How to Prepare for Submarine Landslides: A Comprehensive Coastal Safety Guide

Submarine landslides represent one of the most destructive yet least visible coastal hazards facing communities worldwide. Unlike their terrestrial counterparts, these underwater avalanches occur beneath the ocean’s surface, often triggering tsunamis with little to no warning. According to the USGS, submarine landslides have caused billions of dollars in damage to underwater infrastructure and coastal communities over the past century. For coastal residents, understanding how to prepare for submarine landslides is not just prudent—it’s essential for survival.

While these underwater events may seem rare, the National Oceanic and Atmospheric Administration (NOAA) has documented over 100 significant submarine landslides along the U.S. continental shelf alone in the past 50 years. Their triggers range from earthquakes and volcanic activity to sea level changes and human activities like offshore drilling. The devastating 2018 Sulawesi tsunami in Indonesia, which killed over 2,000 people, was partially amplified by an underwater landslide—demonstrating the catastrophic potential of these events.

Understanding Submarine Landslides: Causes and Warning Signs

Submarine landslides occur when underwater sediment becomes unstable and moves rapidly downslope. According to research from the Woods Hole Oceanographic Institution, these events can be triggered by several factors that coastal residents should be aware of. Earthquakes remain the most common trigger, but volcanic activity, gas hydrate destabilization, and even strong storm surges can initiate underwater slope failures. The challenge with submarine landslides is their invisibility—they happen beneath the ocean surface where direct observation is impossible without specialized equipment.

Based on extensive research by coastal geologists, several warning signs may precede a submarine landslide, particularly one large enough to generate a tsunami:

Seismic activity: Recent earthquakes, even small ones, in coastal or offshore areas
Unusual water behavior: Rapid recession of water from shorelines (water pulling away from the coast unexpectedly)
Underwater infrastructure damage: Unexplained damage to submarine cables or offshore structures
Volcanic activity: Recent eruptions or increased activity in nearby underwater volcanoes
Unusual sounds: Low rumbling sounds coming from the ocean

Identifying If You Live in a High-Risk Zone

Not all coastal areas face equal risk from submarine landslides. The U.S. Geological Survey has identified several high-risk zones along American coastlines where underwater slope failures are more common. These include the Atlantic continental margin, parts of Alaska, Hawaii, Puerto Rico, and sections of the Pacific Northwest. Many coastal communities in these regions have developed specific emergency response plans that account for submarine landslide risks.

For homeowners and businesses in coastal areas, understanding your risk level is the first step in preparation. At Batten Home Security, we’ve found that many coastal residents are unaware of their vulnerability to submarine landslide-generated tsunamis until they conduct proper risk assessments of their properties.

How to Determine Your Risk Level:

Consult local hazard maps: Many coastal counties have tsunami and submarine landslide hazard maps available through emergency management offices
Check NOAA resources: The NOAA Tsunami Program provides risk assessment tools for coastal communities
Contact local geological surveys: State geological surveys often maintain detailed records of underwater slope stability
Review historical events: Research whether your area has experienced submarine landslides or tsunamis in the past
Elevation assessment: Properties at lower elevations and closer to shorelines face higher risks

Creating a Submarine Landslide Emergency Plan

For coastal residents in vulnerable areas, having a specialized emergency plan for submarine landslides and their resulting tsunamis is critical. According to emergency management experts at FEMA, families in tsunami hazard zones should have detailed evacuation plans that can be executed within minutes. Unlike hurricanes, which provide days of warning, submarine landslide tsunamis may only offer minutes between the first warning signs and wave arrival.

When working with coastal communities, we’ve found that the most effective emergency plans include clear evacuation routes to higher ground, designated family meeting points, and regular drills to ensure everyone knows exactly what to do when minutes count. The plan should account for various scenarios, including evacuations during different times of day and in various weather conditions.

Key Components of Your Emergency Plan:

Evacuation routes: Identify multiple paths to reach higher ground (at least 100 feet above sea level or 2 miles inland)
Meeting locations: Designate primary and secondary meeting points for family members
Communication protocol: Establish how family members will contact each other if separated
Emergency contacts: Maintain a list of important contacts, including an out-of-area contact person
Evacuation timing: Practice evacuations to know exactly how long it takes to reach safety
Pet considerations: Include plans for evacuating with pets or livestock
Special needs: Account for family members with mobility issues or medical requirements

Essential Emergency Supplies for Coastal Residents

The aftermath of a submarine landslide-generated tsunami can leave coastal communities isolated for days or even weeks. According to the American Red Cross, households in tsunami zones should maintain emergency kits that can sustain all family members for a minimum of two weeks. These kits should be stored in waterproof containers at higher elevations when possible, as home-based supplies may be destroyed in the event of flooding.

Many of the coastal homeowners we work with at Batten maintain two separate emergency kits: a grab-and-go kit stored near home exits for immediate evacuation, and a more comprehensive supply cache stored at their designated safe location. This dual-kit approach ensures that immediate needs are met during evacuation while providing for longer-term requirements during recovery.

Essential Supplies for Your Emergency Kit:

Water: One gallon per person per day for at least two weeks
Non-perishable food: High-calorie, ready-to-eat options that don’t require cooking
Communication tools: Battery or hand-crank powered NOAA weather radio, whistles, signal mirrors
First aid supplies: Comprehensive kit including prescription medications
Lighting: Waterproof flashlights, headlamps, and chemical light sticks
Documents: Waterproof container with copies of important documents (insurance policies, identification, property deeds)
Cash: Small bills and coins as electronic payment systems may be unavailable
Clothing: Complete change of clothing, sturdy shoes, and rain gear
Sanitation supplies: Personal hygiene items, portable toilet, garbage bags
Multi-purpose tools: Utility knife, duct tape, work gloves, basic tools

Our emergency preparation experts recommend these comprehensive emergency kits that contain essentials specifically selected for coastal hazards.

Home Preparation and Structural Considerations

While no residential structure can be made completely tsunami-proof, certain structural modifications can help reduce damage from smaller tsunami waves and improve the chances of home recovery after an event. According to coastal engineers, homes in tsunami-prone areas should be built or modified with flood-resistant materials and elevated foundations when possible. The goal isn’t necessarily to make the home withstand a direct tsunami impact, but rather to minimize damage from smaller waves and storm surge that may accompany submarine landslide events.

Many coastal homeowners we’ve worked with have implemented strategic home modifications that balance tsunami resilience with practical considerations and budget constraints. These modifications focus on protecting critical home systems and reducing potential water damage.

Home Preparation Strategies:

Elevation considerations: When building new, elevate structures above base flood elevation levels
Foundation reinforcement: Consult with structural engineers about options to strengthen existing foundations
Utility protection: Elevate electrical panels, water heaters, and HVAC equipment
Flood-resistant materials: Use marine-grade materials for lower levels of coastal homes
Breakaway walls: For homes on stilts, design lower enclosures to break away during flooding without damaging the main structure
Water barriers: Consider deployable flood barriers for doors and windows (recognizing these are primarily for storm surge, not major tsunamis)
Secure outdoor items: Anchor or store items that could become dangerous projectiles

Understanding Tsunami Warning Systems

The U.S. Tsunami Warning System, operated by NOAA, provides alerts for tsunamis generated by earthquakes but has limitations when it comes to submarine landslide-generated tsunamis. According to NOAA scientists, landslide tsunamis often occur with minimal warning time because they can be triggered by smaller, sometimes undetected seismic events. This makes understanding natural warning signs and having multiple alert methods particularly important for coastal residents.

From our experience working with coastal communities, we’ve found that residents who understand both official warning systems and natural warning signs have the best chance of evacuating safely during sudden-onset events. Many coastal residents install multiple alert systems in their homes to ensure warnings are received regardless of time of day or power status.

Warning Systems and Alert Methods:

NOAA Weather Radio: Battery or hand-crank powered radio that receives official warnings
Wireless Emergency Alerts (WEA): Ensure mobile phones are set to receive government alerts
Emergency Alert System (EAS): Broadcasts on TV and radio
Tsunami sirens: Familiarize yourself with local warning sirens and their patterns
Community alert systems: Many coastal communities have text or phone alert systems
Smart home integration: Modern security systems can be configured to receive and announce emergency alerts
Natural warnings: Recognize that strong ground shaking, unusual ocean behavior, or strange sounds from the ocean may be your only warning

For comprehensive home safety, consider Batten’s recommended security systems that integrate emergency alerts with home monitoring.

Insurance and Financial Preparedness

Financial recovery after a submarine landslide-generated tsunami presents unique challenges. According to insurance experts, standard homeowners insurance typically excludes flood damage, including tsunami damage. FEMA’s National Flood Insurance Program (NFIP) provides coverage for flood events, but policy details and coverage limits require careful review. Many coastal residents are surprised to learn about these coverage gaps after a disaster has already occurred.

Based on our work with coastal homeowners, we’ve found that the most financially prepared families maintain comprehensive documentation of their property and possessions, understand their insurance coverage limitations, and maintain emergency financial reserves. This multi-layered approach to financial preparedness provides the best chance for recovery after a catastrophic event.

Financial Preparedness Steps:

Insurance review: Confirm whether your policy covers tsunami damage (most standard policies don’t)
Flood insurance: Consider purchasing NFIP coverage or private flood insurance
Documentation: Maintain digital and physical records of property deeds, insurance policies, and financial accounts
Home inventory: Create video or photographic documentation of home contents with approximate values
Emergency fund: Maintain accessible emergency savings (experts recommend 3-6 months of expenses)
Important contacts: Keep a list of insurance agents, policy numbers, and claim phone numbers
Secure storage: Store important documents in waterproof containers and maintain digital copies in cloud storage

Community Involvement and Education

Individual preparation, while essential, is most effective when paired with community-wide preparedness efforts. According to emergency management experts, communities with established tsunami preparedness programs experience significantly lower casualty rates during actual events. These programs typically include regular drills, clear evacuation signage, and ongoing public education campaigns.

We’ve observed that coastal communities with the highest levels of preparedness maintain active Community Emergency Response Teams (CERT), conduct regular tsunami evacuation drills, and integrate tsunami education into school curricula. This community-based approach ensures that knowledge and preparation become part of the local culture rather than an individual responsibility.

Community Preparedness Actions:

Join local CERT: Volunteer with Community Emergency Response Teams
Attend drills: Participate in community tsunami evacuation exercises
Know evacuation routes: Familiarize yourself with officially designated evacuation routes
Support education: Advocate for tsunami education in local schools
Neighborhood planning: Work with neighbors to identify vulnerable residents who may need evacuation assistance
Share knowledge: Educate visitors and new residents about tsunami risks and procedures
Business continuity: If you own a coastal business, develop and share your tsunami response plan with employees

Recovery Planning: After a Submarine Landslide Event

Recovery from a submarine landslide-generated tsunami presents unique challenges due to the extensive damage these events can cause to coastal infrastructure. According to FEMA, communities may face prolonged power outages, contaminated water supplies, and limited access to essential services. Planning for these post-disaster challenges is a critical component of comprehensive preparedness.

The most resilient coastal residents we’ve worked with develop detailed recovery plans that address immediate post-disaster needs while also considering longer-term recovery requirements. These plans account for the possibility of extended displacement from homes and prolonged disruption to normal services.

Recovery Planning Considerations:

Temporary housing: Identify inland locations where you could stay for extended periods
Communication plan: Establish how you’ll reconnect with family and notify others of your safety
Return safety: Understand hazards when returning to tsunami-impacted areas (structural damage, contamination)
Insurance claims: Know the process for filing claims and documenting damage
Assistance programs: Familiarize yourself with FEMA and other disaster assistance programs
Mental health resources: Identify counseling services that specialize in disaster recovery
Business continuity: For business owners, develop plans for resuming operations or accessing business interruption assistance

Special Considerations for Vulnerable Populations

Certain populations face heightened vulnerability during submarine landslide-generated tsunamis. According to research from emergency management agencies, the elderly, people with disabilities, families with young children, and visitors unfamiliar with the area face unique challenges during rapid evacuations. Comprehensive preparation must account for these special needs to ensure no one is left behind during an emergency.

Working with coastal communities, we’ve found that the most effective preparedness plans include specific provisions for vulnerable populations, including buddy systems, specialized evacuation equipment, and targeted outreach programs. These inclusive approaches ensure that emergency response serves the entire community.

Considerations for Vulnerable Populations:

Mobility assistance: Identify evacuation chairs or other devices for those with limited mobility
Medical needs: Plan for power-dependent medical equipment and medication storage
Communication barriers: Develop methods to alert those with hearing or vision impairments
Visitor education: If you operate vacation rentals or hotels, provide clear tsunami information to guests
Pet evacuation: Have carriers, leashes, and pet supplies ready for rapid evacuation
Childcare facilities: Ensure schools and daycares in tsunami zones have comprehensive evacuation plans
Evacuation assistance: Register with local emergency management if you’ll need evacuation assistance

Real-World Lessons: Learning from Past Events

Historical submarine landslide-triggered tsunamis provide valuable lessons for coastal residents. The 1998 Papua New Guinea tsunami, which killed over 2,200 people, demonstrated how a relatively small earthquake could trigger a devastating submarine landslide and tsunami with minimal warning time. Similarly, the 2018 Sulawesi tsunami in Indonesia showed how local geography can amplify tsunami impacts when underwater landslides occur in enclosed bays.

From studying these and other historical events, emergency management experts have identified several key lessons that can improve survival rates. Chief among these is the importance of immediate evacuation upon feeling earthquake shaking or observing unusual ocean behavior, rather than waiting for official warnings.

Key Lessons from Historical Events:

Natural warnings: Don’t wait for official warnings—evacuate immediately if you feel strong shaking or notice unusual ocean behavior
Evacuation speed: The Papua New Guinea tsunami arrived within minutes of the triggering event
Geographic amplification: Bays, inlets, and narrow channels can amplify tsunami waves
Infrastructure vulnerability: The 2011 Japan tsunami showed how critical infrastructure can be compromised
Long-term displacement: Many communities faced months or years of displacement
Multiple waves: Tsunamis typically involve multiple waves over several hours
Secondary hazards: Contaminated water, fires, and hazardous material spills often follow tsunami events

Conclusion: Building Resilience Against Submarine Landslides

Preparing for submarine landslides and their resulting tsunamis requires a comprehensive approach that combines understanding, planning, and community involvement. While these events can be devastating, proper preparation significantly improves survival rates and recovery outcomes. By understanding the risks, creating detailed emergency plans, maintaining appropriate supplies, and learning from historical events, coastal residents can build resilience against one of nature’s most sudden and destructive forces.

The most prepared coastal communities approach submarine landslide and tsunami preparedness as an ongoing process rather than a one-time event. Regular drills, updated emergency plans, and continued education ensure that preparedness becomes ingrained in coastal living. While we cannot prevent submarine landslides, we can certainly minimize their human impact through knowledge and preparation.

For coastal residents seeking to enhance their emergency preparedness, Batten’s comprehensive emergency preparation products provide essential tools and supplies specifically selected for coastal hazards.

Final Preparedness Checklist:

Understand your risk level and local tsunami hazard zones
Create and practice a family emergency plan with clear evacuation routes
Maintain appropriate emergency supplies in accessible locations
Know both official warning systems and natural warning signs
Consider structural modifications to improve home resilience
Review insurance coverage and maintain proper documentation
Participate in community preparedness efforts
Develop a recovery plan for the aftermath of an event
Account for vulnerable family members in your planning
Stay informed about local emergency management recommendations

Remember: When it comes to submarine landslide-generated tsunamis, immediate evacuation to higher ground remains the single most important survival strategy.

Want to enhance your home’s emergency preparedness? Browse Batten’s expert-recommended emergency preparation products and start protecting what matters most.

Sources used for this article:

National Oceanic and Atmospheric Administration (NOAA) Tsunami Program, https://www.tsunami.gov/

U.S. Geological Survey (USGS) Coastal and Marine Hazards and Resources Program, https://www.usgs.gov/programs/cmhrp

Federal Emergency Management Agency (FEMA) Tsunami Preparedness, https://www.ready.gov/tsunamis

Woods Hole Oceanographic Institution, Marine Geohazards Research, https://www.whoi.edu/