Department of Emergency Management

TSUNAMI GENERAL INFORMATION

WHAT	TRANSPORTATION
WHERE	ROADBLOCKS
TIMING	ALL CLEAR
ALERTING	PROHIBITIONS
EVACUATION INSTRUCTIONS	RUMORS
SCHOOLS	FLOOD INSURANCE
SIRENS	EMERGENCY ASSISTANCE

 WHAT

A tsunami can be one or a series of ocean waves caused by violent movement of the earth's crust (generally earthquakes) below or near the ocean floor. Once generated, the waves move outward from the earthquake epicenter at speeds varying with the water depth. In the deep ocean the speed can exceed 450 MPH, traversing the entire Pacific Ocean in about 25 hours. Once the waves impact a coastal area, water level fluctuations and unusual current conditions may continue for up to 24 hours or more.

 WHERE

Because surrounding shallow areas cause the waves to bend as they pass an island, all the coastal areas of Oahu are vulnerable to tsunami flooding as the waves "wrap around" the island. In other words, the severity of flooding (wave height) in any coastal area around our island cannot be accurately predicted based solely on the location of the generating earthquake. See the Tsunami Evacuation Maps for areas that must be evacuated. 

TIMING

The speed at which tsunamis move can be reliably predicted. Depending on the earthquake source area, travel times can range from a few minutes for tsunamis generated within or close to the Hawaiian Islands to about 4 hours for those originating in the Alaska/Aleutian area, and as much as 12 to 15 hours for tsunamis generated in South America. For locally generated tsunamis, immediate action is required.

  As a general rule, tsunamis with travel times of 6 hours or less also require immediate action. For tsunamis with travel times of greater than 6 hours, immediate action may not be required, however, a steady, consistent evacuation process must be initiated and maintained.

 Listen for Department of Emergency Management instructions over radio and television stations for all evacuation guidance.

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 ALERTING

Department of Emergency Management (DEM) issues alerts and advisories to the public based on bulletins and phone calls received directly from the Pacific Tsunami Warning Center (PTWC). PTWC also provides this same information to the local news media.

TSUNAMI WATCH - Announced by PTWC when the magnitude and source area of an earthquake are considered significant but the Center is unable to verify that a tsunami has been generated. A TSUNAMI WATCH means prepare. See the sample Tsunami Watch Checklist for planning guidance.

TSUNAMI WARNING - Announced by PTWC when tsunami waves have been confirmed and a threat to life and property exists. A TSUNAMI WARNING means immediate action in coastal areas is required, destructive tsunami waves have been confirmed.   At this time Tsunami Refuge Centers may be opened. 

URGENT TSUNAMI WARNING - Announced by PTWC when a significant earthquake occurs within or close to the Hawaiian Islands. Urgent vertical or horizontal evacuation of evacuation zones is required.  If an URGENT TSUNAMI WARNING is issued IMMEDIATELY leave all coastal evacuatio zones.

TSUNAMI WARNING INSTRUCTONS 

The following guidelines should assure an orderly evacuation of tsunami evacuation zones and keep roadways open for evacuees and emergency vehicles:

When a tsunami warning is issued and/or evacuation is directed by the Department of Emergency Management (DEM):

If located outside a tsunami evacuation zone, stay outside of the evacuation zones. Curtail all non-emergency travel.

If within a tsunami evacuation zone, evacuate beaches and low lying coastal areas IMMEDIATELY. Options include:

Horizontal Evacuation. Walk, if possible, to a safe area or shelter outside the evacuation zones and remain in place.

Vertical Evacuation. Remain in or, if prior arrangements have been made, go to a heavy concrete and steel building of at least six stories. Such structures should provide adequate protection if people move to the third floor or above.

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SCHOOLS

If a TSUNAMI WARNING is issued during normal school hours and wave arrival is 6 hours or less, public and private schools and day care centers located within evacuation zones will evacuate according to their plans. Public schools, and those cooperating private schools and day care centers outside the evacuation zones, will remain open and care for the children under their purview until parents can safely pick them up. Evacuation guidance for wave arrivals exceeding 6 hours will be made by the Department of Emergency Management through radio and television station broadcasts.

Employees with children in public/private schools or day care centers should be aware of school/center tsunami plans.

 SIRENS

Outdoor warning sirens will sound State-wide at 3 hours, 2 hours, 1 hour, and 30 minutes prior to the estimated first wave arrival time. All siren activations will be accompanied by detailed emergency instructions over radio and television stations. If PTWC issues a tsunami warning well in advance of the above siren activation schedule, authorities will use the sirens and the Emergency Alert System (EAS) to warn the public of approaching waves.

 TRANSPORTATION

DEM will announce and the City Public Transit Authority will implement a Tsunami Bus Evacuation Plan in selected coastal areas when a Tsunami Warning is issued. Plan implementation causes City buses to revert from normal routing to an evacuation mode. The busses marked "Special" or "Evacuation", will pick up evacuees at any location on their routes and drop them off near designated Tsunami Refuge Centers. Forty-five (45) minutes prior to estimated first wave arrival, all bus evacuation operations will cease and buses will move to safe areas outside of the tsunami evacuation zones.

 It should be noted that a tsunami evacuation is likely to cause some disruption to all City bus schedules.

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 ROADBLOCKS

To ensure evacuation zones are cleared, the Honolulu Police Department will establish roadblocks to control traffic as soon as practicable. Forty-five (45) minutes prior to estimated first wave arrival, roads will be sealed off and no one will be allowed to enter the evacuation zones.

 Police sweeps of roadways between the roadblocks will require motorists to immediately move to safe locations which may not necessarily be their chosen destinations.

 ALL CLEAR

This condition is announced by DEM over the Emergency Alert System following the cancellation of a Tsunami Warning by the PTWC. The PTWC cancellation signifies that damaging waves are no longer a threat to Oahu. The DEM "All Clear" announcement will be made by the Mayor following initial surveys of tsunami evacuation zones by City public safety forces and specify those zones which are considered reasonably safe for residents to return to. The DEM "All Clear" does not pertain to ports, harbors, channels, and bays around the island where strong residual currents may make entry hazardous. The State Department of Transportation's Harbor Master will make "All Clear" determinations and announcements over marine radio frequencies for those areas.

 PROHIBITIONS

If there is signifigant tsunami damage access to coastal areas may not be possible.  If this occurs emergency shelters wll be opened for those who cannot go home or have no home to go to.   See our current Oahu Hurricane Emergency Shelter List for locations of emergency shelters that may be opened.  Shelter locations and opening times will be broadcast over TV and radio.  Do NOT automatically go to a shelter.

 RUMORS

Do not react, respond to, or assist in spreading rumors concerning current or future storm conditions or other situations caused by the emergency. Take action only in response to information received through official sources.

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 FLOOD INSURANCE

Tsunami inundation is considered a flooding event by insurers. No standard home or building insurance policies contain flooding coverage. Vehicle flooding is covered by comprehensive automobile insurance. National Flood Insurance for buildings and their contents can be purchased through local companies but must be procured prior to a flooding event.

 EMERGENCY ASSISTANCE

Call 911 or the Department of Emergency Management at 723-8960. Hearing impaired who have a TTY may call 527-5467. Disabled or elderly needing assistance in an emergency should call 911. Non-English speaking persons may contact the Pacific Gateway Center at 808-851-7010 for translation service.

 

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