Tsunami Warning Signs: What to Look For

Tsunami warning signs fall into two categories: official warnings disseminated by governmental agencies through technological systems, and natural warning signs observable by anyone on the coast. While official warnings saved thousands of lives in far-field tsunami events like the 2011 Tōhoku tsunami affecting distant Pacific shores, natural warning signs provide the only hope for survival in near-field tsunamis where waves arrive within 10-30 minutes—faster than official warnings can be processed and disseminated. The 2004 Indian Ocean tsunami killed over 227,000 people partially because most coastal residents didn't recognize natural warning signs: strong earthquake shaking, unusual ocean recession exposing seafloor, and the characteristic roaring sound of approaching tsunami waves.

Understanding what to look for requires distinguishing between normal ocean behavior and genuine tsunami indicators. The ocean naturally rises and falls with tides (typically 1-3 meters over 6 hours), experiences storm surge from weather systems, and shows wave action from winds. Tsunami warning signs differ fundamentally: abnormally rapid changes in sea level (meters in minutes rather than hours), ocean behavior disconnected from weather conditions, and physical phenomena (earthquake shaking, unusual animal behavior) that precede water-level changes. The key characteristic of natural tsunami warnings is their suddenness and departure from normal patterns—the ocean doesn't gradually recede, it rapidly withdraws as if someone pulled a drain plug.

The tragic reality is that most people who die in tsunamis either don't recognize warning signs or recognize them but fail to act with sufficient urgency. The 2004 Indian Ocean tsunami killed tourists on Thai beaches who watched the ocean recede with curiosity, walking out onto exposed seafloor to collect stranded fish—and were overtaken by the wave minutes later. The 2011 Tōhoku tsunami killed elderly Japanese who evacuated to designated evacuation centers that weren't high enough, mistakenly believing they'd reached safety. Survival depends on two factors: recognition of warning signs and immediate evacuation to adequate elevation without hesitation or delay.

This comprehensive guide examines natural tsunami warning signs with specific observable characteristics, official warning systems and how to interpret alerts, region-specific warning indicators, common misinterpretations that cost lives, animal behavior patterns, immediate action protocols, and case studies where recognition or ignorance of warning signs determined survival.

Natural Warning Signs: Nature's Tsunami Alert System

Warning Sign #1: Strong Earthquake Shaking (Near-Field Tsunamis)

For coastal areas near subduction zones, strong earthquake shaking is the most reliable tsunami warning sign.

Tsunami-Indicative Earthquake Characteristics:

• Duration: Shaking lasts 20+ seconds (most earthquakes last only 5-15 seconds)
• Intensity: Difficult to stand, objects falling from shelves
• Type: Rolling motion (subduction zone megathrust) rather than sharp jolts (strike-slip)
• Location: You are on the coast or within 10 km of ocean

Why Long Duration Indicates Large Magnitude:

• Earthquake duration correlates with fault rupture length
• M6.0 earthquake: ~10 km rupture, 5-10 seconds duration
• M7.0 earthquake: ~50 km rupture, 10-20 seconds duration
• M8.0 earthquake: ~200 km rupture, 30-60 seconds duration
• M9.0+ earthquake: ~500+ km rupture, 60-120+ seconds duration
• Only M7.0+ earthquakes reliably generate tsunamis
• If you're counting "one-one-thousand, two-one-thousand..." and reach 20+, evacuate immediately

Immediate Action Protocol:

1. Strong earthquake shaking lasting 20+ seconds = EVACUATE IMMEDIATELY
2. Do not wait for official warnings (won't arrive in time for near-field tsunami)
3. Do not wait to see if ocean recedes (wastes critical minutes)
4. Do not return to get belongings
5. Move to high ground (30+ meters / 100+ feet elevation) or 3+ km inland
6. If no high ground accessible, vertical evacuation to 3rd floor+ of reinforced concrete building

Historical Examples:

• 2011 Tōhoku, Japan: Earthquake shaking lasted 3-6 minutes depending on location—people who evacuated immediately during shaking survived, those who waited to see tsunami or gather belongings perished
• 2004 Sumatra, Indonesia: Earthquake shaking lasted 8-10 minutes—longest ever felt by most survivors—those who evacuated during or immediately after shaking survived, those in low-lying areas who didn't evacuate had ~15 minutes before wave arrival
• 1960 Chile: Main earthquake shaking lasted 10-12 minutes—residents near coast who evacuated during shaking survived despite waves arriving within 15 minutes

Warning Sign #2: Rapid Ocean Recession (Drawdown)

The most visually dramatic and widely recognized natural tsunami warning sign is the ocean rapidly receding, exposing seafloor that is normally underwater.

Observable Characteristics:

• Water level drops rapidly—meters in minutes rather than gradual tidal recession over hours
• Seafloor exposed that you've never seen before—rocks, coral, shipwrecks revealed
• Beach extends hundreds of meters farther out than normal low tide
• Boats in harbor suddenly grounded on exposed harbor bottom
• Strong seaward current—water flowing rapidly away from shore
• Occurs suddenly, often within 5-10 minutes

Why Drawdown Occurs:

• Tsunami waves consist of peaks (crests) and troughs (valleys)
• If wave trough arrives first, water level drops dramatically
• If wave crest arrives first, water rises without initial recession
• Whether trough or crest arrives first depends on direction to epicenter and coastal geometry
• Approximately 50% of tsunamis exhibit initial drawdown

How Much Time Before Wave Arrives:

• Drawdown is the trough of the first wave
• Wave period (time between waves): Typically 10-30 minutes for near-field tsunamis
• After drawdown, you have approximately 5-15 minutes before wave crest arrives
• This is NOT sufficient time for casual evacuation—must evacuate immediately

Fatal Curiosity:

• Human tendency: Walk out onto exposed seafloor to collect stranded fish, explore revealed areas
• 2004 Indian Ocean tsunami: Hundreds of tourists walked onto exposed Thai beaches, were overtaken by wave
• Historical accounts describe people collecting flopping fish on exposed harbor bottom minutes before tsunami arrival
• NEVER approach receding ocean—always evacuate to high ground

Immediate Action Protocol:

1. See ocean rapidly receding = EVACUATE IMMEDIATELY
2. Do not approach the water to investigate
3. Do not collect stranded fish or investigate exposed areas
4. Alert others nearby and evacuate as group if possible
5. Move to high ground or vertical evacuation building
6. Expect wave arrival within 5-20 minutes of initial recession

Warning Sign #3: Unusual Ocean Sounds

Approaching tsunami waves produce distinctive sounds that can be heard before waves are visible.

Characteristic Sounds:

• Roaring sound: Described as sounding like freight train, jet engine, or continuous thunder
• Hissing sound: Water rushing at high velocity creates hissing or whooshing noise
• Cracking/snapping: Sound of debris, trees, structures being broken by wave force
• Volume: Loud enough to be heard over normal ocean sounds, wind
• Direction: Sound comes from ocean direction, approaches

Why Tsunamis Are Loud:

• Enormous volume of water moving at high velocity (20-50 km/h onshore)
• Wave carries debris—trees, vehicles, buildings—which crash and grind together
• Water turbulence creates noise similar to rapids or waterfall
• Breaking and crushing of structures in wave path

How Much Warning Time:

• Sound travels ~340 meters/second in air
• If wave is 1 km away: ~3 seconds sound travel time
• If wave is 2 km away: ~6 seconds sound travel time
• Wave traveling 20-50 km/h covers 1-2 km in 1-3 minutes
• Hearing tsunami sound gives you typically 1-5 minutes before wave arrival
• Insufficient time for horizontal evacuation—seek immediate vertical evacuation

Survivor Accounts:

• 2004 Indian Ocean tsunami: Survivors describe "sound like a jet taking off" or "continuous roar that got louder and louder"
• 2011 Tōhoku tsunami: Videos capture roaring sound 2-3 minutes before wave visible in frame
• 1946 Aleutian tsunami (Hawaii): Survivors describe being woken by "sound of train approaching" before seeing water

Immediate Action Protocol:

1. Hear unusual roaring/rushing sound from ocean = Wave is 1-5 minutes away
2. Immediately seek highest ground or nearest reinforced building
3. If in building, go to highest floor possible
4. Do not look for the source of sound—evacuate immediately
5. Alert others as you evacuate

Warning Sign #4: Unusual Animal Behavior

While scientific evidence is limited, numerous tsunami survivors report unusual animal behavior minutes to hours before wave arrival.

Reported Animal Behaviors:

• Dogs: Barking frantically, refusing to go near beach, trying to lead humans inland
• Elephants (2004 Sri Lanka): Breaking chains, fleeing inland 30 minutes before wave arrival
• Birds: Mass evacuation from coastal areas, flying inland or to higher ground
• Fish and marine life: Jumping out of water, unusual surface activity
• Cattle and livestock: Trying to break fences, moving to high ground

Possible Explanations:

• Animals may sense earthquake P-waves (faster waves) before humans feel stronger S-waves
• Animals may detect changes in electromagnetic fields associated with fault rupture
• Animals may detect infrasound (very low frequency sound) from tsunami waves
• Enhanced sensitivity to ground vibrations, pressure changes
• Evolutionary advantage for coastal species to detect and flee tsunamis

Scientific Caveats:

• No rigorous controlled studies confirm animal early detection
• Selection bias: People remember unusual animal behavior when tsunami occurred, forget instances where animals acted strangely and no tsunami followed
• Post-hoc rationalization: Behavior interpreted as "warning" after event may be normal behavior
• Nevertheless: Consistent reports across multiple events suggest possible correlation

Practical Guidance:

• Don't rely solely on animal behavior—lack of unusual behavior doesn't mean no tsunami
• If animals are behaving strangely AND you experienced earthquake or observe ocean anomalies, take it seriously
• In coastal indigenous communities, animal behavior historically served as warning—traditional knowledge worth respecting

Warning Sign #5: Earthquake Aftershocks

Large earthquakes produce aftershocks—smaller earthquakes following main shock—that can themselves generate additional tsunamis.

Aftershock Tsunami Risk:

• Main shock (M8.0+) generates primary tsunami
• Large aftershocks (M7.0+) can generate secondary tsunamis
• Secondary tsunamis typically smaller than primary but still dangerous
• Can arrive minutes to hours after main tsunami

Historical Example—2011 Tōhoku:

• Main shock: M9.1 at 2:46 PM, generated primary tsunami
• M7.4 aftershock at 3:08 PM (22 minutes after main shock)
• M7.9 aftershock at 3:15 PM (29 minutes after main shock)
• M7.7 aftershock at 4:00 PM (74 minutes after main shock)
• Each capable of generating tsunami waves
• Complicated evacuation—people who returned after first wave caught by subsequent waves from aftershocks

Guidance:

• After major tsunami-generating earthquake, expect aftershocks for hours to days
• Each strong aftershock (felt shaking) may generate additional tsunami
• Remain at high ground until official all-clear issued (typically 12-24 hours minimum)
• Do not assume danger passed after first wave sequence

Official Warning Systems and Alert Interpretation

Wireless Emergency Alerts (WEA) / Mobile Phone Alerts

Modern tsunami warnings delivered directly to mobile phones via Wireless Emergency Alert system (US) or equivalent systems internationally.

Alert Characteristics:

• Distinctive sound: Loud alarm tone (different from normal notifications)
• Vibration: Phone vibrates even if on silent mode
• Text message: "TSUNAMI WARNING for [region]. Move to high ground or inland immediately. Do not wait. This is not a drill."
• Cannot be silenced—overrides Do Not Disturb settings
• Delivered to all phones in affected area regardless of carrier

What Alert Levels Mean:

TSUNAMI WARNING (Red Alert):

• Dangerous tsunami is imminent or occurring
• Destructive waves expected—inundation likely
• EVACUATE IMMEDIATELY to high ground
• Issued when: Confirmed tsunami generation, waves detected on buoys or tide gauges, OR large offshore earthquake with tsunami potential

TSUNAMI WATCH (Yellow Alert):

• Tsunami possible based on earthquake characteristics
• Waves may affect area but not yet confirmed
• Be ready to evacuate—monitor official information sources
• Move away from immediate beach areas as precaution
• Issued when: Large distant earthquake detected, tsunami possible but not confirmed for your area

TSUNAMI ADVISORY (Orange Alert):

• Tsunami capable of producing strong currents and coastal flooding
• Not typically life-threatening but hazardous
• Stay out of water, move away from beaches and harbors
• Wave heights typically 0.3-1.0 meters
• Dangerous for swimmers, boaters but unlikely to inundate far inland

Response Actions by Alert Level:

Tsunami Sirens

Coastal communities in tsunami-prone areas have installed outdoor warning sirens.

Siren Sound Patterns:

• Steady tone (3-5 minutes): General emergency alert—could be tsunami or other hazard
• Wailing/alternating tone: Specific tsunami warning in some jurisdictions
• Volume: Designed to be heard outdoors, may not be audible indoors with closed windows
• Coverage: Typically 1-2 km range from siren location

Siren Limitations:

• May not be audible indoors or over noise (traffic, machinery)
• Power outages may disable electric sirens (some have battery backup)
• Earthquake damage may disable siren infrastructure
• Don't indicate alert level (warning vs watch vs advisory)
• Some areas have monthly tests—learn test schedule to differentiate real alerts

Appropriate Response:

1. Hear tsunami siren = Evacuate immediately
2. Do not call emergency services asking for information (ties up lines needed for coordination)
3. Tune to local emergency radio (AM/FM) while evacuating for details
4. Assume WARNING level unless you can confirm otherwise

NOAA Weather Radio

NOAA Weather Radio broadcasts continuous weather information and emergency alerts on dedicated VHF frequencies (162.400-162.550 MHz).

Alert Characteristics:

• 1050 Hz attention tone (distinctive loud beeping)
• Activates receivers even when powered off (if battery-powered)
• Voice message detailing alert level, affected areas, recommended actions
• Continuously updated as situation evolves

Advantages:

• Works when cellular networks overloaded or damaged
• Battery-powered receivers continue working during power outages
• Provides detailed information (not just alert tone)
• More reliable than internet-dependent systems during infrastructure damage

Recommendation:

• Coastal residents should own NOAA Weather Radio with SAME (Specific Area Message Encoding) technology
• Program to alert for your county/parish
• Keep batteries fresh
• Test monthly on First Wednesday (NOAA test day)

Social Media and Smartphone Apps

Modern tsunami warnings rapidly disseminate via social media and dedicated apps.

Official Sources:

• National Weather Service (NWS) Twitter/X accounts
• Pacific Tsunami Warning Center (@NWS_PTWC)
• Local emergency management agencies
• FEMA mobile app
• Red Cross Emergency app
• Regional tsunami warning apps (Japan: J-Alert, Indonesia: IOS Gempa)

Advantages:

• Rapid dissemination—often faster than traditional media
• Interactive—can see real-time updates, affected areas
• Community reporting—people share observations (water recession, wave arrival)

Disadvantages and Cautions:

• Dependent on internet/cellular connectivity—fails if networks damaged or overloaded
• Misinformation spreads rapidly—verify through official sources only
• Can create false sense of security—relying on phone alerts when simpler natural signs (earthquake shaking) already present
• Time spent checking social media is time not spent evacuating

Best Practice:

• Use apps/social media for monitoring in watch/advisory situations
• In WARNING situations or after strong coastal earthquake: Evacuate immediately, check phone once at high ground
• Follow official accounts, not random social media users

False Warning Signs and Common Misinterpretations

What Is NOT a Tsunami Warning Sign

Distinguishing genuine tsunami indicators from normal ocean phenomena prevents false evacuations while ensuring real warnings are heeded.

Normal Tidal Changes:

• Gradual water level changes over 6 hours (tidal cycle)
• Predictable daily pattern (two high tides, two low tides per day typically)
• Tsunami drawdown is RAPID (minutes), tidal changes GRADUAL (hours)

Storm Surge:

• Water level rise associated with storms, hurricanes, low pressure systems
• Develops over hours as storm approaches
• Accompanied by wind, rain, weather changes
• Tsunami occurs WITHOUT weather changes—can happen on perfectly calm, sunny day

Seiches (Lake/Harbor Oscillations):

• Standing waves in enclosed or semi-enclosed bodies of water
• Can be triggered by weather, earthquakes (even distant earthquakes)
• Water sloshes back and forth within harbor or bay
• Period typically 5-30 minutes (similar to tsunami)
• Generally much smaller amplitude than tsunami (centimeters to 1-2 meters)
• Hazardous to boats but rarely causes significant coastal inundation

Rogue Waves:

• Unusually large wind-driven waves that appear in otherwise normal sea state
• Result from constructive interference of multiple wave trains
• Individual waves—not wave trains lasting hours like tsunami
• Hazardous to ships, coastal structures but don't flood far inland

Meteotsunami:

• Tsunami-like waves generated by atmospheric pressure changes (not earthquakes)
• Associated with severe thunderstorms, squall lines
• Can produce waves 1-3 meters high
• Localized—affect specific harbors or coastal segments
• Warning: Weather-related, not earthquake-related

Weak Earthquakes Don't Generate Tsunamis

A common misconception: Any coastal earthquake causes tsunami.

Reality:

• Only M7.0+ earthquakes reliably generate tsunamis
• M6.5-7.0: Rarely generate small local tsunamis (wave heights < 1 meter)
• M6.0-6.5: Virtually never generate tsunamis
• M < 6.0: No tsunami potential

Why Magnitude Threshold Exists:

• Tsunami energy proportional to displaced water volume
• Water volume = fault area × vertical displacement
• Smaller earthquakes have smaller fault areas and smaller displacements
• Insufficient water displacement to generate significant tsunami

Practical Guidance:

• Brief earthquake (< 15 seconds): No tsunami concern regardless of intensity
• Moderate earthquake (15-20 seconds): Low tsunami risk, monitor official warnings
• Long earthquake (20+ seconds): High tsunami risk, evacuate immediately

Regional Variations in Warning Systems

Japan: Most Advanced Tsunami Warning System

Japan experiences more tsunamis than any other nation and has developed the world's most sophisticated warning infrastructure.

J-Alert System:

• Satellite-based emergency warning broadcast system
• Delivers alerts to municipalities, media, mobile phones within 4-20 seconds of earthquake detection
• Four alert levels: Major Warning (giant tsunami expected, 5-10+ meters), Warning (tsunami expected, 2-5 meters), Advisory (tsunami expected, 0.5-2 meters), Forecast (no significant tsunami expected)
• Specific predicted wave heights and arrival times for each coastal segment

Tsunami Evacuation Buildings and Towers:

• Thousands of designated buildings marked with blue signs
• Evacuation towers: Dedicated structures (essentially tall platforms) in low-lying areas without natural high ground
• Emergency supplies, communications equipment pre-positioned
• Unlocked 24/7 for public access during emergencies

Public Education:

• Annual national tsunami drills
• School children practice evacuations regularly
• Historical tsunami markers showing past inundation levels
• Community knowledge: "Tsunami tendenko" (each person evacuate for themselves, don't wait for family—ensures rapid evacuation)

United States Pacific Coast: NOAA and State Systems

Two Warning Centers:

• National Tsunami Warning Center (Palmer, Alaska): Alaska, British Columbia, US West Coast
• Pacific Tsunami Warning Center (Honolulu): Hawaii, US Pacific territories

Warning Dissemination:

• Wireless Emergency Alerts to mobile phones
• NOAA Weather Radio
• Tsunami sirens (coastal communities)
• Emergency Alert System (TV/radio interruption)
• State/local emergency management notifications

Tsunami Hazard Zones:

• Mapped for West Coast, Alaska, Hawaii
• Blue evacuation route signs in hazard zones
• Assembly areas marked on high ground
• Public inundation maps available online

Indian Ocean: Post-2004 Improvements

Indian Ocean Tsunami Warning and Mitigation System (IOTWMS):

• Established 2006 after 2004 disaster
• Coordinated by UNESCO Intergovernmental Oceanographic Commission
• 26 participating countries
• Network of seismic stations, sea level stations, DART buoys

Challenges:

• Less developed than Pacific system
• "Last mile" problem: Warnings reach national centers but dissemination to coastal villages incomplete
• Limited public education in rural areas
• Language barriers across diverse region

Immediate Action Protocol: Step-by-Step

If You Experience Natural Warning Signs

Strong Earthquake Shaking (20+ seconds):

1. 0-30 seconds: Drop, Cover, Hold On (protect from earthquake shaking)
2. 30-60 seconds: Immediately after shaking stops, begin evacuation—do not wait for official alerts
3. 1-3 minutes: Move quickly but safely to high ground or vertical evacuation building—encourage others to evacuate
4. 3-5 minutes: Continue moving to higher ground—do not stop at first elevated area
5. 5-10 minutes: Reach target elevation (30+ meters) or 3rd+ floor of designated building
6. 10+ minutes: Remain at elevation until official all-clear (typically 3-12 hours)

Ocean Rapidly Receding:

1. Immediately: Turn away from ocean, shout "Tsunami!" to alert others
2. 0-2 minutes: Begin evacuation to high ground—do not approach receding water
3. 2-5 minutes: Continue evacuation—expect wave arrival within 5-15 minutes
4. 5+ minutes: Reach high ground, monitor for wave arrival

Unusual Ocean Sounds (Roaring):

1. Immediately: Seek nearest vertical evacuation—wave is 1-5 minutes away
2. 0-1 minute: Enter nearest reinforced building, go to highest floor
3. 1-3 minutes: Reach upper floors, move to seaward side of building (wave debris impacts from ocean side)
4. 3+ minutes: Brace for wave impact—hold onto fixed structures

If You Receive Official Alert

TSUNAMI WARNING (Red Alert):

1. Immediately evacuate to high ground (30+ meters elevation) or 3+ km inland
2. Take car if immediately available and roads clear—otherwise evacuate on foot
3. If driving and encounter traffic: Abandon vehicle, continue on foot
4. Bring: Phone, medications, water if immediately accessible—do not waste time gathering belongings
5. Remain at high ground minimum 3 hours after last wave—do not return until official all-clear

TSUNAMI WATCH (Yellow Alert):

1. Move away from immediate beach areas
2. Prepare for possible evacuation—identify evacuation route, gather emergency kit
3. Monitor official information sources (NOAA Weather Radio, mobile alerts, emergency broadcasts)
4. Be ready to evacuate immediately if upgraded to WARNING

TSUNAMI ADVISORY (Orange Alert):

1. Stay out of water—no swimming, surfing, boating
2. Leave beaches, harbors, marinas
3. Move to back-beach areas or beyond beach structures
4. Remain out of water for 3+ hours after advisory ends (strong currents persist)

Conclusion: Recognition + Action = Survival

Tsunami warning signs exist in two parallel systems: official technological warnings transmitted through government infrastructure, and natural warnings observable by anyone with knowledge of what to look for. Neither system alone guarantees survival—official warnings fail when earthquakes damage infrastructure or when tsunami arrival time is shorter than warning dissemination time, while natural warnings only save lives when recognized and heeded with immediate action. The 2004 Indian Ocean tsunami demonstrated the catastrophic consequences of lacking official warnings (227,898 deaths), while the 2011 Tōhoku tsunami demonstrated that even the world's most advanced warning system cannot prevent significant casualties (19,759 deaths) when natural factors create near-field tsunamis arriving within minutes of earthquake.

The most reliable tsunami warning sign for near-field events remains strong earthquake shaking lasting 20+ seconds. This single observable fact—countable by anyone—provides earlier warning than any electronic system can deliver and requires no technology, infrastructure, or official confirmation. The tragic irony is that this warning sign is simultaneously universal (works everywhere, requires no special equipment) and widely ignored (many coastal residents don't know the 20-second rule or fail to evacuate despite knowing it). Post-tsunami surveys consistently reveal that significant percentages of casualties occurred among people who felt the earthquake but didn't evacuate, or evacuated too slowly, or returned too soon.

Ocean recession—the most visually dramatic warning sign—paradoxically causes both survivals and deaths. Survivors recognize it as warning and evacuate; victims approach it with curiosity. The 2004 Indian Ocean tsunami killed tourists who walked onto exposed Thai beaches collecting stranded fish, overwhelmed by the wave minutes later. The fundamental lesson: The ocean does not recede to provide you with an opportunity to explore—it recedes because an enormous wave displaced that water elsewhere and that water will return violently. Any rapid ocean recession should trigger the same response as a strong earthquake: immediate evacuation without hesitation.

Official warnings work best for far-field tsunamis where hours of warning time allow organized evacuations. The 1960 Chile tsunami demonstrated this—despite devastating Chilean coastal areas within 15 minutes, Hawaii received 15 hours warning and Japan received 22 hours warning. Casualties in Hawaii (61 deaths) and Japan (142 deaths) resulted largely from warnings being ignored or inadequately heeded, not from failure to issue warnings. This creates the difficult challenge of warning systems: repeated warnings where tsunamis arrive but cause minimal damage (because warned populations evacuate, or tsunamis are smaller than predicted) create complacency that costs lives when the major event finally occurs.

For coastal residents in tsunami-prone regions, three levels of preparedness separate potential victims from survivors. First, know natural warning signs—20+ second earthquake shaking, rapid ocean recession, unusual roaring sounds—and commit to immediate evacuation upon observing any of them without waiting for official confirmation. Second, understand official warning systems in your region—what TSUNAMI WARNING vs ADVISORY vs WATCH means, how alerts are disseminated, what your specific evacuation route and assembly area are. Third, practice evacuations—actually walk or drive your route, time it, identify alternatives, eliminate obstacles. The difference between 8-minute evacuation and 15-minute evacuation is literally the difference between reaching high ground before the wave or being caught in inundation zone. Survival in the crucial 10-30 minute window between earthquake and wave arrival depends on decisions and actions that have been prepared, practiced, and committed to before the emergency occurs.