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IF YOU FEEL AN EARTHQUAKE WHEN YOU ARE ON THE OREGON COAST, PROTECT YOURSELF FROM THE EARTHQUAKE UNTIL IT IS OVER.

THEN MOVE QUICKLY INLAND OR TO HIGH GROUND.

A TSUNAMI MAY BE COMING IN A FEW MINUTES, AND ADDITIONAL LARGE WAVES MAY CONTINUE FOR SEVERAL HOURS.

THE INFORMATION IN THIS BROCHURE MAY SAVE YOUR LIFE. PLEASE TAKE THE TIME TO READ IT AND SHARE WHAT YOU HAVE LEARNED WITH YOUR FAMILY AND FRIENDS.

TSUNAMI FACTS

Two kinds of tsunamis could affect the Oregon coast:

 

1. Tsunamis generated by undersea earthquakes just off the Oregon coast can strike the coast within five to thirty minutes, possibly disrupting power lines and communications and leaving little time for an official warning. The actual ground shaking of the earthquake may be the only warning you receive.
2. Tsunamis generated by earthquakes occurring thousands of miles away will take several hours to reach the coast. There would be time for official warning, but if you are in an isolated area, you may not hear the official warning, you will feel no earthquake, and the only warning you may have is a sudden unexpected change in sea level. If the sea level suddenly drops or rises without any obvious reason, nature may be warning you of impending danger, and you should move inland or to high ground immediately.

Recent research shows that at any time the Pacific Northwest can experience large earthquakes and accompanying tsunamis, and that tsunamis have affected the Oregon coast on a regular basis over time. Scientists have not yet had time to do local studies that will be able to tell you how high a tsunami may be in any one area and how far you must run inland or how high you must climb to escape. The best general advice available today is to (1) go up to 2 miles inland if you are in a low-lying area or at least 100 feet above sea level if you can; and (2) go on foot if at all possible because of traffic jams and earthquake damage.

A tsunami wave increases in height as it approaches shore. Typical wave heights from tsunamis occurring in the Pacific over the last 80 years have been between 21 to 45 feet at the shoreline. A few waves, however, have been much higher- as much as 100 feet or more because of local conditions. Also, tsunamis may affect local areas differently, causing great damage and loss of life in one area but little in another.

The Alaskan Good Friday, March 27, 1964, earthquake had a moment magnitude of 9.2. The death toll in Alaska from this event was 115 people, with 106 of the deaths due to tsunamis.

A tsunami generated by the same 1964 Alaska earthquake also struck the Oregon coastline, killing four people and causing nearly $1 million damage (in 1964 dollars). The highest officially measured tsunami wave was 14.2 feet at the mouth of the Umpqua River. When the same tsunami struck Crescent City, California, the maximum wave height was 14 feet, 11 people were killed, and approximately $8 million of damage was done. Heights of tsunami waves generated by nearby earthquakes could be much higher.

In 1960, a Chilean moment-magnitude-9.5 earthquake produced tsunamis that struck the relatively sparsely populated coast of Chile, killing nearly 1,000 people and leaving tsunami deposits similar to those found along the Oregon coast.

On July 12, 1993, a moment-magnitude-7.8 earthquake generated tsunami waves ranging from 10 to 100 feet high at Okushiri Island, Japan. About 200 people were killed, most of them by the tsunamis. More would have been killed, but many people still remembered or had heard of earlier tsunamis and went immediately inland and to high ground to safety after the shaking stopped.

WHAT IS A TSUNAMI (SOO-NAHMEE)?

A tsunami is a series of sea waves usually caused by displacement of the ocean floor by an undersea earthquake. The waves travel at speeds up to 600 miles per hour, sometimes crossing the entire Pacific Ocean. As tsunamis enter shallow water near land, they increase in height and can cause great loss of life and property damage where they come ashore. Remember, a tsunami is not one wave but a series of waves. People have died when they assumed they were safe because they had survived one large wave, only to be caught by a later arriving, larger wave.

WHEN DOES A TSUNAMI OCCUR?

It can occur any time of day or night after an undersea earthquake. Experts believe that a tsunami caused by an undersea earthquake near the Oregon coast could strike the Oregon coast within 5-30 minutes after the earthquake, before official warning is possible. Undersea earthquakes thousands of miles away can cause smaller tsunamis on the Oregon coast but will take several hours to arrive, generally allowing time for official warning.

WHERE DO TSUNAMIS OCCUR?

Tsunamis are most common in the Pacific Ocean. People on open beaches, at low-lying areas of the beach, by bay mouths or bay tidal flats, in low parts of coastal towns and cities, and near mouths of rivers draining into the ocean are in greatest danger from tsunamis.

WHAT AGENCIES GIVE OFFICIAL TSUNAMI WARNINGS?

The Alaska Tsunami Warning Center gives warnings for tsunamis generated by earthquakes off the West Coast of the United States and Canada. The Pacific Tsunami Warning Center gives warnings for tsunamis generated around the rest of the Pacific.

Alaska Tsunami Warning Center
910 S. Felton Street
Palmer, AK 99645
Phone (907) 745-4212

Pacific Tsunami Warning Center
91-270 Fort Weaver Road
Ewa Beach, HI 96706-2928
Phone (808) 689-8207

HOW CAN I SAVE MYSELF FROM A TSUNAMI?

1. If you feel an earthquake when you are along the coast, protect yourself from the effects of the earthquake by dropping, covering, and holding on if you are inside and staying away from falling objects if you are outside until the earthquake is over.

2. Then, even though you may have been frightened or hurt by the earthquake, you must immediately move inland or to high ground, away from low-lying areas that could be affected by tsunamis. Tsunamis can travel upstream in coastal estuaries and rivers, with damaging waves extending farther inland than the immediate coast. Evacuate on foot if possible because of traffic jams and probable earthquake damage to roads and bridges. If you are unable to reach safe ground, the third floor or higher of a reinforced concrete building may offer protection, but such a building should be used only as a last resort. Do not wait for an official warning because the tsunami may strike before authorities have time to issue a warning.
3. If you think you have time, get your disaster supply kit (see "What Can I Do Ahead of Time").
4. Do not return to the shore after the first wave. Additional waves may arrive later, be higher, and go farther inland. Waves may continue to come in for several hours. Wait until officials tell you the tsunami danger has passed.
5. If you are camping on or near the beach, you may have to immediately abandon your recreation vehicle or campsite to go inland or to higher ground to save your life.
6. Never go to the beach to watch for a tsunami. Tsunamis move faster than a person can run. Also, incoming traffic hampers safe and timely evacuation of coastal areas.
7. If you see a sudden and unexpected rise or fall in coastal water, a tsunami may be approaching. Do not wait to investigate, because the next wave may be a large tsunami. Instead move inland or uphill as quickly as possible.
8. Stay tuned to your radio, marine radio, NOAA weather radio, or television station during a tsunami emergency. Bulletins issued through your local emergency management and National Weather Service offices can save your life.

WHAT CAN I DO AHEAD OF TIME TO PROTECT MYSELF FROM A TSUNAMI?

1. Make disaster plans before a disaster occurs. Family members should be trained so that they know what to do on their own to protect themselves from an earthquake, where to go to survive a tsunami, and whom out of the disaster area to contact in case they are separated from each other by a disaster.
2. Assemble a disaster supply kit containing such items as a battery-operated radio, flashlight, extra batteries, water, extra prescription drugs, a blanket, and a change of clothes that can be picked up if there is time as you move away from tsunami danger. Keep the kit in an easily accessible place.
3. Contact local emergency officials to find out which areas are most vulnerable to tsunami hazard, which areas are safest, and which routes are best for evacuation.
4. Take a first aid course, and learn other survival skills. Knowledge of how to save yourself is your greatest defense against any potential disaster.
5. Remember, coastlines anywhere are vulnerable to tsunamis, but tsunamis are infrequent. Understand the hazard and learn how to protect yourself, but don't let the threat of tsunamis ruin your enjoyment of the beach.

International Tsunami Information Center
Box 50027
Honolulu, HI 96850-4993
Phone (808) 541-1658

INFORMATION ON OREGON EARTHQUAKES AND TSUNAMIS:

Oregon Dept. of Geology and Mineral Industries
800 NE Oregon St. #28 - Suite 965
Portland, OR 97232
Phone (503) 731-4100

PUBLICATIONS AND BROCHURE$ ON EARTHQUAKES,
TSUNAMIS, AND GEOLOGY:

Nature of Oregon Information Center
800 NE Oregon #5 - Suite 177
Portland, OR 97232
Phone (503) 731-4444
Also (503) 523-3133 in Baker City and
(503) 476-2496 in Grants Pass

INFORMATION ABOUT EMERGENCY PREPAREDNESS:

American Red Cross, Oregon Trail Chapter
Emergency Services, PO Box 3200
3131 N. Vancouver Ave.
Portland, OR 97208-3200
Phone (503) 284-1234, ext. 238

Department of State Police
Oregon Emergency Management
595 Cottage St. NE
Salem, OR 97310
Phone (503) 378-2911

COASTAL COUNTY EMERGENCY OFFICES
FOR LOCAL EMERGENCY INFORMATION:

Clatsop County Sheriff's Office,
Emergency Services Division
PO Box 658 - Astoria, OR 97103
Phone (503) 325-8635

Coos County Emergency Services
County Courthouse - Coquille, OR 97423
Phone (503) 396-3121 ext. 398

Curry County Emergency Services
PO Box 746 - Gold Beach, OR 97444
Phone (503) 247-7011

Douglas County Emergency Services
Justice Building - Roseburg, OR 97470
Phone (503) 440-4448

Lane County Emergency Services
Courthouse, 125 East 8th Ave. - Eugene, OR 97401
Phone (503) 687-4160
Emergency/24 hour (503) 687-3978

Lincoln County Emergency Services
Courthouse, Room 103
225 W. Olive St. - Newport, OR 97365
Phone (503) 265-4199

Tillamook County Emergency Management
Courthouse, 201 Laurel Ave. - Tillamook, OR 97141
Phone (503) 842-3412

Federal Emergency Management Agency, Region X
130 228th Street SW - Bothell, WA 98021-9796
Phone (206) 487-4600

4.  Listen to your radio for an
official "all clear" before returning
to the beach.

(Original brochure) Printed courtesy of Portland General Electric Company. Funded in part by the Oregon State Lottery. Prepared by the Oregon Department of Geology and Mineral Industries in partnership with the Extension Sea Grant Program at Oregon State University and the Federal Emergency Management Agency, Region X, with help from the National Oceanic and Atmospheric Administration.

The web version of this publication was created by David Gronbeck-Jones, British Columbia Provincial Emergency Program, on behalf of the State of Oregon and the Western States Seismic Policy Council (WSSPC).

URL: ... /Ore_wave.html
Updated: July 14, 2000