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government agencies but not directly to general public, responders, the
media, or the international community.
Furthermore, while each of these tools/systems relies on basic earthquake
parameters to estimate losses, the modeling assumptions and the method-
ologies implemented within the tools in order to constrain both earthquake
ground shaking and to perform exposure and vulnerability analyses vary
greatly. It is thus quite challenging to test the results of one tool or system
against another for the same earthquake or scenario since many of these
tools and models output different loss metrics at different resolutions.
Despite these differences, these tools and systems (some of them being
global and others being region-specifi c) represent important and much
needed development in the fi eld of rapid loss estimation. It is for these
reasons above that we embarked on the PAGER project, which was meant
to provide an open framework for data collection and dissemination, hazard
and loss algorithms, intermediate products to be used by others (namely
ShakeMap), and the resulting loss estimates. Documentation of these data
and models are provided online and in the peer reviewed literature.
31.3
Prompt Assessment of Global Earthquakes for
Response (PAGER) system development
Following the 2004 Sumatra earthquake (
M
w
9.1) and tsunami, the USGS
began the development of a new system PAGER. In 2006, with a prototype
PAGER system, the USGS started issuing population exposure results for
all signifi cant global earthquakes (
M
w
3.5 and above in the United States,
and
M
w
5.5 and above globally), providing both estimated intensities as well
as estimates of populations exposed to each shaking level. Events with large
population exposures at higher modifi ed Mercalli intensities (MMIs) clearly
warranted attention. Yet, the differences in vulnerabilities given these expo-
sures were not specifi cally addressed. Finally, in September 2010, the
PAGER system began publicly releasing impact-based alerts (for likely
casualties and economic losses) following signifi cant earthquakes around
the globe by incorporating empirically based losses. Publicly providing
fatality and economic loss estimates required a new way of communicating
uncertain losses; therefore, the USGS introduced an earthquake alert scale
(Wald
et al.
, 2011).
At the core of the PAGER system there are four modules that are inte-
gral to the operational earthquake impact estimation (Fig. 31.1). The fi rst
module consists of earthquake source characterization. This operation is
dependent upon retrieving earthquake source parameters that are pro-
duced by National Earthquake Information Center (NEIC) following large
earthquakes, and regional seismic networks in some areas of the United
States. These include estimation of the earthquake magnitude, location,
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