PrepTalks: Dr. Robert Chen “Who is at Risk? Rapid Mapping of Potential Hazard Exposure”


I’m pleased to have the opportunity to
come talk to you today about thinking about who’s at risk and how one can use
new tools to do rapid mapping of population exposure or potential
population exposure. I don’t have to remind you that last year was a pretty
intense year on a number of fronts. we had this unusual hurricane season, but
also fires and earthquakes and all sorts of other disasters. Of course an
interesting thing about hurricanes that I don’t have to tell you is it there’s a
extended period of time when you’re sort of wondering which way is the hurricane
going to go, and at various points in times the entire Atlantic Coast
population was potentially at risk of being hit, but of course in actuality
only a small proportion of those people actually experienced the landfall or
associated wind and flooding damage. So as most of you I’m sure working the
field have a inherent understanding of who and where the population centers are,
but of course it’s always good to see it on the map and to be able to explain
where population centers are and who’s vulnerable to external audience or to
local and regional decision makers. So having data first off on just population
distribution is useful from that perspective, and this kind of data
can be used of course both by managers and by the press and members of the
public but one also might be interested in more details. Not just where
population lives, but you know where are the elderly,
what’s the housing stock that they live in that might be more vulnerable to a
storm or certain kinds of damage; where are the urban areas in the coastal zone
that’s low in elevation; a lot of different data may be relevant to
identifying specific populations, and of course infrastructure is really critical.
Transportation infrastructure things that certainly have secondary impacts if
they are affected by a severe storm, dams power plant,s even in the case of Puerto
Rico there was a decommissioned nuclear power plant there, cultural sites, of
course hospitals, and other emergency facilities. These are important
infrastructure and of course within the U.S. government there are groups, the
Highfield Group and others, that collect data on infrastructure, geospatial data,
and make it available. Of course, I bet many of you, if you were involved,
probably also use Google Maps or other tools site view to get a sense of what’s
actually there. But so putting, getting access to this data and putting it
together is an important way of understanding the context of any
disaster that’s imminent or after its occurred. But more than looking at pretty
maps, you’d also like to be able to give get a quick estimate of, first off, how
many people is that, so if you have a National Weather Service warning area,
this is about a week ago in Michigan, it’s a little polygon that appears from
the Weather Service when there’s a River outlook flooding. You know wouldn’t you just
like to be able to go to the map and see well how many people actually live
in that and watch it as it moves across the landscape and get that total. Or if
you see an event like this, fires in Southern California, wouldn’t you like to
be able to kind of get a sense, “Well is that a really heavily populated area
where those fires are occurring or not. You know where is the plume that’s
aerosol optical depth from a NASA MODIS satellite showing overlaid with the
extent of fires detected by satellite, and then the population. So being able to
put these different kinds of data together to get a sense of what the risk
is where is the potential associated effects of disaster is helpful. There was
just a earthquake off the coast of Alaska, and of course there was concern
about a tsunami. One question you know how many people are within a certain
distance of the epicenter, but in the case of a tsunami you might want to
refine that query to kind of understand how many people live along the coast
that could conceivably be hit by a wave. So you know the ability to go from a
simple query like a circle to a more complex spatial query like a polygon
that you just draw in a client allows you to make a somewhat more focused or
get a somewhat more focused answer. Now these are not as accurate as if you had
to as if you used a geospatial information system went and
downloaded it and made the query in the tool but remember only GIS experts can
do that. They can you know it takes some time; they can’t do it fairly
instantaneously through a simple interface. This tool that I’m talking
about, which is developed by our center, is an interactive map. It also accesses
data from a range of sources. One of the ones here is called EOnet; it comes from
the NASA earth data website and allows you to look at historical hazard events
and for example you can see tracks of prior severe storms and hurricanes or
fires and allow you to do a little bit of retroactive analysis. And the way in
which you can think about these tools, you know, would be we were actually
interested in feedback. Here’s a case where there was a Weather Service
warning in an area along the i-10 corridor between two major cities, so
you’re not just worried about the direct impact of that hazard on a point but what how
important is that point for example and disrupting a major transportation
quarter. We’re sitting here in the DC area, how many people actually
live inside the beltway and what would happen if an event occurred here. As we
as you think about these data, what one wants to start looking at is the way in
which hazard occurrence may interact or or have the way in which they may not be
totally independent of the where people live, and so one obvious question after
many of the recent hurricanes is, for example, are the elderly particularly
concentrated in areas of flooding. Some of my colleagues took a look at this
using the type of data I’ve been showing and and didn’t find a correlation in the
Houston area between where the elderly live and the flooding. But it’s a
important question to ask and certainly one that’s relevant in disaster response.
And of course as we move not only from looking at potential exposure to actual
impacts there are opportunities to bring in new types of data. This I’m sure
you’ve seen after Puerto Rico was data from
a relatively new satellite and an instrument called VIIRS which looks at
nighttime lights and can detect the changes essentially in the electrical
grid before and after Hurricane Maria. And we’ve been working with Miguel Ramon
at NASA Goddard to try to improve this as an indicator and then incorporate
this into kind of a near real-time service to make it available as a as a
useful tool for measuring impact. You can actually already see this data in NASA’s
worldview client in which you see our original population data fading into the
night time lights data so you can get a sense of where there are lights, where
there are people or not. You know it’s nice for a center like ours to build a
client not everybody will come to your site and try to use a client what’s more
important is how do you get the data out and into tools that the community
already uses. So for example we’ve been working with a tool called GeoCollaborate operated by the All Hazards consortium which is an industry
consortium that helps in utilities coordinate fleet movements after a
disaster. So after all the hurricanes actually I guess there were two phases
of intervention in Puerto Rico where utility trucks were shipped to Puerto
Rico in January, and those trucks have to go between states, they have to deal with
issues related to weigh stations, and finding housing for the crews, and
dealing with blocked roads, so the all-hazards consortium has developed
this tool called GeoCollaborate which helps pull that information together in
a collaborative way. What we did this past fall is add this little button here
on the bottom left which is an icon with people, and the point is it
accesses the data service that I showed you previously in order to do something
like draw polygon around part of Puerto Rico and return the estimated population.
So it’s just a simple way of making the same type of query through a tool that
industry and others use and get access to you know just a very basic piece of
information about population exposure. Of course not everybody using this is
sitting at a desk with a web browser. How do you give this kind of capability to
people out in the field who might be using mobile apps and also think about
how to take advantage of the location services that you get when you’re in a
mobile platform? So you might be at a point where you want to know the
distance away from a facility or from an event, and of course if you go to Google
Maps, you’ll just get the road distance not the line of sight distance. So this
is a very simple query that just allows you to say, “well how far am i away from
say a nuclear power plant.” Or as with the case of the earthquake, you know, what are
the how many people are living within a particular distance of the epicenter of
an earthquake or some other event. And you may also want to quickly pull up
information about those facilities, so it happens we have access to a nuclear
power plant database that pulls information in from the International
Atomic Energy Agency and that gives you sort of detail, the imagery of the
particular site. There’s actually operating information about it and then
you can do that little query about how many people live within a particular
radius. That’s where I live, where you know it matters whether my kids’
school was within 10 kilometers or 10 miles are out and I have one kid in, and
one kid out which meant they got evacuated to totally different places, but that’s important information to know f you’re in the field. And just to start
wrapping up, there are a bunch of other kinds of data that may be relevant, which
some of the scientific community is producing and part of our interest is
trying to figure out what information is really relevant to the user to; the
Emergency Management community, and what could be folded in. So for example, we
recently released a data set also developed at NASA Goddard which is about
the percent impervious surface in any particular area based on 30 meter
resolution Landsat data, and yeah one of the questions is, “What is that, how can
that be useful for people who are thinking about flood response?” and you
know how much asphalt in an area might affect flood levels for example, or does
it have to be plugged into hydrologic model that quickly uses that information
to estimate what the the flood levels might be. And so on that vein we we’re
recently also developed a global data set which has estimates of not just the
total population but specific age groups and the sexes of area males versus
females because those are important in thinking, of course, about vulnerability.
If they’re excessive number of elderly or children or women of childbearing age
those can be important in thinking about vulnerability to disaster. In the U.S.
census, of course, there are many useful variables thinking both about
individuals and households and other kinds of differences that may be
important in certainly in planning. One of the things we’re doing with the New
York State is mapping literally every building in the
state trying to detect using imagery whether the roof is peaked or flat but
useful in integrating into a decision support tool that may be interested in
potential flooding impacts or wind or other kinds of damage. And of course we
have a Android version of the mobile app that I mentioned under development. So
just to summarize you can find these mapping tools on our NASA SEDAC website.
They are free, open to the public. You can also go directly to them or use that
QR code to go directly to the iTunes Store and download it. And you can also
see the fleet response working groups geo collaborate tool they keep a record
of many of the recent events and some of the data that were delivered and how
these were used by industry. and of course, you can go to the NASA site to
find a whole range of data from the data systems that take data and deliver it to
users from satellites. We’re certainly interested in feedback on how to make
these tools and services more relevant to emergency managers and hope to be
able to improve them and work with the community to make them more effective.
Thank you

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