Geoscience Reference
In-Depth Information
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Second, the USGS could take a lead to organize a series of workshops to determine
the design tsunami sources. Tsunami sources should be determined for the regional
base without state boundaries. (For example, the Cascadia scenario could be studied
for (overlapped) subregions: north, central, and southern parts of the subduction
zones.) The actual inundation modeling could be conducted by NTHMP members, and
the outcomes of the inundation modeling must be transparent and accessible in the
foregoing virtual repository.
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Alternatively, NOAA could undertake inundation modeling using a community of
models; again, the outcomes would be accessible in the virtual repository. Throughout
the task of inundation modeling, the committee emphasizes that NTHMP members
would continue to be responsible for producing hazard maps that relect local
conditions and needs.
Evacuation Maps
Evacuation maps depict areas that may need to be evacuated in the event of a tsunami
and are designed to be understood and used by at-risk individuals and by local emergency
managers in their evacuation-planning efforts. The committee found it dificult to review prog-
ress made in evacuation mapping since 2006 with regard to the number of maps completed
as well as the quality and the level of coordination of these efforts because of: (1) the lack of a
comprehensive and continuous inventory of available evacuation maps relative to the number
of at-risk communities and (2) inconsistencies in product quality. As mentioned in the previous
section, the most recent tabulation of completed efforts provided by the NTHMP (Table 2.2)
provides no information on the number of communities with evacuation maps relative to the
number of communities with evacuation maps in 2001 or the total number of at-risk communi-
ties. Therefore, the committee cannot accurately assess progress with regard to the numbers of
coastal communities for which evacuation-mapping efforts have been completed.
Although the production of evacuation maps is essential for emergency preparedness and
evacuation planning, the committee observed that efforts to produce such maps vary substan-
tially nationwide. This observation is based on input provided by the NOAA Tsunami Program
and NTHMP members during the course of the committee's review, as well as information
gathered via an online search for tsunami evacuation maps (see Appendix D for a list of evacu-
ation maps). Oregon and Hawaii have tsunami inundation zones for their entire coastlines and
evacuation maps for all coastal communities, and are currently updating their evacuation maps
in select communities. Although most evacuation maps currently available only delineate a
single tsunami scenario, the Oregon Department of Geology and Mineral Industries (DOGAMI)
has recently created a new type of evacuation map that includes near- and far-ield tsunami
inundation scenarios (Figure 2.1). Washington lacks a statewide tsunami inundation zone but
has evacuation maps for all communities on the open-ocean coast (e.g., Clallam, Jefferson,
Paciic, and Grays Harbor counties) and for several Puget Sound communities (e.g., Whatcom
County) that are threatened by tsunamis generated by the Cascadia subduction zone and
