shaking are
something that we've seen before
and the and this may not and this is
kind of a surprising result from these
scenarios but the good news for us is
that the shaking levels are reduced by
the fact that the earthquake is
primarily offshore and is located at
some depth. So that helps us reduce the
shaking levels that we can expect. If we
look at a smaller earthquake similar to
some of the smaller patches that Chris
showed in his presentation, they have
paths that might produce a magnitude
8.3 earthquake. We see that this is still
true that those shaking levels along the
I-5 urban corridor are about the same as
we have seen in the
Nisqually earthquake. Now Chris alluded
to the fact that there are a lot of
uncertainties and unknowns about what
the next subduction zone earthquake is
going to be. How big it's going to be.
Where it's going to start and how far
down towards the coast it's going to
rupture, and the advantage of the USGS
national seismic hazard maps is that
they incorporate all these unknowns and
uncertainties as different possibilities,
and they also including the possibility
that one of these magnitude 8.3
earthquakes along the subduction zone
could occur anywhere on on the subduction
zone. We also have tools in place and
we're developing them more to mitigate
aftershocks and we haven't talked about
aftershocks very much yet but we've
experienced in these prior large
subduction zone earthquakes that they
are going to be very large and numerous
magnitude 6.7 aftershocks that will
begin immediately after the earthquake.
They're going to be widespread and
they're going to occur along the main
plane that produced the earthquake.
They occur within the oceanic
crust, and some of these will occur in
the crust of the coastal ranges. For that
reason they can cause additional damage.
They can hamper rescue operations and
they can also take a psychological toll
on people because they will be ongoing
for months following the main shock. 
The USGS routinely issues aftershock
forecasts after large earthquakes
talking about the numbers and magnitudes
of earthquakes to expect, and after the
1989 Loma Prieta earthquake the USGS set
up a system to issue real-time
aftershock alerts to rescuers working on
a collapsed freeway. And that's based on
earthquake early warning where when we
have an earthquake it produces two
different types of earthquake waves. The
first wave is not very damaging and it's
followed by the more damaging waves shown
in red here. We can using sensors that
are on the ground which I think of we
can think of as tripwires,
the sensors can detect the earthquake,
determine its location or its epicenter
and then estimate its magnitude and it
can relay this information forward of
the earthquake before the damaging
earthquake waves arrive. Now we're
currently partnered with the University
of Washington, University California
Berkeley and Caltech to develop
we developed a prototype earthquake
early warning system called ShakeAlert.
A similar system was in place in Japan
for their magnitude 9 2011 Tohoku
earthquake, and it worked for
that event. ShakeAlert will provide up to
a few minutes of warning for a Cascadia
zone earthquake. The farther one is from
the epicenter, the more warning one 
will get, and it has many uses but among
the those uses is that it can be used to
provide aftershock alerts which can help
reduce some anxiety and it can certainly
be used to inform rescue operations that
are in partially collapsed buildings. As
Chris alluded to there will be a new
coastline along the Pacific Ocean after
this earthquake and that's because
there's going to be an instant and
permanent lowering of the coastline of 3
to 6 feet allowing daily tides to reach
in much further into low-lying areas. So
one can think of this as an instant sea
level rise as well of 3 to 6 feet and so
this will have an instant flooding
hazard that will result as well as a
longer-term coastal erosion effect, and
this slide, the background of this slide
shows Brian Atwater our USGS geologist
and some of the dead trees that died
because the coastline went down 3 to 6
feet and killed the trees back
in 1700. As both Chris and Jeff
alluded to we know we have
vulnerabilities along the subduction
zone. We have a lot of built although we
have very good building codes in place
now there are a lot of buildings that
were built before these codes and so
these are some of these are vulnerable.
The most vulnerable of these are
unreinforced masonry buildings , buildings
that have structurally weak first stories,
buildings that are older and
built-in soft soils and soft deposits
and some of our taller buildings in
sedimentary basins which will shake at
the frequencies that the sedimentary
basins will shake. Just so you know
both the cities of San Francisco and Los
Angeles have passed ordinances requiring
mandating the retrofit of some of these
most vulnerable buildings so that those
cities are more resilient to the earthquakes
that they are expecting. We also have
significant tsunami evacuation
challenges as Jeff alluded to. This
figure on the bottom shows a figure from
a recent USGS authored report that shows
the communities numbered up to 73 from
Washington, Oregon and California showing
the numbers of residents as a column and
the color of the column or parts of the
column reflect whether it's possible for
those residents to evacuate to higher
ground at a slow walk, a fast walk, or if
it's not possible, and so there are
different communities along the coast.
Most of the communities are very small
and they can be evacuated at a slow
walk, but there are a few that have
higher numbers of residents up to 12,000
or so and some of these residents cannot
walk their way to safety. So we have
different groups and different needs for
tsunami evacuation planning and
preparedness. I'd like to review very
briefly and this is one of my last
slides I think, an example of hazard
assessment that led to a very successful
mitigation, and this is an example of the
Alaska oil pipeline which was
constructed in the early 1970s,
and as the planning for the pipeline was
in place they realized the pipeline
would cross that Denali fault which is a
major strike-slip earthquake fault
very much like the San
Andreas fault and so geologists went out
to investigate the fault and they
determined that the fault produced
large earthquakes about every hundred
years and that the ground shifted during
these earthquakes about 15 to 20 feet. So
the engineering solution to that that
hazard was to place the pipeline on the
surface on Teflon skids with the theory
that when the earthquake happened the
ground was shift underneath the pipeline
and the pipeline would stay in place and
that's exactly what happened in the 2002
Denali earthquake which was a magnitude
7.9, one of the largest
earthquakes in US history. The pipeline
performed very well. It didn't spill a
drop of oil and the pipeline operations
continued very rapidly so that's a major
success story and it shows that these
hazards can be mitigated if we know
about them in advance and that's really
my the last thought I'd like to leave
you with is that you know we're very
fortunate in the Cascadia that we've
recognized the hazard before the
earthquake has happened. We can think of
many examples in human history where
this was not the case:  Pompeii, Krakatoa,
the 1906 San Francisco earthquake where
the hazard was not recognized and it
couldn't be mitigated. So here we have
the hazard recognized so now we can
mitigate it and to kind of reiterate
what Chris said along much of the
Cascadia subduction zone at least the
interval between large back-to-back
wall-to-wall earthquakes is something
like every five hundred years. It's about
a one in ten chance in the next 50 years
of a magnitude 9. Now to get some context
to that estimate the odds of a repeat of
a magnitude 6.8 type Nisqually
earthquake are about eight to ten times
higher. So if we prepare for a Nisqually
type earthquake that preparedness will
help us for the coming Cascadia event
as well. So I think that's my last slide
and thank you for your attention. 
Thanks so much Tom . We're going to go ahead
and move into our question and answer
session. So our first question that we've
got is "With the potential for so much
damage from a large earthquake, how do
you communicate the earthquake science
in a way that doesn't result in inaction
because the problem seems unmanageable?" Well that's a great  question. One
of the things that the Tom mentioned
that's really important to know is that
the ground motions from these large deep
and far offshore subduction zone
earthquakes are not as immediately
catastrophic as most people would tend
to think and people who've ridden
through say the Loma Prieta or Sylmar
earthquakes tend to equate ground
motions with something like that and
then extrapolate that to a magnitude 9
which isn't the right isn't the right
analogy.
The ground motions are actually
relatively modest and that the main
thing about it is that the duration is
very long and that our built our built
environment is very weak and those are
the those are the things to keep in mind.
That it's it's it's very possible to
mitigate as Tom was as Tom was pointing
out, and that it's not, not an
unmanageable hazard at all.
Yeah I would, I would agree with that
with Chris's comments and and again you
know we have tools to assess the
hazard ahead of time and with those
tools we can superimpose the built
environment our infrastructure, our
houses, our schools and so on, and so we
can from that superposition of the of
the hazard and the built environment, we
can we can understand the risk and we
can prioritize our mitigation efforts by
addressing the highest risk
scenarios. And this is Jeff, and that was the philosophy behind the Oregon resilience plan. We can't do everything at once
We want to prioritize what's most
important to get
first. We need to get started for a
longer term process. And even on an
individual level I mean there are
multiple programs in this area and
others that try to break down just the
preparedness aspect into manageable
steps but it's always a challenge to
communicate this is a serious hazard
you need to pay attention to
without unintentionally giving the
message that it's so bad that you're kind
of screwed regardless of what you do.
I guess I'd just like to follow up if we
could just to say that you know the
lessons from the I think we should
point people towards looking at what
happened in the recent large subduction
zone earthquake elsewhere and there were
definitely damage and fatalities but as
I as I tried to emphasize those are
mainly associated with the tsunami and
fortunately along Cascadia the coastal
population is not huge. It's not the bulk
of the population so we should be able
to design mitigation strategies for
those people and as well as for the bulk
of the people that will experience the
earthquake along the I-5 corridor that
are quite really quite far from
where the earthquake happened.
Thanks for the answers to that. I know
you mentioned a lot of the issues. Can
you talk a little bit more about what's
being done to mitigate those? Are you talking about for the coast in particular?
In the coast in particular, yes. I know for
Oregon we're trying to do a couple of 
different things. You know we're trying
not to be prescriptive to the Senate in
the sense of saying okay you can't build
here so figure something else out. For a
lot of communities if it's not in the
relatively flat area that is the
inundation zone
They get into the coast range pretty quickly
or other unsuitable areas to develop, so
it is a series of very difficult
choices and probably one of the best
examples of that is the hospital in Gold
Beach that's essentially being rebuilt
in the same area that it was before. It'll
be a better building but it's still going
to be a dangerous zone. Giving communities a
chance since they have to set aside
urban growth reserves - making it easier
for them to do so in less dangerous
areas and also streamlining the process
so that after disaster
rather than trying to say well here's
where we have to rebuild - giving them
more options so that they can rebuild
the extent that they plan to more
intelligently rather than simply using the
same area. Those are some of the
initiatives that we started working on
last year as well as having some of the
state agencies that are involved in this
having them funded to assist the
communities in the in the land-use
planning that they're actually required
to do under state law. Well I would just
add to that that it's that as Jeff and
Tom pointed out I think we all pointed
out that the this knowledge is
relatively new and individual
communities are still struggling with
exactly how to address it. And there
isn't a there is no one consensus to
this. It's a difficult problem.
You know people who live and work and
and own businesses on the coast, they and we all don't want the
coast to be closed for business and
people want to live at the coast and
that's going to continue, but how
to do that in a realistic way and in a
sensible way that'll prevent loss of
life in the future is a struggle
and so the Gold Beach hospital that Jeff
mentioned is one one example of that and
so it's a learning process I would
say, that mistakes will be made and some
good positive steps will be made and
hopefully those will evolve into
good directions in the not-too-distant
future, and as Tom pointed out we have
lots of examples of people around the
world that have done this successfully.
The Japanese example and even the
Chilean example and we can learn
from that. We don't have to start from
from square one to look for examples of
how to have a successful and thriving
society in a place with a hazard as
high as this. I'd echo what Chris just
and I bring in another example of a
community that's struggling with
resiliency and that's the city of
San Francisco and
they conducted a policy study to look at
they basically asked a question what
infrastructure and critical facilities
are needed to make sure and when they
are they needed in order to
make sure that the city 
will remain viable following the next
big earthquake on the San Andreas Fault
or the Hayward Fault. And so they
identified things like how soon do the
hospitals need to be open and operational?
How soon do police stations, fire
departments and transportation systems
and hospitals, and went
down the list and they identified where
the city was in terms of existing
infrastructure and where it needed to be.
And I think that's a good model for
communities that are looking at. I think
that's a good question for communities
to ask themselves is following the
Cascadia subduction zone earthquake how
soon do we want to be viable as a
community, or how do we make sure that we
always remain viable and that we're not
we're not shuttered by this the
earthquake and the tsunami. And you know
the solutions will be different in
different places depending on the
geography and the needs of the community
but I think that's a useful approach to
take. Tom, just to follow up I
agree with Tom with what he just said
about San Francisco, and and one 
very simple concrete step people might
consider taking when community
entities are trying to you know
struggling with what to do, is to take
field trips to places where there have
been successes, Chile and Japan in
particular, and rather than reinvent
the wheel just learn directly from
what's known to work. Great. Thanks.
We have one question here about how
have the implications such as
casualties, hotels in inundation zones, 
etc, have been taken into account if the
earthquake were to happen in the summer
months when you have a lot of tourists
in town? 
Because it's so
difficult to model casualties period you
know actual numbers are difficult the
bigger challenges you know how do you
get people out of the tsunami
inundation zone when you have a lot more
people there to begin with.
Nate Wood from USGS and others have done
some really good modeling in terms of
here's how long it's gonna take people
to get to the safety. Here's how long
they'll have. Factor in then the fact
that if they have to go over say a bridge even
if it's a footbridge to get to safety
will that bridge still be standing and
that drives some less conventional
options like tsunami resilient and
earthquake resilience structures that
are actually within the inundation zone
and telling people to go towards the
water instead of away if
that's the only way out. Those are some
of the options that are being used. Some
communities have actually moved forward
on that, but we know that in the summer
months there'll be more people on the
coast. There may be fewer people in the
valleys as a result but it doesn't change the essential hazards or
the needs it just adds a few thousand
people to the totals. Great, and overall
here's another question coming in from
the audience, how worried should we be
about the big one in the northwest? 
This is Jeff. From my perspective I don't
think you should be worried. I mean I don't
worry about it. I've never found that to be
really constructive. I think all of us
want people to pay attention and take it
seriously, but rather than fretting, do
something about it. Realize that if you
can prepare yourself for a major
earthquake you can prepare yourself for
just about all the other stuff that can
come down the road. Again
our last two presidentially declared
disasters in the metro area were
snowstorms. We have power outages . W have wind storms. For a lot of people they are
not sufficiently resilient to withstand
48 hours without power. They don't have
much in the way of a reserve for
medications or consumable medical
supplies like home oxygen.
Again we see this in every single event.
So trying to channel that concern
into productive action rather than
fretting. If you want probabilities, Chris
gave you a pretty good set of numbers.
Tom gave you some numbers. More it's, we
know it's going to happen. We can't say
it's going to happen tomorrow, but we've
seen all sorts of other things happen storms
power, etc so they will continue to
happen. Yeah, this is Chris. I'd
agree completely with Jeff is channel
that worry energy into some action
and you know we're in the awkward
position of having built our society on
top of a grenade essentially and not and we didn't know it, and so and now
and now we do so we can translate that
at first is fear and worry into
some simple actions - taking care of
yourself and your family
you know looking at how your house is
built, looking at supplies you may have,
thinking about maybe a gas shutoff valve
to keep your - because often houses burn down in
earthquakes rather than have structural
damage, and then beyond that think about
the building's people think about the
building's you work in and if it
looks like a building you work in is a
collapse hazard then maybe if you
mobilize your fellow employees and
managers and whatever to try to make the
company move towards a retrofit. And this
is sort of a bottom-up approach and we
live in more or less a bottom-up society
and that's the way things happen.
Channel the energy in to
positive steps and and people can
educate themselves and learn these
things. They're not difficult to find
information on, and look at examples
of other places and what what they've
done. So this is a long this is going to
make the Pacific Northwest resilient and
make it perform as well as Japan does in
an earthquake this is gonna take some
time. They have a they have a thousand
year head start on us after all.
And so it's going to be a long sustained
effort but worry doesn't help that much.
I don't worry about earthquakes. I live
here and but I do take some simple
actions to
mitigate that risk and anywhere we
live there's going to be something you
have to consider - hurricanes, floods,
tornadoes, whatever what have you and
people take relatively simple steps to
to channel that worry into action. This
is Tom. I agree with both Chris and Jeff
and their sentiments and I think in many
cases once we're aware of hazards
and we can think through the
consequences of the hazards to our
businesses and our daily lives and in
many cases businesses recognize
that you know if they're not prepared
for this event they're going
to lose business or go out of business.
You know if the port facilities are
closed you know the port's shipping
continues they just they use the port
that's available, and so the port
business will go elsewhere. And so being
prepared is you know it's a good
business decision. It will help you
maintain your business and the viability
of it following the event. So there's lots
of lots reasons to prepare for
earthquakes that other than just
surviving them. I think some people have
a sense that earthquakes are great
killers, and that's not really the case 
in the U.S. Relatively few people are
even injured in earthquakes but it's the
economic loss that can be quite damaging
and so whatever we can do to help
minimize not only our loss of life
and numbers of injuries, but our property
damage and our ability to conduct
business will speed our recovery as well.
Thanks and we have one other question
here. What will the impact of co-seismic
landslides in a major Cascadia
earthquake be? I can start and I imagine
Tom will have comments as well.
Landslides are really common in the Pacific
Northwest. We get them every winter and
so a lot more will likely be triggered
by any version of the Cascadia
earthquakes. And since we have a coast
range with mountain passes where most of
our access to the coast is on roads
through these passes, there's a
pretty strong chance that most of the
roads to the coast will be closed for
some period of time during a
Cascadia earthquake. And so as Jeff
mentioned in the Oregon resilience plan,
you know those the chances of that and
the time to recover were outlined
in that report and in some cases it's
quite a long time. We also have a number
of bridges that are likely to go down at
the same time. So you know what we
what we tell people in Oregon
is that there the coast may well be cut
off for quite some time in terms of road
transport and access to those areas will
be mostly by air and by sea for some
some period of time, and the landslides
will occur inland as well in Seattle and
and Portland and the most of the
past ones have been mapped out but these
are future landslides from
a future earthquake may not 
happen in places that are obvious are
well known either. At some time in the
past even very large landslides may have
blocked the Columbia River for example.
There's a location called the Bridge of
the Gods that was a landslide that
backed the Columbia River up for 20 or
30 miles. 
So something very dramatic
like that is a remote but a
possible outcome as well. This is Tom. Yeah
it's fair to say that
landslides there will be lots of
landslides caused by this big subduction
zone earthquake. How fast it'll take to
move the landslide debris out of the way
and restore our road to the service, I'm
not so aware of, but generally my
experience in California is that the
landslides we get are cleared pretty
quickly following an earthquake in a few
days, but we may not be dealing with the
numbers of landslides that we might get in
a Cascadia subduction zone
earthquake in the coast ranges. Great.
Thank you so much. Well that's all the
time we have for questions for today's
webinar. Thank you very much Chris, Jeff
and Tom for presenting today and also
for staying on a little longer to answer
all the questions. And this concludes our
webinar for today.
