Earthquake

Earthquakes give no warning. The 1994 Northridge earthquake — magnitude 6.7, striking Los Angeles at 4:31 AM — killed 57 people, caused 1,500 serious injuries, and caused $20 billion in property damage in under 30 seconds. The Loma Prieta earthquake in 1989 killed 63 people and injured 3,700 in Northern California. In both events, the research showed that most injuries came not from building collapse but from falling objects, broken glass on bare feet, and people moving when they should have sheltered.

The lesson from every major US earthquake is consistent: buildings perform better than people give them credit for, and the injuries that do happen are largely preventable through pre-event preparation. This is one of the few disaster scenarios where the decisions you make before the shaking starts — not during it — determine most of the outcome.

Seismic risk geography

The continental US has five high-risk seismic zones:

Pacific Coast: The Cascadia Subduction Zone (Washington, Oregon, Northern California) poses the most severe long-term risk — a full-rupture Cascadia event could reach magnitude 9.0 and cause catastrophic shaking over 700 miles (1,130 km) of coastline. The San Andreas Fault system in California generates frequent significant quakes and carries a high probability of a major event in the next 30 years, per USGS assessments.
Intermountain West: Utah, Nevada, Idaho, and Montana have significant fault systems with historical records of major quakes.
New Madrid Seismic Zone: Centered on the Mississippi River valley (Missouri, Arkansas, Tennessee, Kentucky), this zone produced some of the largest historical earthquakes in North American history — the 1811-1812 New Madrid sequence reached estimated magnitude 7.5-8.0, causing the Mississippi River to temporarily flow backward.
Alaska: Generates more large earthquakes than any other state. The 1964 Good Friday earthquake was magnitude 9.2, the second-largest ever recorded.
Hawaii: Volcanic-related seismicity, with significant events associated with volcanic activity on the Big Island.

Know your seismic zone. USGS provides county-level hazard maps for free at usgs.gov. Your county's emergency management office publishes local hazard assessments.

Before the shaking: home hardening

This is where preparation pays off most. The fixes are cheap; the injuries they prevent are not.

Secure heavy furniture: Bookshelves, filing cabinets, dressers, and water heaters are projectiles in a strong quake. Anchor them to wall studs with L-brackets and flexible safety straps rated for seismic use. Furniture not anchored to studs (anchored only to drywall) will pull free. Hardware stores carry furniture anchor kits; the total cost for a typical home is inexpensive. A bookshelf loaded with books can weigh 200-400 pounds (90-180 kg) — enough to be fatal if it falls on an adult.

Secure the water heater: Gas water heaters are the #1 source of post-earthquake fires. Movement during shaking ruptures the gas connection. Strap the water heater to wall studs with at least two metal straps — one in the upper third, one in the lower third of the tank. This is required by code in California and recommended everywhere.

Relocate heavy items: Move heavy objects from upper shelves to lower shelves. Keep nothing heavy directly above sleeping areas, sofas, or places where people regularly sit or sleep.

Latched cabinets: Install childproof latches on kitchen cabinets to prevent doors from flying open and throwing dishes and glass. After a quake, barefoot evacuation through broken glass is one of the most common injury mechanisms. Keep shoes in a reachable position near your bed — specifically for this reason.

Gas shutoff knowledge: Locate your main gas shutoff valve and keep an adjustable wrench or dedicated gas shutoff tool nearby. Know how to turn it off: a quarter-turn parallel to the pipe is on; a quarter-turn perpendicular to the pipe is off. Turn it off only if you smell gas, see damaged gas lines, or hear a hissing sound — turning it off without cause requires a utility technician to restore service.

Water heater shutoff and isolation valve: Know the location of your water heater isolation valve separately from the main house valve.

Do not shut off gas unless you smell it

Turning off gas preemptively and then being unable to reach the utility to restore it means no heat and no hot water for days to weeks after a quake, when service crews are overwhelmed. Shut off gas only in response to evidence of a leak — smell, sound, or visible line damage. A gas fire following an earthquake is almost always preceded by a detectable smell or sound.

During shaking: Drop, Cover, and Hold On

Federal, state, and local emergency management agencies are unanimous on this: Drop, Cover, and Hold On.

People who move more than 10 feet (3 m) during shaking are significantly more likely to be injured than those who shelter in place. The doorway myth — standing in a doorway for protection — is false. Modern doorways offer no special structural advantage and leave you exposed to swinging doors, breaking glass, and falling debris.

Drop: Get to your hands and knees. This position prevents being knocked off your feet and keeps you mobile.

Cover: Get under a sturdy table or desk if one is within arm's reach. If not, cover your head and neck with your arms and hands. Move against an interior wall away from windows.

Hold On: If sheltering under furniture, hold on to it and be ready to move with it if it shifts. Stay down until shaking stops completely.

Specific situations:

In bed: Stay in bed. Cover your head and neck with your pillow. Rolling onto the floor puts you in the path of falling debris with no protection.
Outdoors: Move away from buildings, power lines, trees, and streetlights. Drop to the ground and stay there.
In a vehicle: Pull over safely away from buildings, trees, overpasses, and power lines. Stay inside with your seatbelt fastened. After shaking stops, proceed carefully — roads may be damaged.
In a multistory building: Do not use elevators. Take cover as above; the greatest risk from collapsing buildings is in stairwells and elevators, not in open floor areas.

Field note

Run a household earthquake drill at least once a year. The gap between knowing to drop-cover-hold and actually doing it instinctively is filled by practice, not reading. The drill takes three minutes. If your household has children, they should be able to execute the response without being told — the adult may be in another room when the shaking starts. Make the drill a habit, not a one-time event.

Immediately after: the critical 60 minutes

More people die in the hour after a major earthquake than during the shaking itself, from fires, structural collapse of already-damaged buildings, and injuries treated incorrectly.

Before moving: Check yourself and others for injuries. Control serious bleeding before doing anything else. Do not move anyone with a suspected spinal injury unless there is immediate life threat.

Check for gas: Smell carefully. If you detect gas, open windows, leave the building, and call the gas company from outside. Do not use light switches, matches, lighters, or anything that can create a spark.

Check for fires: Check the stove, water heater connections, and fireplace area. Small fires caught in the first minutes are manageable; fires detected 30 minutes later are structural.

Assess before re-entering: After a major quake, do not re-enter a building that shows visible structural damage — cracked foundation, shifted walls, collapsed roof sections, chimney damage. A structurally compromised building that survived the main shock may not survive an aftershock. Red- and yellow-tagged buildings will be identified by inspectors after a major event, but you'll be waiting hours or days for that assessment in a significant earthquake.

Aftershocks: Expect them. After a major earthquake, aftershocks exceeding magnitude 6.0 can occur for days to weeks. The largest aftershock is typically about one magnitude unit smaller than the main shock — a magnitude 7.0 main shock may produce aftershocks reaching magnitude 6.0. Take cover during every aftershock as you would during the main event.

Post-earthquake supply requirements

Federal Emergency Management Agency (FEMA) recommends 72 hours of supplies as a minimum; most emergency managers in seismically active regions now recommend 14 days. The infrastructure damage that follows a major earthquake — ruptured water mains, damaged electrical systems, blocked roads, damaged natural gas distribution — routinely exceeds the 72-hour recovery window.

Water: The most critical post-earthquake supply. Municipal water mains fracture. Your home plumbing may lose pressure even if the mains are intact. Store a minimum of 14 gallons (53 L) per person — enough for 14 days at 1 gallon (3.8 L) per person per day.

In earthquake-prone areas, fill your bathtub immediately after a major quake if water pressure is still running — you may have only minutes before pressure is lost. A WaterBOB bladder (a bathtub liner designed for emergency water storage) can be filled in minutes and holds up to 100 gallons (378 L).

Food: 14-day supply of shelf-stable food that doesn't require cooking or heating. After a major quake, your gas may be off and your electrical panel may be tripped or damaged. Cold meals from shelf-stable food are your fallback. See the food storage foundation for quantity planning.

First aid supplies: Earthquake injuries are predominantly cuts (broken glass), bruising, and fractures. Your kit needs wound irrigation capability, bandaging supplies, splinting materials (SAM splints are affordable and versatile), and pain management. Hospitals may be overwhelmed or inaccessible after a major event. Review the medical foundation for trauma kit guidance.

Communication: Cell networks overload within minutes of a major earthquake as millions of people try to call simultaneously. Text messages get through when calls do not — send texts to check in. A battery-powered National Oceanic and Atmospheric Administration (NOAA) weather radio provides official emergency broadcasts when cellular is down.

Structural vulnerability and retrofitting

Not all homes are created equal in seismic risk. Two structure types are particularly vulnerable:

Soft-story buildings: Residential buildings with large open spaces on the ground floor (parking garages, large windows, commercial spaces) and living units above. The ground-floor "soft story" collapses under lateral load. Many older California apartment buildings are this type. If you live in a soft-story building, know its retrofit status — California has mandatory retrofit programs in many jurisdictions.

Cripple-wall homes: Pre-1940 wood-frame homes built on short exterior foundation walls (cripple walls) without structural sheathing can collapse sideways. Bolting the mudsill to the foundation and adding plywood sheathing to cripple walls is a moderate investment retrofit that dramatically reduces collapse risk. A licensed contractor or the California Earthquake Authority's Brace + Bolt program can provide assessment.

Preparedness checklist

With your home hardened and your supplies staged, the final piece is a household communication plan — knowing how to reconnect with family members who may be at school, work, or in transit when a quake strikes. A pre-established communications plan and designated out-of-area contact solves this problem completely before it arises.