Geoscience Reference
In-Depth Information
Hazard Maps
The development of tsunami hazard maps in the United States has had three distinct his-
torical phases: (1) before the establishment of the NTHMP in 1995; (2) between the establish-
ment of the NTHMP in 1995 and the Tsunami Warning and Education Act in 2006; and (3) after
the Tsunami Warning and Education Act of 2006. Prior to the development of the NTHMP in
1995, tsunami maps were only available in Hawaii and Alaska. With the creation of the NTHMP,
funding became available for tsunami inundation modeling and mapping in the ive Paciic
states. Efforts were implemented within each state, with the intention of building local model-
ing capacity, improving tsunami awareness, leveraging state funds, and creating local stake-
holders that could sustain tsunami efforts through periods of low federal funding.
Progress in
hazard mapping efforts as of 2001 was signiicant but not uniform across the states (Table 2.1;
González et al., 2001).
Following the 2004 Indian Ocean tsunami, demand by coastal communities for hazard
and evacuation maps increased, and several NTHMP members began to produce next genera-
tion maps at much higher resolution (Barberopoulou et al., 2009; Priest et al., 2009). The most
recent tabulation of completed mapping efforts provided by the NTHMP (Table 2.2) yields
little detailed information and no ability to compare the current inventory to the 2001 inven-
tory; hence, it is dificult to assess progress since 2001 with regard to the numbers of coastal
communities for which hazard mapping efforts had been completed. In general, however, it
appears there has been some progress (yet not uniform as was the case in 2001) in mapping
efforts across the NTHMP. Many NTHMP members cite a lack of resources as one of the key
challenges to making progress in mapping inundation zones. Despite an increase in demand
for tsunami hazard maps in the wake of the 2004 Indian Ocean tsunami, federal support to un-
dertake mapping efforts did not increase and, in contrast, some states actually received fewer
inancial resources thereafter (Figure 2.3).
The 2006 Tsunami Warning and Education Act (P.L. 109-424) represents a new phase in
tsunami inundation and hazard mapping because of mandates and recommendations in the
public law. In response to language in the 2006 Act and a report by the Government Account-
ability Ofice (2006) to strengthen mapping efforts, the NTHMP formed a Mapping and Model-
ing Subcommittee (MMS) to coordinate its efforts. Additional language in the 2006 Act calls on
the NOAA Tsunami Program to “provide tsunami forecasting capability based on models and
measurements, including tsunami inundation models and maps” (P.L. 109-424, Section 4(b)(4))
and for the NTHMP to “use inundation models that meet a standard of accuracy deined by the
Administration (i.e., NOAA) to improve the quality and extent of inundation mapping … in a
coordinated and standardized fashion to maximize resources and the utility of data collected”
(P.L. 109-424, Section 5(c)). The remainder of this sub-section discusses current efforts in rela-
tion to this new language.
Tsunami generation, propagation, and inundation are solely physical problems and do
not recognize political borders. However, the committee found (contrary to the 2006 Tsunami
Warning and Education Act) that the development and use of inundation modeling is not
occurring in a standardized fashion across the NTHMP and that each NTHMP state member
