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pdfNational Flood Insurance Program
Community Rating System
CRS Credit for Mitigation of
Tsunami Hazards
2006
A community interested in more information on obtaining flood insurance premium
credits through the Community Rating System (CRS) should have the CRS Application.
This and other publications on the CRS are available at no cost from
Flood Publications
NFIP/CRS
P.O. Box 501016
Indianapolis, IN 46250-1016
(317) 848-2898
Fax: (317) 848-3578
[email protected]
They can also be viewed and downloaded from FEMA’s CRS website,
http://training.fema.gov/emiweb/CRS/index.htm
Contents
Section
Page
Introduction ................................................................................................ 1
Background on Tsunami Hazards ................................................................3
Source Areas .........................................................................................4
CRS Credit.................................................................................................. 9
300 Public Information Activities ......................................................... 9
310 Elevation Certificates.............................................................. 10
320 Map Information..................................................................... 10
330 Outreach Projects.................................................................... 11
340 Flood Hazard Disclosure......................................................... 12
350 Flood Protection Information .................................................. 12
360 Flood Protection Assistance .................................................... 12
400 Mapping and Regulatory Activities ............................................... 12
410TS Additional Flood Data for Tsunami Hazard Areas............... 14
420TS Open Space Preservation in Tsunami Hazard Areas ............ 15
430TS Regulation of Tsunami Hazard Areas.................................. 18
430LZTS Low Density Zoning ...................................................... 22
500 Flood Damage Reduction Activities ............................................. 25
510TS Floodplain Management Planning........................................ 25
520TS Acquisition and Relocation................................................. 25
530TS Flood Protection ................................................................. 25
600 Flood Preparedness Activities ...................................................... 26
610TS Flood Warning Systems ...................................................... 26
References ................................................................................................ 27
Glossary.................................................................................................... 29
Activity Worksheets
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Mitigation of Tsunami Hazards
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INTRODUCTION
The Community Rating System (CRS) rewards communities that are doing more than
meeting the minimum requirements of the National Flood Insurance Program (NFIP) to
help their citizens prevent or reduce flood losses. The CRS also provides an incentive
for communities to initiate new flood protection activities. The goal of the CRS is to
encourage, by the use of flood insurance premium adjustments, community and state
activities beyond those required by the NFIP to
•
Reduce flood losses, i.e.,
o protect public health and safety,
o reduce damage to buildings and contents,
o prevent increases in flood damage from new construction,
o reduce the risk of erosion damage, and
o protect natural and beneficial floodplain functions.
•
Facilitate accurate insurance rating, and
•
Promote the awareness of flood insurance.
The CRS includes 18 creditable activities, organized under four categories:
300—Public Information
400—Mapping and Regulations
500—Flood Damage Reduction
600—Flood Preparedness.
Credit points are based on the extent to which an activity advances the three goals of
the CRS. Communities are invited to propose alternative approaches to these activities
in their applications.
The Federal Emergency Management Agency (FEMA) and many communities in the
United States have long recognized that the mapping and regulatory standards of the
NFIP do not adequately address all of the flood problems in the country. In particular, a
number of “special” flood hazards deserve attention. They include
•
Ice jam flooding,
•
Flooding adjacent to closed basin lakes,
•
Mudflow hazards,
•
Flooding affected by land subsidence,
•
Uncertain flow path flood hazards,
•
Coastal erosion, and
•
Tsunamis.
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This publication discusses the credits provided by the CRS for mapping and
management of tsunami hazards. The other hazards are addressed in the publications
Special Hazards Supplement to the CRS Coordinator’s Manual and CRS Credit for
Management of Coastal Erosion Hazards. All are supplements to the CRS
Coordinator’s Manual, and include additional Schedule sections and Commentary.
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BACKGROUND ON TSUNAMI HAZARDS
A tsunami is a series of long waves
generated by a sudden displacement of a
large volume of water. Tsunamis are
triggered by submarine earthquakes,
submarine volcanic eruptions, underwater
landslides or slumps of large volumes of
earth, meteor impacts, and even onshore
slope failures that fall into the ocean or a
bay.
Tsunamis are typically classified as either
local or distant. Locally generated
tsunamis have minimal warning times and
Source: NOAA News Photo.
may be accompanied by damage resulting
from the triggering earthquake such as
ground shaking, surface faulting, liquefaction, or landslides. This leaves few options
except to run to high ground. Distant tsunamis may travel for hours before striking a
coastline giving the community a chance to implement evacuation plans.
In the open ocean, a tsunami may be only a few inches or feet high but can travel with
speeds approaching 1000 kilometers (about 600 miles) per hour. As a tsunami enters
the shoaling waters near a coastline, its speed diminishes, its wavelength decreases, and
its height increases greatly. However, the first wave usually is not the largest. Several
larger and more destructive waves often follow the first one.
The configuration of the coastline, the shape of the ocean floor, and the characteristics
of advancing waves play important roles in the destructiveness of the waves. Offshore
canyons can focus tsunami wave energy and islands can filter the energy. The
orientation of the coastline determines whether the waves strike head-on or are
refracted from other parts of the coastline.
A wave may be small at one point on a coast and much larger at other points. Bays,
sounds, inlets, rivers, streams, offshore canyons, islands, and flood control channels
may cause various effects that result in greater damage than many people would expect.
It has been estimated, for example, that a tsunami wave entering a southern California
flood control channel could reach a mile or more inland, especially if it enters at high
tide.
The first visible indication of an approaching tsunami may be recession of water (draw
down) caused by the trough preceding the advancing, large inbound wave crest. Rapid
draw down can create strong currents in harbor inlets and channels that can severely
damage coastal structures due to erosive scour around piers and pilings. As the water’s
surface drops, piers can be damaged by boats or ships straining at or breaking their
mooring lines. The vessels can overturn or sink due to strong currents, collisions with
other objects, or impact with the harbor bottom.
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Conversely, a rise in water level may be the first indication of a tsunami. The
advancing tsunami may initially resemble a strong surge increasing the sea level like
the rising tide, but the tsunami surge rises faster and does not stop at the shoreline.
Even if the wave height appears to be small, three to six feet for example, the strength
of the accompanying surge can be deadly. Waist-high surges can cause strong currents
that float cars, small structures, and other debris. Boats and debris are often carried
inland by the surge and left stranded when the water recedes.
Outflow following inundation also creates strong currents, which rip at structures and
pound them with debris, and erode beaches and damage coastal structures. As tsunamis
reach the shoreline, they may take the form of a fast-rising tide, a cresting wave, or a
bore. The bore phenomenon resembles a step-like change in the water level that
advances rapidly (from 10 to 60
miles per hour).
The force and destructive effects of
tsunamis should not be underestimated. At some locations, the
advancing turbulent wave front will
be the most destructive part of the
wave. In other situations, the
greatest damage will be caused by
the outflow of water back to the sea
between crests, sweeping all before
it and undermining roads, buildings,
bulkheads, and other structures.
This outflow action can carry
enormous amounts of highly
damaging debris with it, resulting in
further destruction. Ships and boats,
unless moved away from shore, may
be dashed against breakwaters,
wharves, and other craft, or be
washed ashore and left grounded
after the withdrawal of the seawater.
Damage from the 1960 tsunami in the Waiakea
area of Hilo, Hawaii. The force of the debrisfilled waves bent parking meters. (National
Tsunami Hazard Mitigation Program, 2001, p.
13; Photo from U.S. Navy.)
Source Areas
The earth’s surface is made up of a number of plates that contain large sections of the
continents and ocean basins. These plates may pull apart, slide past, override, or
underride (i.e., “subduct”) one another. Plate boundaries coincide with faults that
produce earthquakes as stress accumulated from the relative movement of the plates is
relieved. The earthquakes, in turn, may produce displacements of the sea floor that can
set the overlying column of water in motion, initiating a tsunami. However, all
submarine earthquakes do not produce tsunamis. It depends on the magnitude of the
earthquake and type of faulting that has occurred.
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The National Oceanographic and Atmospheric Administration (NOAA) issues warnings
of a possible tsunami when an earthquake is located very near or under the sea and its
magnitudes exceeds a certain threshold (currently 6.8 for earthquakes in Hawaii, 7.0 for
Alaska, British Columbia, Washington, Oregon, and California, and 7.5 for elsewhere
in the Pacific).
The most active plate boundaries rim the Pacific Ocean and the Caribbean Sea.
Consequently, this is where most tsunami activity might be expected. This is indeed the
case. Most tsunamis originate in the Pacific “Ring of Fire,” which is the most active
seismic feature on earth.
An estimated 489 cities within the Pacific states of Alaska, California, Hawaii, Oregon,
and Washington are susceptible to tsunamis. As many as 900,000 residents of these
cities would be inundated by a 50-foot tsunami.
Potential Destructiveness of Tsunamis
in the Five Pacific States
(Wallace, 2000, p. 5)
State
Alaska
Cities susceptible
to tsunamis
Population endangered
by a 50-foot tsunami
52
47,000
California
152
589,500
Hawaii
123
131,000
Oregon
60
31,500
Washington
102
96,000
Total
489
895,000
Pacific Northwest
History has demonstrated that most tsunamis affecting the Pacific Northwest (N.
California, Oregon, and Washington) have originated in the Gulf of Alaska (Aleutian
Subduction Zone). There is also geological evidence of significant impacts from
tsunamis originating along the Cascadia Subduction Zone. The Cascadia Subduction
Zone extends from Cape Mendocino in California to the Queen Charlotte Islands,
British Columbia, and its surface trace is but a short distance off the coast.
Historically, the Washington and Oregon coasts have received comparatively minor
damage from Alaskan tsunamis. However, Crescent City, in northern California, has
experienced damaging tsunamis from Alaska and noticeable effects from a tsunami
originating near Chile. A tsunami generated along the near-by Cascadia Subduction
Zone would probably also be very damaging to that community.
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The Pacific “Ring of Fire” is the most active seismic feature on earth. Tsunami waves triggered
by seismic activity can travel across the Pacific Ocean at up to 500 miles per hour, striking
distant coastal areas in a matter of hours. The figure shows the estimated number of hours for
tsunami-generated waves to travel across the Pacific Ocean from Alaska and Chile,
respectively (National Tsunami Hazard Mitigation Program, 2001, p. 6).
Many geo-scientists and emergency managers are concerned about the possibility of an
earthquake along the Cascadia Subduction Zone. Much of the concern is based on the
proximity of the zone to populated coastal areas and the belief that another earthquake
may be due. The average recurrence interval (Glossary) for a Cascadia Subduction
Zone event is approximately 500 years with time between events as little as 200 years
and as much as 1000 years. The last event has been placed about the year 1700.
An examination of sediments along the Pacific Northwest coasts supports the theory
that tsunamis accompanied previous Cascadia Subduction Zone events. At the June
2000 Penrose Conference consensus was reached by the scientific community. This
evidence has been used in support of some tsunami inundation maps.
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Central and Southern California
Communities located on the central and southern California coasts should primarily be
concerned with tsunamis originating from local faulting and submarine landslides.
However, the area has experienced tele-tsunamis from a number of locations including:
•
Alaska peninsula
•
Aleutian Islands (several locations)
•
Chile (several locations)
•
Hawaii
•
Japan (several locations)
•
Kamchatka/Kuril Islands
The San Francisco Bay Area suffered over $1 million in damage from the 1964
tsunami. However, the relative absence of damage tends to minimize tsunami hazard
mitigation activities in Bay Area communities.
Alaska
Alaskan communities are located in a region known to generate or experience very
destructive tsunamis. The region is highly seismic (Aleutian-Alaskan trench) and is also
subject to tele-tsunamis originating in the vicinity of Kamchatka and the Kuril Islands.
Local tsunamis have been produced through faulting, submarine landslides, and surface
landslides into constricted bodies of water (e.g., bays). Twelve destructive tsunamis
have been recorded in Alaska. At least three of these caused significant damage in the
Pacific basin. Hawaii is particularly vulnerable to tsunamis generated in Alaska.
Significant tele-tsunamis have also been recorded from Japan and South America.
Hawaii
Hawaii has a history of being adversely impacted by many tsunamis, generated both
locally and from around the Pacific rim. They are generated locally primarily through
earthquakes and landslides associated with Hawaii’s active volcanoes. However,
relatively few tsunamis are generated locally and destruction from local tsunamis has
historically been confined to one island. Widespread destruction from tele-tsunamis
occurs more frequently – a few times each century. The position of the islands makes
them vulnerable to all the known tele-tsunami sources along the Pacific margin
including all of South America, Alaska and the Aleutian Islands, Kamchatka and the
Kuril Islands, and northern Japan.
It is noteworthy that run-up heights differ throughout the islands. This is to be expected
because of reef protection and the behavior of tsunamis entering confined bodies of
water (e.g., bays and lagoons). Run-ups may be somewhat higher on the side of the
island facing the source zone, but tsunami waves can efficiently wrap around islands
and be destructive on all shores.
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South Pacific
Like Hawaii, the three NFIP communities of Guam, American Samoa (Manua and
Tutuila), and the Northern Marianas (Saipan), are vulnerable to local tsunamis and teletsunamis originating along the Pacific margin. However, unlike Hawaii, the islands are
very near two extremely seismic areas. Guam and Saipan are just west of the Mariana
Trench and American Samoa is adjacent to the Tonga Trench. These two trenches are
active subduction zones and consequently generate earthquakes and tsunamis.
The three island communities have experienced destructive tsunamis dating back to the
mid-1800s (when records commenced). Some of the tsunamis are associated with local
volcanic activity. However, despite their proximity to volcanic areas and subduction
zones, most tsunamis there have originated along the Pacific margin. Places of origin
include Alaska, Mexico, the west coast of South America, Indonesia, and the North
Pacific (e.g., Kuril Islands).
Pago Pago, on the Samoan island of Tutuila, can be singled out as being especially
vulnerable to tsunamis. This is because of its coastal configuration, a V-shaped bay.
Pago Pago has experienced over 40 tsunamis dating back to 1837.
Atlantic Seaboard
Forty tsunamis or tsunami-like waves have occurred in the eastern United States since
1600. Tsunamis were generated by such events as the 1755 Queen Anne’s earthquake,
the Grand Banks event of 1929, the Charleston earthquake of 1886 and the New Madrid
earthquakes of 1811-1812. Tsunami and tsunami-like waves along the East Coast
appear in most cases to be the result of slumping or landsliding associated with local
earthquakes or wave action associated with strong storms. Other sources of tsunamis or
tsunami like waves include volcanic debris falls or catastrophic failure of volcanic
slopes and explosive decompression of underwater methane deposits.
Caribbean Sea
The Caribbean tsunami hazard is partly reflected in the compilation of events over the
last 150 years, where tsunami-related fatalities may have been greater than that in
Alaska, Hawaii, and the U.S. West Coast combined. Practically all known causes of
tsunamis are present in the Caribbean. These include local earthquakes, volcanic
activity, submarine landslides and tele-tsunamis. Puerto Rico and the U.S. Virgin
Islands are situated near a boundary of the Caribbean Plate, a tectonically active region
which will generate tsunamis in the future.
According to Caribbean Tsunami Awareness, a Spanish-French-English outreach
publication, the Lesser Antilles (e.g., the Leeward Islands southeast of Puerto Rico) is
the most likely source of a Caribbean-wide tsunami disaster. The dome of the active
volcano at Monteserrat is growing, which suggests a possible landslide-generated
tsunami hazard. In addition, the submarine volcano, “Kick’em Jenny”, poses a threat to
all of the islands in the eastern Caribbean. This volcano lies about 8 kilometers off the
north coast of Grenada.
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CRS CREDIT
The hazards associated with tsunamis must be dealt with at the community level using
all of the tools used in conventional floodplain management. Under the CRS, these
tools are organized under four general series of credited activities:
• Informing the public and specific populations, about the hazards (300 series)
• Mapping and regulation of the hazard areas with recognition of the unique
problems associated with the hazards (400 series)
• Special structural and nonstructural efforts to solve existing problems (500 series)
and
• Special emergency preparedness efforts that recognize the particular problems
associated with these hazards (600 series).
This section reviews the proven mitigation measures for tsunami hazards addressed in
this publication. In some cases, CRS credit is provided for an activity in the CRS
Coordinator's Manual. In other cases, particularly in the 400 series, special credit is
provided in this publication. For those credits, this document is a supplement to the
schedule and commentary in the CRS Coordinator's Manual and the same formatting is
used. The special hazard credit points calculated under this publication are added to the
regular credit points in the CRS Coordinator's Manual.
A community’s tsunami hazard management program may include activities that are not
eligible for CRS credit. For example, post-disaster recovery and mitigation policies
might require damaged areas to be redeveloped with new street patterns to
accommodate the clustering of structures away from the high hazard area.
300 Public Information Activities
People living on the coast usually do not start worrying about tsunamis until their
property or home is visibly threatened. At that point, their choices are more limited
than they would have been if the tsunami hazard had been considered before the
building was located on the site.
Because the flood hazards associated with special hazards are different from “normal”
flood hazards, there are special needs for public education. Property owners and
developers must be made aware of the hazards and the methods needed to mitigate
them.
A sustained public outreach program is needed to inform coastal populations and to
institutionalize tsunami preparedness and mitigation. Such a program should encourage
consistent information between local government and the community at risk. Innovative
approaches should be encouraged at many different levels.
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There are several ways to provide this information, including
• Newsletter and newspaper articles,
• Signs posted in the hazardous areas,
• Brochures and booklets on the hazards and what can be done,
• Evacuation maps,
• Booths at shopping malls,
• Presentations to civic associations or neighborhood groups,
• Providing information on the location and severity of the hazard areas to inquirers,
• Putting references on the hazard and protection measures in the public library and
on websites, and
• Providing technical assistance to property owners.
Communities can use brochures, single-page instructions, periodic warning system
tests, electronic and print media information, signs, and emergency response exercises
to maintain awareness and instill effective response behavior. Some of this information
should be directed towards special institutions, such as schools, hospitals, and
convalescent-care facilities, and non-English speaking community members. Because
of seasonal tourism in many coastal communities, some provide information especially
for tourists.
310 Elevation Certificates
FEMA elevation certificates, which are required for the purchase of NFIP flood
insurance, and which must be maintained by CRS communities, must be based upon the
current FIRM for the community, and they must be completed using the flood
information from the FIRM and the corresponding Flood Insurance Study. There is no
requirement to maintain elevation certificates outside the Special Flood Hazard Area
(SFHA).
This means that if a community has mapped areas with tsunami hazards, and it is
regulating areas outside the SFHA, and/or its regulatory flood elevation is higher than
that shown on the FIRM, everyone must still use the data from the FIRM for the
purpose of filling out the elevation certificate.
320 Map Information
Many communities provide inquirers with flood information from their Flood Insurance
Study and FIRM. Some use this opportunity to explain local regulations, including their
tsunami hazards and tsunami management requirements. This provides the inquirers
with a more complete picture of their coastal hazard and the importance of regulations
as property protection measures. Notifying people that they are in flood and tsunami
hazard areas can also motivate them to purchase flood insurance and/or undertake
property protection measures.
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Providing information from the community’s Flood Insurance Rate Map (FIRM)
provides many benefits to residents, businesses, real estate and insurance agents,
lenders and those interested in purchasing, developing or repairing property. CRS credit
is provided for advertising this service and for providing information as described in
the CRS Coordinator’s Manual under Activity 320.
If the community is receiving CRS credit for mapping and regulating its tsunami
hazard, the map information service must include telling inquirers if the property in
question is mapped as a tsunami hazard area. The community must also disclose any
tsunami hazard regulatory requirements for developing the property. This can help
property owners and potential buyers better understand the natural hazards risks of a
particular location. Understanding these risks can help property owners and builders
identify and evaluate potential property protection measures.
330 Outreach Projects
This activity provides credit for newsletters, mailings, presentations, booths, brochures
and a host of other means of getting the word out to the public or target audiences, such
as builders or school children. Credit for some of the elements is based on covering
topics such as “flood hazard,” “flood hazard map,” “flood safety” and “property
protection.” These topics should include information on the tsunami hazards, in
addition to the flood hazard mapped on the Flood Insurance Rate Map.
A magnet card designed to foster family preparedness for tsunamis.
One of the elements in Activity 330 provides 100 points for developing and
implementing a public information program strategy. The community identifies its most
important public information needs and identifies the best way to meet those needs. The
strategy could focus on tsunamis, if the strategy team determines that that is as
important as or even more important than “normal” flooding. The full credit of 100
points would still be provided.
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340 Flood Hazard Disclosure
The CRS provides credit when real estate agents disclose information on a property’s
flood hazard to prospective buyers. More credit is provided if the disclosure includes
other hazards, such as tsunami hazards. State or local mandates for sellers, landlords or
developers to disclose these hazards can receive credit. If real estate agents don’t
actually disclose a property’s hazards, but provide a handout advising potential
property buyers about what to look for and what questions to ask, additional points are
provided.
350 Flood Protection Information
Under Activity 350, communities receive credit for putting flood protection information
in their public libraries and on their websites. These materials should cover all known
flood related hazards, including tsunami hazards and property protection measures.
Additional credit points are specifically provided if the library has references on
tsunami hazards provided they are present in the community. This CRS supplement can
be cataloged in the library to receive that credit.
The community or the librarian should also review the references at the end of this
supplement to identify additional documents that would be helpful locally. Some of the
websites mentioned in this publication could also be good links for the community’s
website coverage of its tsunami hazards and ways people can protect themselves and
their property.
360 Flood Protection Assistance
The other activities in this series advise people to learn more about flood insurance and
flood protection. The objective of this activity is to provide interested property owners
with technical information on the tsunami and flood hazards at their property, with
advice on tsunami and flood protection measures, and information on qualified
contractors.
Floodplain residents are more likely to undertake activities to reduce flood and tsunami
hazards to their property if reliable assistance is available locally. The CRS provides
credit if a local government provides technical advice to interested property owners and
publicizes that this service is available.
400 Mapping and Regulatory Activities
FEMA and many communities in the United States have long recognized that the
national mapping and/or minimum regulatory standards of the NFIP do not adequately
address the problems of special hazards. Since these special hazards have the potential
for extraordinary flood damage, it is important that communities deal with these
hazards in ways that go beyond the minimum NFIP standards.
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Tsunami Hazard Mapping in Oregon
The five Pacific states have undertaken tsunami mapping projects. The Oregon
project was undertaken to help implement Senate Bill 379 passed in 1995. The
statute limits construction of new essential facilities and special occupancy
structures in tsunami flooding zones. A line marking inundation from the highest
run-up, which was also most consistent with the prehistoric tsunami data, was
adopted to implement the statute.
The entire Oregon coast is now mapped and selected areas have been and will be
mapped in greater detail. The inundation maps were produced by modeling the
deformation from an earthquake, numerically simulating the resulting tsunami
waves, and mapping the maximum inland flooding limit. The first two steps were
done by computer methods. The third step was accomplished chiefly by inference
using professional judgment and available topographic data.
The mapping project addresses the simultaneous uplift and subsidence of the sea
floor accompanying undersea earthquakes along the Cascadia Subduction Zone
fault system. Numerically simulated run-up elevations for scenarios with the
highest and lowest tsunami run-up were used to infer inundation on 1:24,000-scale
topographic base maps.
The State of Oregon, Department of Geology and Mineral
Industries, prepared maps of the state’s tsunami hazards (Priest, 1995).
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In order for a community to protect new development in areas subject to special
hazards, they must have maps that adequately define the hazards and ordinance
language that deals with the specific hazards in those areas.
410TS Additional Flood Data for Tsunami Hazard Areas
Local decision makers need to understand their risk in order to make informed planning
decisions. Tsunami waves generated from near-source or near-shore earthquakes, or
underwater landslides, may vary in impact from those generated by distant subduction
zone earthquakes. Since the inundation projections are intended for emergency and
evacuation planning, in order to avoid the conflict over tsunami origin, inundation
projections are based on worst-case scenarios.
Inundation maps save lives by providing information ahead of time about the potential
for tsunami impact in certain areas. They enable communities to better plan safe egress
routes. The maps may also serve as a catalyst for thought about placing future
development, especially critical facilities, in projected inundation areas.
Credit for mapping tsunami hazard areas for management purposes is provided under
this activity. Credit for the regulation of new development in mapped tsunami areas is
provided in Section 430TS. Areas for which tsunami hazards regulation credit is
requested may be within the SFHA or outside of it.
411TS Credit Points
Mapping tsunami-prone areas (MTS) (Maximum credit: 50 points)
a. Prerequisites for mapping credit:
1. The area mapped must be subject to tsunami-related development
regulations that receive at least 20 points (after the impact adjustment)
under Section 420TS and/or Section 430TS.
2. The map was prepared based on a scientific study to determine the level
of tsunami flooding. The FEMA Regional Office must state, in writing, that
the study is acceptable for CRS credit.
b. MTS = Up to 50 points for mapping the tsunami runup area. Credit for
mapping the tsunami hazard area is:
1. 50 points for mapping areas outside of the SFHA,
2. 50 points for mapping areas in the SFHA where the tsunami regulatory
elevation is higher than the BFE on the FIRM, or
3. 20 points for mapping areas in the SFHA where the tsunami regulatory
elevation is lower than the BFE on the FIRM.
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Areas subject to tsunami hazards for which credit is requested may be within the
Special Flood Hazard Area (SFHA) or outside of it. There is no mapping credit without
relevant regulations.
413TS Credit Calculation
Tsunami Hazard (Maximum Credit: 50 points)
c410TS = MTS
414TS Credit Documentation
The community must provide the following:
a. A map that shows the areas subject to tsunami hazards and the other
floodplains (including the SFHA) in the community. If only a small area of the
community is mapped for special hazards, only the SFHA in that area need
be shown on the map.
b. A description of the method used for the mapping that shows that it
reasonably delineates areas subject to tsunami hazards and documentation
that the method is acceptable to the FEMA Region.
c. Credit for 4
10TS is only provided if the mapping is used for land use
regulation to prevent damage from the special hazard. The documentation
required for Activity 420TS (open space preservation based on regulations) or
Activity 430TS will suffice for this prerequisite.
420TS Open Space Preservation in Tsunami Hazard Areas
NOTE : This section is a supplement to Activity 420 (Open Space Preservation) in the
CRS Coordinator’s Manual. Much of the discussion in this section relies on Activity
420. Please read that section before proceeding.
This activity provides credit for having floodprone property within a designated special
hazard area preserved as publicly owned or controlled open space. This credit is in
addition to the credit provided for open space (OS) in Activity 420.
The designation and zoning of tsunami hazard areas for open space uses as agriculture,
parks and recreation, or natural hazard areas is recommended as the first land use
planning strategy to consider. This strategy is designed to keep development at a
minimum in hazard areas and to keep insurable buildings out altogether.
A second strategy is to acquire tsunami hazard areas for open space uses. Open space
acquisition has several advantages over strictly regulatory approaches such as zoning.
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Acquisition ensures that the land will be controlled by a public agency or nonprofit
entity, and it removes any question about a regulatory taking. The primary disadvantage
to acquisition is cost.
Open Space Tsunami Protection
Zoning and land use ensure that sites are safer. Hilo, Hawaii did not rebuild a
neighborhood in its tsunami impacted area but instead built a memorial with open
space for people to enjoy but not inhabit. A school at Laupahoehoe was relocated
far uphill after two dozen children and teachers were lost to the 1946 tsunami that
crashed into the original school buildings and surrounding staff homes. The
grounds are now open space with a memorial stone.
421TS Credit Points
Preserved tsunami-prone area open space (TSOS) (Maximum credit: 50 points)
a. Prerequisites for credit:
1. The area must meet the credit criteria for open space preservation in
Activity 420.
2. The area must be included in the tsunami hazard area mapped and
credited under Activity 410TS.
b. TSOS = 50, adjusted by the impact adjustment ratio based on the amount of
the tsunami hazard area that is preserved as open space.
The open space requirement may be met in one of three ways:
(1) Public land such as state and local parks and easements: However, as noted in
Section 403 of the CRS Coordinator’s Manual, there is no open space credit
for federal lands. All portions of city and county parks, forest preserves, state
parks and state forests, and publicly owned beaches or natural areas that are
within the tsunami hazard area may be counted for open space credit, except
paved areas [see Activity 420 of the CRS Coordinator's Manual]. Separate
parcels owned by a school district or other public agency can be counted,
provided there are no buildings on them within the regulatory floodplain.
(2) Preserve land: private wildlife or nature preserves that are maintained for open
space purposes. Examples would be church retreats, hunting club lands,
Audubon Society preserves, and similar privately owned areas that are set
aside and not intended to be developed. A parcel set aside by a developer as a
temporary “preserve” until the area develops is not considered preserved open
space.
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(3) Restrictive development regulations: privately owned lands subject to state or
local regulations that prevent construction of buildings. Credit is only given
for such regulated lands that are vacant at the time of application for CRS
credit. Some examples are setback regulations, natural areas regulations, or
any state or local law that prohibits new buildings from a defined area.
422TS Impact Adjustment
a. Option 1: If the entire area of the tsunami hazard is preserved as open
space, the impact adjustment, rTSOS is 1.0.
b. Option 2: If five or more acres of the tsunami hazard area are preserved as
open space, the impact adjustment, rTSOS is 0.2.
c. Option 3: Where more than 20% of the tsunami hazard area is preserved as
open space the community may calculate an impact adjustment by dividing
the area of tsunami-prone open space (aTSOS) by the area of the mapped
tsunami hazard (aTS).
rTSOS = aTSOS
aTS
423TS Credit Calculation
Maximum Credit for tsunami hazard open space is 50 points.
c420TS = TSOS x rTSOS
424TS Credit Documentation
1. The community must receive credit under 410TS.
2. The community must document that the area where open space credit is
requested is in the tsunami hazard area and meets the open space
requirements of Activity 420 (Open Space Preservation in the Coordinator’s
Manual).
The community must show that the open space areas are in mapped areas subject to
tsunami hazards, as credited under Activity 410TS. The documentation must also show
that the tsunami open space areas meet the preservation criteria for Activity 420.
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430TS Regulation of Tsunami Hazard Areas
NOTE: This section is a supplement to Activity 430 (Higher Regulatory Standards) in
the CRS Coordinator’s Manual. Much of the discussion in this section relies on Activity
430. Please read that section before proceeding.
In areas where it is not feasible to restrict land to open space uses, other land use
planning measures can be used to minimize flood damage. These include strategically
controlling the type of development and uses allowed in hazard areas, and avoiding
high-value and high-occupancy uses to the greatest degree possible. For example, plan
designations and zoning districts can use density restrictions or large-lot zoning to
ensure that only very low-density residential uses are allowed in hazard areas.
Credit is provided for regulating special hazard areas in a manner that recognizes those
elements of the hazard not addressed by the NFIP minimum standards for floodplain
management. This credit is in addition to credit provided for other regulatory standards
under Activity 430 in the Coordinator’s Manual.
431TS Credit Points
Maximum credit for Activity 430TS: 70 points.
a. Prerequisite for credit: T
he regulations must be based on tsunami hazard
mapping credited under Section 411TS.
b. TSR = the total of the following points: (Not to exceed 70 points)
1. 40 points, if new structures are required to be built at or above the
tsunami flood elevation, provided the tsunami flood elevation is higher
than the base flood elevation.
2. 15 points, if regulations prohibit new critical facilities in tsunami hazard
areas unless:
(a) the design can mitigate the vulnerability to such an extent that the
resulting facility will perform as needed; and
(b) the risk is reduced through emergency response measures.
Critical facilities are defined in Section 130, the CRS’ glossary. They include:
• Structures or facilities that produce, use, or store highly volatile, flammable,
explosive, toxic and/or water-reactive materials;
• Hospitals, nursing homes, and housing likely to contain occupants who may not be
sufficiently mobile to avoid death or injury during a flood;
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• Police stations, fire stations, vehicle and equipment storage facilities, and
emergency operations centers that are needed for flood response activities before,
during, and after a flood; and
• Public and private utility facilities that are vital to maintaining or restoring normal
services to flooded areas before, during, and after a flood.
Fire stations, power substations, hospitals, sewage treatment facilities, and other critical
infrastructure generally should not be located in inundation zones. Relocation of these
types of facilities out of inundation areas should be an integral part of any tsunami
mitigation plan.
Where essential service facilities must be located in tsunami hazard areas, they should
be designed or retrofitted to survive tsunami damage. Local governments must be
careful when defining the performance level expected for critical facilities. Building
performance levels describe the expectations of owners, occupants, and regulators
relative to the amount of damage a building could sustain from a tsunami and the
building’s ability following a tsunami event to support the uses for which it was
intended.
Critical facilities should be designed at the re-occupancy or operational performance
level. Buildings constructed to a re-occupancy level should meet the safety level of
performance, but additional precautions should be taken so they can be reoccupied
within a few days to weeks after cleanup, minor repairs, and the restoration of utilities.
This level requires the careful choice of the building location and the use of floodresistant materials.
The most demanding requirements are used to design buildings to meet the operational
level of performance. These buildings should be capable of resisting all expected forces
and hazards. They must also have backup emergency systems and utilities so they can
be used immediately following a tsunami.
Plans for critical facilities that are to be located in hazard areas should include
providing redundant facilities and emergency response measures to lessen the impact of
losing the infrastructure and critical facilities that will be placed at risk.
3. 30 points, for adopting tsunami construction requirements in the Coastal
Construction Manual for new buildings in tsunami hazard areas.
Although a few communities have adopted tsunami resistant building design standards,
the vast majority of coastal communities have not. Design and construction of new
buildings in tsunami hazard areas should address forces associated with water pressure,
buoyancy, currents and waves, debris impact, scour, and fire. Guidance for architects
and engineers in the design for tsunami forces is included in FEMA’s Coastal
Construction Manual, also known as FEMA 55.
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4. 15 points, if regulations require buildings in tsunami areas to be inspected
for compliance with tsunami construction standards by a licensed
professional engineer.
Construction inspection is important to ensure that buildings are constructed according
to the appropriate standards. Independent inspections can be provided in several ways:
1) use of qualified permitting agency staff; 2) use of independent technical experts
retained by the governing jurisdiction; or 3) requiring the owner to use such experts
whose reports would be provided to the governing jurisdiction for review and
acceptance. In some areas, licensed construction inspectors and consulting engineers
provide these services.
5. 15 points, if regulations require substantially improved buildings and
additions to existing buildings in the tsunami area to meet tsunami
construction codes.
This credit complements the credit for regulating new buildings in 411TS.2.a. The
retrofit of existing buildings should be encouraged when the effort will improve
tsunami resistance to a level capable of meeting identified performance objectives, or to
minimize floating debris that can damage nearby buildings. Retrofitting may be
required when substantial modifications are made to existing structures or when there
are changes in building occupancy.
Building codes primarily address new construction; generally, they do not address
renovations and retrofitting comprehensively or in detail. Local building codes should
be amended to fully address risk mitigation in the context of building renovation.
6. 15 points, if hazardous materials are prohibited from the tsunami hazard
area.
Dry docks, refineries, power plants, and other shoreline industrial facilities are of
special concern. Destruction or flooding of industrial facilities can add another
environmental dimension to a tsunami disaster with burning oil, toxic chemicals, and
other hazardous materials. Floating buildings, debris, and boats can crush pipes and
tanks. Protecting industrial facilities with walls and stronger anchoring can help;
however, locating these types of uses outside of inundation zones is the most effective
mitigation technique.
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432TS Impact Adjustment
The area affected by the tsunami regulations must exclude areas designated as
open space that are receiving Open Space (OS) credit under Activity 420 (Open
Space Preservation).
a. Option 1:
1. If new development within the entire area of the tsunami hazard is subject
to the regulations, and no credit was requested for OS in Activity 420, the
impact adjustment is rTSR is 1.0
2. If new development within the entire area of the tsunami hazard is subject
to the regulations, and credit was requested for OS in Activity 420, the
impact adjustment for rTSR = 1.0 – rOS.
As with other regulatory elements, areas for which open space credit (Activity 420) is
requested must be excluded from the area credited for the tsunami regulations.
b. Option 2:
If the tsunami regulations cover only a portion of the tsunami hazard area,
rTSR = 0.25.
c. Option 3:
If the tsunami regulations cover more than 25% of the tsunami hazard area,
the impact adjustment ratio may be computed by dividing the area affected
(aTSR) by the area of the mapped tsunami hazard (aTS). Any area for which
TSOS credit is requested must be excluded from the element’s area
measurements.
rTSR = aTSR
aTS
433TS Credit Calculation
c430TS = TSR x rTSR
The maximum credit for c430TS is 70 points, so if c430TS is greater than 70
points, c430TS = 70. This value is added to SHR in Activity 430. A minimum of
20 points is needed to meet the prerequisite for 410TS.
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434TS Credit Documentation
The community must provide the following documentation:
a. The state or local law or o
rdinance language that adopts the regulatory
standard. The acronym TS must be marked in the margin of the sections of
the ordinance that apply to this activity.
A photocopy of the appropriate pages of the ordinance is sufficient and should be
attached to the activity worksheet. The Chief Executive Officer’s application certification is considered to certify as well that the ordinance or statute has been enacted into
law and is being enforced (see Section 212.a in the Coordinator’s Manual).
The community must have the following documentation available to verify
implementation of this activity:
b. If the community calculates impact adjustment ratios using Option 3
(432TS.c) the Impact Adjustment Map prepared in accordance with Section
403 must be provided.
c. An explanation of the procedures followed for enforcement.
The ISO/CRS Specialist will ask to see permit records for development in the tsunami
hazard area to verify that the regulations are enforced.
430LZTS Low Density Zoning
Credit is provided for zoning areas to keep them substantially open. This credit is
available for undeveloped land within low density zoning districts, as well as for areas
developed in accordance with the density requirements.
431LZTS Credit Points
Areas subject to low density zoning in tsunami hazard areas (LZTS) (Maximum
credit: 50 points)
Credit is given for those portions of the mapped tsunami hazard area subject to
zoning rules that require a minimum of 1 acre per building or unit. Maximum
credit is provided for a 10-acre or larger lot size.
s = the minimum lot size in acres.
LZTSs = 5 x s, for areas with tsunami hazards and with minimum lot sizes of at
least 1 acre.
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The credit for low density zoning is based upon the traditional zoning approach of
setting minimum lot sizes for different zoning districts. The bigger the lot size, the less
dense the development will be in the tsunami hazard area.
432LZTS Impact Adjustment
The area affected by the low density zoning regulation must exclude areas
designated as open space that are receiving Open Space (OS) credit under
Activity 420 (Open Space Preservation).
a. Option 1:
1. If new development within the entire area of the tsunami hazard is subject
to low density zoning regulations, and no credit was requested for OS in
Activity 420, the impact adjustment, rLZTS = 1.0
2. If new development within the entire area of the tsunami hazard is subject
to low density zoning regulations, and credit was requested for OS in
Activity 420, the impact adjustment, rLZTS = 1.0 – rOS.
As with other regulatory elements, areas for which open space credit (Activity 420) is
requested must be excluded from the area credited for low density zoning.
b. Option 2: The community may use the default value if its low density zone
covers at least 5 acres of the tsunami hazard area. rLZTS = 0.2.
The use of Option 2 is limited to one zoning density for at least 5 acres. Communities
with more than 20% low density zoning within their tsunami hazard area may find
Option 3 provides more credit.
c. Option 3: The impact adjustment ratio for each low density zoning district is
computed by dividing the area affected (aLZTSs) by the area of the mapped
tsunami hazard (aTS). Any area for which TSOS credit is requested must be
excluded from the element’s area measurements.
rLZTSs = aLZTSs
aTS
If there is more than one low density zoning district within the tsunami hazard area,
each must be appropriately designated on the Impact Adjustment Map (see Section 403)
and the area of each must be determined in order to calculate the impact adjustments.
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433LZTS Credit Calculation
Maximum Credit for tsunami hazard low density zoning is 50 points.
c430LZTS = ∑(LZTSs x rLZTSs)
434LZTS Credit Documentation
The community must submit the following:
a. The ordinance language that adopts the low density zoning standard. The
appropriate acronym(s) (LZTS1, LZTS5, etc.) must be marked in the margin
of the sections that pertain to the element.
A photocopy of the appropriate pages of the ordinance is sufficient. The CEO’s
certification of the application or modification is considered to include a certification
that the ordinance or statute has been enacted and is being enforced (see Section 212.a).
The community must have the following documentation available to verify
implementation of this activity:
b. If the community calculates impact adjustment ratios using Option 3
(432LZTS.c) the Impact Adjustment Map prepared in accordance with
Section 403 must be provided. Each area listed in Section 431LZTS for which
credit is being requested must be designated on the Impact Adjustment Map
and in the map’s key.
Areas subject to low density zoning are designated as “LZTSs” on the Impact
Adjustment Map (see Section 403), where the “s” designates the minimum lot size (in
acres). An area of 5-acre zoning would be designated “LZTS5”; an area in which one
structure is allowed on a 100,000-square-foot lot would be designated “LZTS2.3”
(100,000 square feet is 2.30 acres).
c. An explanation of the procedures followed for enforcement of the regulatory
standard.
During the verification visit, the ISO/CRS Specialist will need to see site plans and
final plats that will document how the land development criteria or zoning density is
applied. The ISO/CRS Specialist will also visit a sample of new developments to verify
that they have been constructed in accordance with the approved plans.
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500 Flood Damage Reduction Activities
Coastlines have always been a favored location for human settlements. Because of the
attractiveness of coastal locations and the long gaps between devastating tsunami
events, coastal communities have continued to develop in recent times with new
housing, maritime facilities, and resort developments. As a result, more people and
facilities are threatened by the destructive force of tsunamis.
510 Floodplain Management Planning
Communities are encouraged to prepare and adopt tsunami hazard management plans
that guide land use development, redevelopment, post-disaster recovery, and mitigation
decisions. Credit for preparing, adopting, implementing, evaluating, and updating such
a plan could be credited under Activity 510 (Floodplain Management Planning).
Section 511.a(4) of the CRS Coordinator’s Manual provides extra points for a
discussion of all special hazards that affect the community and for including a summary
of the impact of each hazard on the community and its economy and tax base.
520 Acquisition and Relocation
If there are structures in areas of tsunami hazards that pose a danger to the occupants,
or are repetitively damaged by tsunami flooding, acquisition and relocation may be the
most cost-effective way of solving the problem. Although there is no extra credit for
acquisition and relocation of properties in areas of tsunami hazard, the credit offered in
Activity 520 is substantial.
Credit is only provided for buildings within the regulatory floodplain that is managed
by the community, so the mapping of areas with tsunami hazards in Activity 410TS
may be important for this credit.
Under current policy, if a flood damages an insured building and the state or
community declares the building to be substantially damaged, an NFIP flood insurance
policy claim may provide assistance to help pay to relocate the structure, up to a
maximum benefit of $30,000. This is in addition to coverage for the repair of physical
damage from flooding. When properties are acquired and relocated using these funds
and the vacant property is preserved as open space, CRS credit is available to the
community.
530 Flood Protection
Elevating Buildings
Elevated buildings in subduction zones (West Coast, Alaska, and Puerto Rico) become
soft story structures when elevated and then are even more vulnerable to severe ground
shaking that occurs during the subduction zone earthquake prior to the tsunami wave it
generates. However, in non-subduction zones, elevation should work but only if
engineered for the force of tsunami currents and scour.
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Structural Flood Control
It should be noted that the CRS does not provide credit for structural flood control
projects that can result in a revision to the FIRM. Similarly, the CRS does not provide
credit for coastal structural projects that may be installed to affect erosion rates,
including seawalls, groins, and beach nourishment.
600 Flood Preparedness Activities
610 Flood Warning Program
TsunamiReady is a National Weather Service (NWS) initiative that promotes the
development of community tsunami warning system capability for immediate response.
The program supports better and more consistent tsunami awareness as its main goal is
improvement of public safety during tsunami emergencies.
CRS TsunamiReady credit is described under Section 611.e of the Coordinator’s
Manual. To receive TsunamiReady credit communities must:
(1) Meet the mapping requirements for special hazard credit, as described in Sections
410TS and 430TS, and
(2) Have adopted a tsunami hazard operations plan or annex that addresses actions to
take following a tsunami warning. This would be a document that covers steps
similar to the emergency warning dissemination (EWD) and other response efforts
(ORE) credited in Sections 611.b and c.
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REFERENCES
California Division of Mines and Geology. 1995. Planning Scenario in Humboldt and
Del Norte Counties, California, for a Great Earthquake on the Cascadia Subduction
Zone. Special Publication 115. Sacramento, CA: California Department of
Conservation.
California Office of Emergency Services. n.d. “Local Planning Guidance on Tsunami
Response,” 2nd edition. Sacramento, CA: OES.
Dillon, William P. et al.. 1987. “Geology of the Caribbean,” Oceanus 30 (4): 42-52.
Oregon Geology. 1992. “Field Trip Guide: Natural Hazards of the Pacific Northwest
(Shoreline Submergence at Netarts Bay),” Oregon Geology 54(4): 84
Florida Institute of Technology. no date. “Caribbean Tsunami Awareness”, University
Publications EN-158-399. Melbourne, FL: FIT. 4 pp.
Heaton, Thomas, H. 1992. “Seismic Threat to the Pacific Northwest,” EQE Review
(Fall): 13-18.
Lockridge, Patricia A., Lowell S. Whiteside, and James F. Lander. 2002. “Tsunamis
and Tsunami-like Waves of the Eastern United States.” Science of Tsunami Hazards
20(3): 120-157.
National Oceanic and Atmospheric Administration. 1993. Tsunamis Affecting the West
Coast of the United States: 1806-1992. NGDC Documentation N.29. Washington, D.C.:
U.S. Department of Commerce.
National Oceanic and Atmospheric Administration. 1989. United States Tsunamis:
1690-1988. Publication No. 41-2. Washington, D.C.: U.S. Department of Commerce.
National Oceanic and Atmospheric Administration. 1999. 1997-1999 Activities of the
Tsunami Hazard Mitigation Subcommittee. National Tsunami Hazard Mitigation
Program. Washington, D.C.: U.S. Department of Commerce.
Organization of American States. 1991. Primer on Natural Hazard Management in
Integrated Regional Development Planning. Washington, D.C.: U.S. Agency for
International Development. Available at
http://www.oas.org/dsd/publications/unit/oea66e/begin.htm#Contents
National Tsunami Hazard Mitigation Program. 2001. Designing for Tsunamis.
Washington, D.C.: U.S. Department of Commerce. Available at
http://mitigation.eeri.org/view_object.php?id=121.
Mitigation of Tsunami Hazards
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Oregon Department of Geology and Mineral Industries 2000. Program Summary and
Abstracts of the Penrose Conference 2000: Great Cascadia Earthquake Tricentennial.
Special Paper 33. Portland, OR: DOGAMI.
Oregon Emergency Management and Oregon Department of Geology and Mineral
Industries. 2000. “Tsunami Warning Systems and Procedures” Guidance for Local
Officials.” Salem, OR: Oregon Emergency Management Department. 58 pp.
Priest, George R. 1995. Tsunami Hazard Map of the Depoe Bay Quadrangle, Lincoln
County, Oregon. Open File Report O-95-27. Portland, OR: Oregon Department of
Geology and Mineral Industries.
Satake, Kengi, et al. 1996. “Time and Size of a Giant Earthquake in Cascadia Inferred
from Japanese Tsunami Records of January, 1700.” Nature 379 (January 18): 246-248.
U.S. Geological Survey. 1999. Surviving a Tsunami—Lessons from Chile, Hawaii, and
Japan. Circular 1187. Reston. VA: U.S. Geological Survey.
Uri ten Brink, Uri, William Dillon, Arthur Frankel, Charles Mueller ,and Rafael W.
Rodriguez, editors. 1999. Seismic and Tsunami Hazards in Puerto Rico and the Virgin
Islands. Report of a Workshop held at Colegio de Ingenieros y Agrimensores, San Juan,
Puerto Rico. U.S. Geological Survey Open File report 99-353. Reston, VA: USGS.
Available at http://pubs.usgs.gov/of/1999/of99-353/index.html.
Wallace, Terry C. 2000. “The Hazards from Tsunamis.” TsuInfo Alert 2 (2): 5.
Available from http://www.dnr.wa.gov/geology/tsuinfo/2000-02.pdf.
Williams, Bob (staff writer) 2000. “A New Wave of Concern in NC.” The News and
Observer (Raleigh, North Carolina), May 4, p.1.
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GLOSSARY
Bathymetry—Depth measurement in a body of water
Critical facilities:
─ Structures or facilities that produce, use, or store highly volatile, flammable,
explosive, toxic and/or water-reactive materials;
─ Hospitals, nursing homes, and housing likely to contain occupants who may not
be sufficiently mobile to avoid death or injury during a flood;
─ Police stations, fire stations, vehicle and equipment storage facilities, and
emergency operations centers that are needed for flood response activities
before, during, and after a flood; and
─ Public and private utility facilities that are vital to maintaining or restoring
normal services to flooded areas before, during, and after a flood.
Epicenter—The point on the earth’s surface directly above the focus of an earthquake.
Hazard disclosure—A state or local requirement or practice whereby realtors and/or sellers
reveal known hazards associated with the property in question.
Inundation (map)—The area inundated by a tsunami.
Mitigation—A sustained action taken to reduce or eliminate the long-term risk to human life
and property.
Recurrence interval—The time in years when an event will, on the average, be equaled or
exceeded. For example, a 100-year flood will be equaled or exceeded, on the average, one
every 100 years. It is the inverse of the annual exceedance probability. That is, the 100-year
flood has an annual probability of being exceeded of 1/100, or 0.01.
Risk—Refers to potential losses associated with a hazard, defined in terms of expected
probability and frequency, exposure and consequences. Associated terms include riskreduction, risk assessment, risk analysis and acceptable risks.
Run-up—In this report, run-up refers to the maximum inland extent or elevation attained by a
tsunami. There are other technical definitions. Run-up is also defined as the height of a
tsunami above a general reference level (e.g., height of tide, mean low water, or sea level, if
the tide level at the time of maximum wave was not observed).
Seiche—Oscillations in confined bodies of water (e.g., lakes, bays) caused by earthquakes,
landslides, or high winds. Water moving back and forth from one side of a swimming pool or
bathtub to another are often used as an analogy.
Subduction—The movement of one of the earth’s plates beneath another plate.
Tele-tsunami—Tsunamis observed at places at least 1000 km from their source.
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Tsunami Mitigation Subcommittee—A multi-state subcommittee of the National Tsunami
Hazard Mitigation Program. Representatives from Alaska, California, Hawaii, Oregon,
Washington, and the Federal Emergency Management Agency meet on a scheduled basis to
discuss progress in tsunami hazard mitigation within the respective states.
TsunamiReady program—A National Oceanic and Atmospheric Administration program
patterned after the StormReady program. The program encourages tsunami-susceptible
communities to adopt risk reduction activities.
Mitigation of Tsunami Hazards
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Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
National Flood Insurance Program
Community Rating System
CRS Credit for Mitigation of
Tsunami Hazards
ACTIVITY
WORKSHEETS
2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
INSTRUCTIONS
The following activity worksheets are to facilitate calculations of Community Rating
System (CRS) credit points. They are not used for a community’s initial application to
the CRS. INITIAL APPLICATIONS FOR THE CRS ARE SUBMITTED USING THE WORKSHEET
PAGES IN THE CRS A PPLICATION .
These activity worksheets are for internal use by the community, for submittal of
modifications, and for use by the ISO/CRS Specialist during verification and cycle
verification of a community’s program.
These worksheets are designed to be used in conjunction with CRS Credit for
Mitigation of Tsunami Hazards. Each section of the worksheets corresponds to a
section in that supplement. If a section is missing from the worksheets, it is because the
CRS Credit for Mitigation of Tsunami Hazards supplement shows that no data or
calculations are required for that section.
It is recommended that these worksheets be photocopied before they are used.
When used for submitting a modification, the Credit Points, Credit Calculation, and
Credit Documentation parts of the worksheets should be completed for each activity for
which credit is requested. Fill in the blanks with the value for each variable.
Each worksheet has a Credit Documentation section. Check the blanks to denote that all
of the required documentation is available. In some cases, the documentation must be
provided with the modification. In others, checking the appropriate spaces confirms
that you will provide the documentation when needed. Please consult CRS Credit for
Mitigation of Tsunami Hazards if you have questions about which documentation is to
be provided with the request for a modification.
ATTACH THE REQUIRED DOCUMENTATION FOR AN ACTIVITY TO THE WORKSHEET FOR THAT
ACTIVITY . If the documentation is ordinance language, attach only the necessary page(s)
from the ordinance.
M ARK THE MARGINS OF THE DOCUMENTATION WITH THE ACRONYM for the element so the
ISO/CRS Specialist can identify the basis for the credit.
Mitigation of Tsunami Hazards
AW-TS-iii
Edition: 2006
[This page intentionally blank.]
Mitigation of Tsunami Hazards
AW-TS-iv
Edition: 2006
OMB No.1660-0022
Expires June 30, 2007
Community : ____________________________
410TS ADDITIONAL FLOOD DATA
411TS Credit Points
a. Prerequisites:
____ 1. The area mapped is subject to regulations designed to minimize future
exposure to tsunami damage.
____ 2. The FEMA Regional Office has approved the mapping study.
b.
Tsunami Hazards: (MTS = one of the following methods):
1. Mapping tsunami areas outside the SFHA (50 points)
_______
2. Where mapped areas in the SFHA have regulatory elevations
higher than the base flood elevations on the FIRM (50 points)
_______
3. Where mapped areas in the SFHA have regulatory elevations
lower than the base flood elevations on the FIRM (25 points)
_______
MTS = c410TS = __________
Add this credit to the value for AFDSH under Section 413 on page AW-410-2.
414TS Credit Documentation
a. A map that shows areas subject to tsunami hazards and other floodplains
(including the SFHA) in the community.
b. A description of the method used for mapping the tsunami hazard and documentation that the method is acceptable to the FEMA Regional Office.
c. Documentation that shows the community receives at least 20 points under
Section 421TS and/or Section 431TS.
Comments: _______________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
___________________________________________________________________________
Mitigation of Tsunami Hazards
AW-TS-1
Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
OMB No.1660-0022
Expires June 30, 2007
Community : ____________________________
420TS OPEN SPACE PRESERVATION
421TS Credit Points
a. Prerequisites:
___ 1. The area must meet the credit criteria for open space preservation
in Activity 420.
___ 2. The area must be included in the tsunami hazard area credited
under Activity 410TS.
b. TSOS = ___________
422TS Impact Adjustment
a. Option 1: rTSOS = 1.0.
=
________
b. Option 2: rTSOS = 0.2.
=
________
c. Option 3: rTSOS = aTSOS =
aTS
________
423TS Credit Calculation
c420TS =
TSOS _______ x rTSOS ______ =
c420TS =
_______
Add this credit to the value for cSHOS on line 423d, AW-420-1.
424TS Credit Documentation
_____ a. Documentation that the community receives credit under 410TS.
_____ b. Documentation that shows that the area meets the preservation requirements for
Activity 420 (Open Space Preservation in the CRS Coordinator’s Manual).
Comments: ________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Mitigation of Tsunami Hazards
AW-TS-2
Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
OMB No.1660-0022
Expires June 30, 2007
Community : ____________________________
430TS HIGHER REGULATORY STANDARDS
431TS Credit Points
a. Prerequisites:
____
The regulations are based on the tsunami mapping credited in Section 411TS.
b. Tsunami Regulations (TSR) Total of the following points (not to exceed 70 points).
1. Buildings must be built at or above the tsunami elevation that is
higher than the base flood elevation on the FIRM (40 points)
= ________
2. New critical facilities are prohibited in tsunami hazard areas
unless mitigated and there are emergency response measures
(15 points)
= ________
3. The community has adopted the tsunami construction
requirements in the Coastal Construction Manual (30 points)
= ________
4. New buildings in the tsunami hazard area must be inspected
by a qualified engineer (15 points)
= ________
5. Substantially improved buildings and additions must meet
tsunami construction codes (15 points)
= ________
6. Hazardous materials are prohibited from the tsunami hazard
area (15 points)
= ________
TSR = total of above: (not to exceed 70 points)
TSR = ___________
432TS Impact Adjustment
1. a. Option 1: rTSR = 1.0
=
________
=
________
b. Option 2: rTSR = 0.25
=
________
c. Option 3: rTSR =
=
________
rTSR = 1.0 – rOS.
Mitigation of Tsunami Hazards
aTSR
aTS
AW-TS-3
Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
OMB No.1660-0022
Expires June 30, 2007
Community : ____________________________
433TS Credit Calculation
c430TS = (TSR
x rTSR
c430LZTS (from AW-TS-5)
)
c430TS =
_________
c430LZTS = _________
cSH = total of above
cSH =
_________
Add this credit to the value for cSH on line 433k, page AW-430-2.
434TS Credit Documentation
a. The ordinance(s) or law language that adopts the regulatory standard(s).
b. [If using Option 3] An Impact Adjustment Map showing the regulated tsunami
hazard area.
c. An explanation of the procedures followed for enforcement of the regulatory
standard.
Comments: ________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
___________________________________________________________________
Mitigation of Tsunami Hazards
AW-TS-4
Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
OMB No.1660-0022
Expires June 30, 2007
Community : ____________________________
430LZTS LOW DENSITY ZONING
431LZTS Credit Points
LZTS__ = 5 x __ = 5 x _______
LZTS __ = _______
LZTS__ = 5 x __ = 5 x _______
LZTS __ = _______
LZTS__ = 5 x __ = 5 x _______
LZTS __ = _______
432LZTS Impact Adjustment
2. a.
Option 1: rLZTS = 1.0
=
________
=
________
=
________
c. Option 3: rLZTS__ = aLZTS
aTS
=
________
rLZTS__ = aLZTS
aTS
=
________
rLZTS__ = aLZTS
aTS
=
________
rLZTS = 1.0 – rOS.
b.
Option 2: rLZTS = 0.2
433LZTS Credit Calculation
cLZTS__ = LZTS__ ___ x rLZTS__ ___
=
________
cLZTS__ = LZTS__ ___ x rLZTS__ ___
=
________
cLZTS__ = LZTS__ ___ x rLZTS__ ___
=
________
c430LZTS =
________
c430LZTS = total of above
Add this to the value of c430LZTS on page AW-TS-4
434LZTS Credit Documentation
a. The ordinance(s) or law language that adopts the zoning standard(s).
b. An Impact Adjustment Map showing the regulated tsunami hazard area.
c. An explanation of the procedures followed for enforcement of the regulatory standard.
Comments: ________________________________________________________
___________________________________________________________________
Mitigation of Tsunami Hazards
AW-TS-5
Edition: 2006
OMB No. 1660-0022
Expires: June 30, 2007
Public reporting burden for this information collection is estimated at 35 hours for the application and
certification process. Burden means the time, effort, and financial resources expended by persons to
generate, maintain, retain, disclose, or to provide information to us. You may send comments regarding the
burden estimate or any aspect of the collection, including suggestions for reducing the burden to:
Information Collections Management, U.S. Department of Homeland Security, Emergency Preparedness
and Response Directorate, Federal Emergency Management Agency, 500 C St., S.W., Washington, D.C.
20472, Paperwork Reduction Project (OMB Control Number 1660-0022). You are not required to respond to
this collection of information unless a valid OMB control number is displayed in the upper right corner of this
form. Note: do not send your completed questionnaire to this address.
Activity Worksheet No.
Title
AW-210
AW-214
AW-230
CRS Application Cover Page
Recertification Worksheet
Modification/Cycle Cover Page
AW-310
AW-320
AW-330
AW-340
AW-350
AW-360
Elevation Certificates
Map Information Service
Outreach Projects
Hazard Disclosure
Flood Protection Information
Flood Protection Assistance
AW-410
AW-420
AW-430
AW-430LD
AW-440
AW-450
Additional Flood Data
Open Space Preservation
Higher Regulatory Standards
Land Development Criteria
Flood Data Maintenance
Stormwater Management
AW-501
AW-502
AW-510
AW-520
AW-530
AW-540
Repetitive Loss List
Repetitive Loss Requirements
Floodplain Management Planning
Acquisition and Relocation
Flood Protection
Drainage System Maintenance
AW-610
AW-620
AW-630
Flood Warning Program
Levee Safety
Dam Safety
AW-710
AW-720
AW-720m
Community Growth Adjustment
Community Credit Calculations
Community Credit Calculations (Modification)
AW-CB
AW-CE
AW-DB
AW-IJ
AW-MF
AW-SU
AW-TS
AW-UF
Closed Basin Lake Hazards
Coastal Erosion Hazards
Dunes and Beaches
Ice Jam Hazards
Mudflow Hazards
Land Subsidence Hazards
Tsunami Hazards
Uncertain Flow Path Hazards
| File Type | application/pdf |
| File Title | Microsoft Word - AA Tsunami Supplement 2006 final.doc |
| Author | Owner |
| File Modified | 2009-01-09 |
| File Created | 2009-01-09 |