What to do in an earthquake: Drop, Cover, Hold On

Earthquakes strike without warning when tectonic stress along crustal fault lines exceeds the frictional shear strength of rock, releasing massive seismic wave energy in seconds. Primary compressional P-waves produce sudden vertical jiggling, rapidly followed by destructive transverse S-waves and rolling surface Rayleigh and Love waves that subject structures to violent horizontal acceleration. In developed nations with modern seismic building codes, total structural collapse is rare. Epidemiological trauma data confirms that the vast majority of earthquake injuries and fatalities result from falling non-structural architectural elements, shattered facade glass, toppled heavy furniture, and individuals losing balance and falling while attempting to flee shaking buildings.

Executing the scientifically validated Drop, Cover, and Hold On protocol protects your vital cranial and cervical spine regions, stabilizes your body against ground acceleration, and mitigates blunt force trauma.

Urgent action checklist: the first 60 seconds

When the ground begins trembling, rumbling, or violently shaking:

1. Drop immediately to your hands and knees:
   • Drop down onto the floor wherever you are. Violent seismic ground acceleration knocks walking or running individuals off their feet, causing severe hip fractures, dislocated joints, and head concussions. Dropping to your hands and knees lowers your center of gravity while allowing you to crawl if necessary.
2. Cover your head and neck:
   • Crawl beneath a sturdy piece of furniture, such as a heavy dining table, oak desk, or solid workbench.
   • If no shelter is within 2 to 3 steps, crawl next to an interior load-bearing partition wall away from exterior glass windows, heavy suspended light fixtures, and tall freestanding bookcases. Cover your head and cervical spine with both arms, keeping your face tucked toward your chest.
3. Hold On to your shelter:
   • Grasp a sturdy table leg firmly with one hand. As seismic waves toss and shift the table across the room, move with your shelter so you remain shielded underneath. Keep your other arm clamped over your head and neck.
4. Stay in place until all shaking stops:
   • Never attempt to run outside while shaking is active. Falling roof tiles, decorative parapets, chimney bricks, and shattered window glass rain down directly onto exterior sidewalks and building exit doors.
5. Put on sturdy shoes before walking through debris:
   • Once shaking ceases, put on thick closed-toe shoes or work boots immediately. Walking across shattered window glass, broken dishware, and fallen drywall screws is a primary cause of disabling lacerations during the immediate aftermath.

Tactical decision flow for seismic ground shaking

flowchart TD
    Step1["<b>flowchart TD</b>"]
    Step2["<b>Root[&quot;<b>+-------------------------------------------------------------------------+</b>&quot;</b>"]
    Step3["<b>Check{&quot;| TACTICAL SEISMIC GROUND SHAKING FLOW | | v | SEISMIC SHAKING DETECTED | | v | WHAT IS YOUR IMMEDIATE LOCATION? | / | \ / | \ v v v INDOORS OUTDOORS IN VEHICLE | | | v v v | DROP, COVER, | | OPEN AREA | | PULL OVER SAFELY | | HOLD ON | | RETREAT | | - Stop clear of | | - Crawl under | | - Move | overpasses, wires | | sturdy table | away from | - Set parking brake | | - Grasp leg | facades | - Stay inside with | | - Shield neck | - Drop down | seatbelt fastened | \ | / \ | / v v v | SHAKING STOPS</b><br/>POST-SHAKE HAZARDS| | v | COASTAL LOCATION WITH STRONG SHAKE| / \&quot;}"]
    Step4["<b>Root --> Check</b>"]
    Step5["<b>YesNode[&quot;<b>/</b><br/>v<br/>| IMMEDIATE TSUNAMI EV<br/>| - Move on foot to hi<br/>| (30 meters / 100 f&quot;</b>"]
    Step6["<b>Check -->|Yes| YesNode</b>"]
    Step7["<b>NoNode[&quot;<b>\</b><br/>v<br/>ACUATION | | RESIDENTIAL LIFE SAFETY CHECK |<br/>gh ground | | - Put on sturdy closed-toe shoes |<br/>eet up) | | - Sniff for gas; shut off meter |&quot;</b>"]
    Step8["<b>Check -->|No| NoNode</b>"]
    Step1 --> Step2
    Step2 --> Step3
    Step3 --> Step4
    Step4 --> Step5
    Step5 --> Step6
    Step6 --> Step7
    Step7 --> Step8

Seismic intensity and structural damage classification matrix

While the moment magnitude scale (Mw) calculates the total physical energy released at the earthquake hypocenter, the Modified Mercalli Intensity (MMI) scale measures localized surface shaking intensity, human perception, and structural damage at specific geographic coordinates.

Drop, Cover, and Hold On: the biomechanics of survival

The Drop, Cover, and Hold On protocol was developed through rigorous engineering analysis and historical trauma evaluations conducted by the United States Geological Survey (USGS), the Federal Emergency Management Agency (FEMA), the American Red Cross, and international earthquake engineering research consortia.

flowchart TD
    Step1["<b>| | [ARM 1</b><br/>GRASP LEG] | |"]
    Step2["<b>| | [ARM 2</b><br/>SHIELD NECK] | |"]
    Step3["<b>| FLOOR ======= [ KNEEL ON HANDS & KNEES ] ===================== |</b>"]
    Step1 --> Step2
    Step2 --> Step3

Debunking dangerous earthquake myths

• The doorway myth:
  • Modern interior doors are lightweight architectural partitions fastened with finishing nails into standard pine wall studs. A doorway is no stronger than any other part of a modern building and does not protect you from flying debris. In addition, violent shaking causes doors to swing wildly, crushing fingers and striking occupants.
• The Triangle of Life myth:
  • The widely circulated internet concept advising people to lie down beside heavy objects (such as refrigerators, filing cabinets, or sofas) to create a supposed void space is dangerously flawed.
  • During earthquakes, heavy furniture shifts, slides across floors, and topples over, crushing individuals lying adjacent to them. Furthermore, in modern buildings that do not experience pancake collapse, falling ceiling tiles, lighting troffers, and broken glass strike people who remain exposed on the floor. Crawling beneath a sturdy table provides proven overhead ballistic deflection.

Situational sheltering protocols

Your physical environment dictates specific sheltering modifications:

If you are in bed

• Stay in bed:
  • Do not attempt to jump out of bed and run across a dark bedroom in the middle of violent shaking. Shaking will knock you onto the floor, and the room will be strewn with broken mirror glass and lamp fragments.
  • Roll face down onto your stomach, pull your knees slightly up, and pull your pillow or mattress firmly over your head and cervical spine.
• Exception: Move only if a heavy unanchored ceiling fan, heavy framed art, or an unreinforced stone chimney is mounted directly above your bed.

If you are outdoors

• Move to an open clearing:
  • Walk away from building perimeters, plate-glass storefronts, streetlights, overhead electrical utility lines, and brick masonry facades.
  • The most hazardous zone is within 3 to 5 meters (10 to 16 feet) of a building's exterior walls, where falling parapets, decorative masonry cladding, and shattered window panes crash onto the sidewalk.
  • Once in a clear area, drop to the ground and shield your head until shaking stops.

If you are in a motor vehicle

• Pull over safely:
  • Safely steer the vehicle toward the right shoulder or road edge.
  • Avoid stopping directly beneath highway overpasses, bridges, elevated road ramps, hanging traffic light gantries, large overhead billboards, or electrical utility poles.
• Stay secured inside the vehicle:
  • Shift into Park and engage the emergency parking brake.
  • Keep your seatbelt securely buckled. The vehicle's steel body, laminated safety glass, and independent suspension system absorb substantial seismic shocks and protect you from low-mass falling debris.

If you use a wheelchair or mobility device

• Lock, Cover, and Hold On:
  • Engage the wheel locks or mechanical brakes on your wheelchair or walker immediately.
  • Lean your body forward as low as possible, tuck your head between your knees, and cover your head and neck with your arms, a heavy bag, a hardcover book, or an article of clothing.
  • Hold that position until ground shaking ceases.

Post-shaking secondary hazards: fire, gas, and electrical lines

Historically, conflagrations (post-earthquake fires) fueled by broken gas lines and ignited by electrical arcing cause destruction comparable to or greater than the original ground shaking.

• [ ] NATURAL GAS METER INSPECTION
  • Sniff for rotten egg odor (mercaptan) or listen for loud hissing
  • IF ODOR DETECTED: use an adjustable crescent wrench to rotate the
  • gas valve lug 90 degrees perpendicular to the incoming pipe
  • IF NO ODOR OR LEAK: LEAVE GAS ON (utilities take weeks to restore)
• [ ] ELECTRICAL SYSTEM DEFENSE
  • If you smell gas, do NOT operate light switches or spark breakers
  • If structure has physical damage, turn off main electrical breaker
• [ ] DOWNED POWER LINE STEP-POTENTIAL
  • Treat all fallen power lines as energized 7,200V distribution wires
  • Maintain a strict exclusion perimeter of 10 meters (33 feet)
  • Electricity radiates through ground via concentric step-potential
  • If trapped near line: hop on one foot or shuffle with feet touching

Coastal tsunami threat recognition and immediate evacuation

If you are located along an ocean coast, enclosed bay, or low-lying coastal inlet when an earthquake strikes, seismic shaking serves as your natural warning of an impending tsunami.

• Natural tsunami warning signs:
  • Ground shaking that lasts for longer than 20 to 30 seconds.
  • Ground shaking so violent that it is difficult or impossible to stand.
  • A rapid, abnormal withdrawal of the ocean exposing reefs, harbors, and the seafloor.
  • A loud, roaring locomotive sound emanating from the ocean horizon.
• The mandatory coastal evacuation rule:
  • Never wait for official sirens, civil defense broadcasts, or wireless phone alerts. A localized near-field tsunami generated by an offshore fault rupture can strike the coastline within 10 to 15 minutes of the earthquake.
  • Evacuate immediately on foot. Run to high ground at least 30 meters (100 feet) above sea level, or travel at least 3 kilometers (2 miles) inland away from coastal shorelines.
  • Evacuate on foot rather than driving, as roadways become gridlocked with panicked traffic and collapsed bridge ramps.

Aftershock readiness and structural safety triage

Earthquakes are never isolated, singular events. An initial mainshock alters tectonic stress distributions across the fault zone, triggering dozens or hundreds of aftershocks governed by Omori's law (aftershock frequency decreases inversely with time).

• Aftershock reality:
  • Strong aftershocks can strike minutes, hours, days, or months following the mainshock.
  • An aftershock measuring one magnitude unit lower than the mainshock (such as a magnitude 6.0 aftershock following a 7.0 mainshock) releases enormous energy capable of completely collapsing structures that were cracked or weakened by the first shock.
• Structural safety triage (Red Tag vs Green Tag):
  • Inspect your home from the exterior before re-entering. Look for deep diagonal (X-shaped) structural cracks in concrete foundation stem walls, visible separation of the framing from the foundation, leaning chimneys, or unseated floor joists.
  • If structural damage is visible, do not re-enter. Sleep in a safe outdoor clearing or designated emergency community shelter until municipal building inspectors certify the property.

Seismic structural mitigation and non-structural hazard fastening

Preparing a home before an earthquake strikes eliminates over 80 percent of domestic injury vectors:

• [ ] WATER HEATER BRACING
  • Strap the water heater tank securely to wall framing studs with
  • two heavy-gauge galvanized steel straps (top third and bottom)
  • Install flexible corrugated stainless steel gas and water lines
• [ ] HEAVY FURNITURE ANCHORING
  • Anchor tall bookcases, armoires, and china cabinets into wooden
  • wall studs using heavy L-brackets or nylon seismic straps
  • Secure large flat-screen televisions to consoles or wall studs
• [ ] CABINET LATCH HARDWARE
  • Install mechanical or positive magnetic latches on kitchen cabinet
  • doors to prevent dishes and glassware from flying across rooms
• [ ] STRUCTURAL FOUNDATION BOLTING
  • In older wood-frame homes, verify that sill plates are bolted to
  • the concrete foundation with anchor bolts every 1.8 meters (6 ft)
  • Sheathe cripple walls with structural plywood to prevent collapse

Frequently asked questions

Should I stand in a doorway during an earthquake?

No. Standing in a doorway during an earthquake is outdated advice that is no longer recommended. In modern homes and buildings, doorways are not structurally stronger than any other part of the wall and offer no overhead protection from falling light fixtures, ceiling tiles, or flying debris. In addition, the violent motion of an earthquake causes doors to swing rapidly back and forth, which can crush hands or knock you to the floor. Crawling beneath a sturdy table or desk using Drop, Cover, and Hold On provides superior protection.

What should I do if an earthquake strikes while I am in bed?

Stay in bed. Turn onto your stomach to protect your vital organs and pull a pillow or mattress firmly over your head and cervical spine. Attempting to get out of bed and run across a shaking room in the dark exposes you to severe falls and deep lacerations from shattered mirror and window glass scattered on the floor. Move only if a heavy unanchored object, such as a heavy lighting fixture or stone masonry, hangs directly overhead.

When should I shut off my home's natural gas valve after an earthquake?

Only shut off your natural gas meter if you smell the rotten-egg odor of mercaptan, hear a loud hissing sound of escaping gas, or observe visible physical damage to your gas pipes or appliances. If you detect a leak, use an adjustable wrench to turn the gas valve lug a quarter turn (90 degrees) until the lug sits perpendicular to the incoming gas pipe. If there is no smell or sound of leaking gas, leave the gas turned on. Once gas is shut off, only certified gas utility technicians can legally and safely inspect your lines and relight pilot lights, which can take weeks during a widespread disaster.

Why is running outside during an earthquake dangerous?

Attempting to run out of a building during active shaking is one of the leading causes of earthquake injuries and fatalities. The exterior perimeter of a building, particularly doorways and sidewalks, is the most lethal zone. High-velocity ground shaking snaps unreinforced masonry parapets, topples roof chimneys, dislodges decorative stone cladding, and shatters multi-story plate glass windows, raining heavy debris directly down onto building entrances and pedestrian walkways. Stay indoors under cover until shaking stops completely.

How do I know if an earthquake will cause a tsunami?

If you are near a coastal shoreline and experience severe earthquake shaking that lasts for longer than 20 to 30 seconds or makes it difficult to stand, you must treat the event as an immediate natural tsunami warning. Other physical signs include a rapid, abnormal withdrawal of the ocean exposing the seafloor, or a loud roaring sound approaching from the sea. Do not wait for official civil defense sirens or telephone alerts; immediately evacuate on foot to high ground at least 30 meters (100 feet) above sea level or 3 kilometers (2 miles) inland.

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