Tsunami Safety and Preparedness: What Guam Residents and Businesses Need to Know

A recent magnitude 8.8 earthquake off Russia's coast sent a tsunami across the Pacific, impacting coastal areas, including Guam. As the waves passed the island, the water rise was measured at approximately six inches. While this may seem minor, the event underscores the necessity of preparedness and highlights a critical safety issue: the widespread, dangerous myth that Guam is naturally protected from tsunamis.

Debunking the Myth: Guam is Not Immune

A common but potentially deadly misconception is that the Mariana Trench and the island's coastal reef system are enough to prevent significant tsunami waves from ever reaching Guam's shores. This is a myth that can lead to complacency and put lives at risk.

While most tsunamis hitting Guam may not generate the massive, towering waves often depicted in movies, they can still cause catastrophic damage. The danger is not a high-breaking wave, but a rapid, forceful surge and recession of water that can overcome barriers and sweep people and vehicles away.

One local account illustrates this threat vividly: A witness noticed the water recede about 15 yards beyond the normal waterline before a rapid surge. A second wave, rising as high as a vehicle's windshield, swept the man and his truck about 30 feet from the shore. This demonstrates that even a relatively small rise in water can be extremely powerful and destructive.

The National Oceanic and Atmospheric Administration (NOAA) has assessed Guam and identified several areas as being particularly susceptible to tsunami effects, including:

• Tumon Bay

• Agana Bay

• Pago Bay

• Apra Harbor

• Inarajan Bay

Tsunami Safety: A Guide to Individual Action

If you are near the ocean and an earthquake occurs, or if you receive an official warning, immediate action is essential. Do not wait for official notification to evacuate if you feel strong, prolonged ground shaking.

Recognizing the Danger	Immediate Steps to Take
Ground Shaking: Strong or long-duration shaking signals a potential tsunami.	Evacuate Immediately: Leave low-lying areas. Go to high ground, at least 100 feet above sea level, and move inland.
Visual/Audible Signs: A loud roar from the ocean, a sudden rise or fall of the water, or a large ocean wall moving towards the shore.	Run to High Ground: Do not stop to observe the wave. Get to safety as quickly as possible.
Post-Wave Danger: Tsunamis often arrive in a series of waves that can be minutes or even an hour apart.	Stay Informed: Listen to local radio and other news outlets for official warnings and the "all clear" before returning to the shore.

Business Preparedness: Planning for Indirect Impact

If your business is located inland and not in a designated low-lying or high-risk area, you may assume you have nothing to worry about. However, a significant tsunami event can still impact your operations by affecting your staff and the general community response.

Businesses must consider the following factors to ensure safety and maintain resilience:

• Employee Safety and Location: Some employees may live in or have to travel through tsunami-risk areas. As a best practice, businesses should allow affected employees to depart immediately to evacuate themselves and their families to safety.

• Family Obligations: A tsunami threat often leads to the early release of children from schools and daycares. Business policies should acknowledge this need and allow staff the time to account for their children.

• Traffic Congestion: Evacuations will cause severe traffic jams. When allowing employees to depart, ensure adequate time is factored in for heavy congestion and blocked routes, preventing them from being stuck in high-risk zones.

• Operational Contingency: A tsunami will mobilize various organizations (emergency services, government agencies). Consider how this response might affect your staff's ability to commute or how it might strain critical community infrastructure, planning for potential operational disruption.

By preparing for both direct and indirect impacts, businesses can better safeguard their employees and support the overall community response during a tsunami emergency.

Reference: U.S. Tsunami Warning Centers