The Big One: What Happens After the Shaking Stops?
Updated: 15 hours ago
Earthquake preparedness isn't about predicting disaster. It's about making sure a disaster doesn't become a personal catastrophe.
By Greenisms | The Ecosystem Recipe Company
Imagine it's 10:17 on a Tuesday morning in Southern California.
You're making coffee, answering emails, walking the dog, or getting ready for work.
Then the ground begins to move.
At first, you wonder whether it's another small earthquake. But the shaking gets stronger. Cabinets open. Glass breaks. Furniture moves. The lights go out.
You drop, cover, and hold on.
Eventually, the shaking stops.
You're alive. Your house is still standing.
But the earthquake isn't over.
The power is out. The water pressure is dropping. Cell service is unreliable. Your refrigerator has stopped running. Traffic signals are dark, and emergency responders are overwhelmed.
What happens next?
That depends less on what you do during the earthquake than on what you've already done before it.
1. The Big One Is Not Science Fiction
Southern California sits within one of the most seismically active regions in the United States.
In 2008, the U.S. Geological Survey and its research partners developed the ShakeOut Scenario, modeling a plausible magnitude 7.8 earthquake along the southern San Andreas Fault.
The study involved more than 300 scientists, engineers, emergency planners, and other specialists.
Its findings were sobering.
Approximately 1,800 deaths
Approximately 53,000 injuries requiring emergency room care
Around 1,600 fires
Approximately $191 billion in economic losses, according to the later peer-reviewed scenario analysis
Widespread damage to buildings, transportation, utilities, and businesses
These are modeled consequences of one hypothetical earthquake, not a prediction of when or exactly how the next earthquake will occur.
But the underlying hazards are real, measurable, and well understood.
The most important lesson wasn't simply that earthquakes are dangerous.
It was that the consequences of an earthquake can extend far beyond the shaking itself. Aptly named, The Big One.
Source: U.S. Geological Survey, ShakeOut Scenario (2008); Porter et al., Earthquake Spectra (2011).
2. Two Households. One Earthquake. Very Different Outcomes.
Consider two hypothetical households living in the same neighborhood, experiencing the same earthquake.
Both homes remain structurally safe to occupy. Neither family suffers a serious injury.
But their experiences over the following week are remarkably different.
Household A: The Unprepared Home
The first hour
The family checks for injuries. Broken dishes cover the kitchen floor. A tall bookcase has fallen, blocking a hallway.
The power is out.
Nobody knows where the flashlight is, and their phones are already running low.
The first 24 hours
Water service becomes unreliable. They have a few bottles in the refrigerator, but no stored emergency supply.
The grocery store is closed. Gas stations cannot reliably pump fuel. The family begins driving around looking for supplies, adding to traffic congestion.
They can't contact a relative and have no agreed meeting location.
Day three
Food in the refrigerator has spoiled. The household has limited drinking water, no reliable means of preparing meals, and no clear information about when services will return.
A family member needs medication. The pharmacy is closed.
Stress begins affecting everyone's judgment.
Day seven
Even if utilities are returning, the family has spent days scrambling for basic necessities.
The earthquake caused the initial disruption.
Their dependence on uninterrupted infrastructure multiplied its consequences.
Household B: The Prepared Home
The first hour
The family checks for injuries and hazards.
Heavy furniture was secured beforehand, reducing the amount of falling debris. Flashlights are accessible, shoes are available, and everyone knows where emergency supplies are stored.
They check for gas, electrical, and water damage, and avoid unsafe areas.
The first 24 hours
Stored water and shelf-stable food are available. Phones can be charged using a portable battery.
The family sends short text messages to their designated contacts and monitors emergency information using a battery-powered radio.
They don't need to immediately travel in search of supplies.
Day three
They continue using their emergency provisions.
A prearranged plan helps them communicate with relatives. Their pets have food, water, and carriers or leashes available.
They can focus on helping neighbors rather than competing for scarce supplies.
Day seven
The family may still be uncomfortable. They may still face damage, displacement, financial losses, or disrupted employment.
Preparedness doesn't make an earthquake harmless.
But it gives them choices.
And choices are one of the most valuable resources available during an emergency.
3. The Real Threat Is Cascading Systems Failure
A modern household is not an isolated structure.
It's connected to electricity, water, wastewater, transportation, telecommunications, food distribution, healthcare, and financial networks.
Consider what happens when the electrical grid is disrupted:
Electricity failure → water pumping and communications disruption → reduced access to sanitation, information, and services → increased pressure on emergency responders.
The precise sequence depends on local infrastructure and backup systems, but the interdependence is unavoidable.
A water outage isn't just about drinking water. It can affect toilets, cooking, hygiene, hospitals, and firefighting.
A transportation disruption isn't just about commuting. It can prevent medical deliveries, food distribution, emergency access, and infrastructure repairs.
A telecommunications outage isn't just inconvenient. It can separate families and interfere with coordination.
This is what systems resilience addresses.
Resilience is the capacity to absorb disruption, maintain essential functions, adapt, and recover.
It isn't simply a matter of having more supplies.
It's about reducing the number of things that must go right for your household to function.
4. How Much Preparedness Is Enough?
California's Office of Emergency Services advises residents to prepare to be self-sufficient for at least three days.
For major earthquakes, the USGS recommends storing enough water for at least two weeks, allowing a minimum of one gallon per person per day.
For a household of four, that means:
Preparation period | Minimum stored water |
3 days | 12 gallons |
7 days | 28 gallons |
14 days | 56 gallons |
These quantities cover basic drinking and sanitation needs. Heat, medical requirements, pets, and other circumstances can increase demand.
But water is only one part of preparedness.
Consider six essential household systems:
Water: Can your household access safe drinking water if the taps stop working?
Food: Can everyone eat for several days without refrigeration, electricity, or grocery deliveries?
Energy: Can you maintain lighting, communication, and essential medical devices without grid power?
Shelter: Is your building seismically secure, and have you reduced falling-object hazards?
Health and sanitation: Do you have medications, first-aid supplies, hygiene provisions, and a safe way
to manage waste?
Communication and community: Does everyone know where to meet, how to exchange information, and who might need assistance?
A household doesn't need to become completely self-sufficient.
It needs enough redundancy that a single failure doesn't immediately become an emergency.
5. Preparedness Doesn't Have to Be Expensive
When people hear the word resilience, they may imagine generators, solar panels, expensive batteries, underground shelters, or enormous stockpiles.
Some technologies can provide meaningful protection, particularly for people with medical equipment or critical electricity needs.
But many of the most valuable improvements cost very little.
Securing a bookcase can prevent an injury.
Keeping sturdy shoes and a flashlight beside the bed can make navigating broken glass safer.
Storing additional drinking water can eliminate an urgent trip to a store.
Keeping medications, important documents, and pet supplies accessible can make evacuation considerably easier.
Knowing your neighbors can be as valuable as owning another piece of equipment.
The goal isn't to buy everything, but to be aware of what your needs might be.
The goal is to identify your most consequential vulnerabilities and address them in a practical order.
6. Your Neighbors Are Part of Your Emergency Infrastructure
There's another important difference between a prepared and unprepared community.
When every household is struggling to obtain the same basic supplies, local services face additional pressure.
But when more households can meet their immediate needs, communities have greater capacity to help people who cannot.
Someone with mobility limitations may need assistance evacuating.
An older neighbor may need help obtaining medication.
A family with young children may need clean water, food, or temporary shelter.
Preparedness creates opportunities for cooperation.
It doesn't eliminate the need for professional emergency services, but it can reduce avoidable demands on them.
A resilient community isn't one where everyone can survive alone. It's one where fewer people are forced to.
7. Earthquake Preparedness Is the Beginning of Home Resilience
Here's where the bigger picture becomes interesting.
Many of the systems that help a household recover from an earthquake also improve its ability to withstand other disruptions.
Stored water helps during supply interruptions.
Insulation and passive cooling can help during power outages and extreme heat.
Efficient appliances and appropriately designed backup electricity systems can reduce dependence on continuous utility service.
A diversified food supply helps when stores or transportation networks are disrupted.
Better building maintenance can reduce damage from storms and everyday deterioration.
In other words, earthquake preparedness isn't an isolated activity. It's an entry point into understanding how your home actually works.
A household that understands its dependencies is better positioned to make informed decisions about repairs, upgrades, efficiency, and emergency planning.
Not every improvement requires new technology.
And not every improvement needs to happen immediately.
The first step is knowing where you stand.
8. What Would Happen to Your Household?
Imagine that a major earthquake has just occurred.
Your home is still standing, but the electricity, running water, internet, and nearby grocery stores are unavailable for seven days.
Ask yourself:
How much safe drinking water do we actually have?
What food could we eat without electricity?
How long could we keep our phones charged?
Could we manage without working toilets or running water?
Are our pets and family members accounted for?
Which essential household systems would fail first?
If you don't know the answers, that's not a reason to panic.
It's a reason to investigate.
Start With Your Home, Not a Shopping List
The Greenisms Home Resiliency Planner is designed to help people examine their household systems, identify vulnerabilities, and explore practical improvements.
Rather than assuming every home needs the same emergency kit or expensive equipment, the goal is to understand your particular circumstances.
A renter in an apartment has different options from a homeowner with solar panels. A household with children, pets, or medical needs has different priorities from someone living alone.
Your preparedness plan should reflect those differences.
Explore the Greenisms Home Resiliency Planner and start identifying what your household depends on, what could fail, and what you can improve.
9. The Most Important Question Isn't When
Scientists cannot predict the exact date, time, and location of a future major earthquake.
But we know that damaging earthquakes will occur.
We also know that many of their consequences can be reduced through engineering, planning, education, and cooperation.
The objective isn't to eliminate every risk.
It's to avoid turning a predictable natural hazard into an unnecessarily devastating human disaster.
You don't need to prepare for the end of the world.
You need to prepare for a temporary interruption of the world you depend on.
Because the best time to discover what your home cannot function without is before those systems stop working.
Scientific References and Preparedness Resources
U.S. Geological Survey — The ShakeOut Scenario (2008). https://pubs.usgs.gov/of/2008/1150/
Porter et al. — The ShakeOut Scenario: A Hypothetical Mw 7.8 Earthquake on the Southern San Andreas Fault, Earthquake Spectra (2011). https://doi.org/10.1193/1.3563624
California Governor's Office of Emergency Services — Earthquake Preparedness. https://www.caloes.ca.gov/office-of-the-director/operations/planning-preparedness-prevention/seismic-hazards/earthquake-preparedness/
U.S. Geological Survey — Emergency Supplies for Earthquakes. https://www.usgs.gov/faqs/what-emergency-supplies-do-i-need-earthquake
Centers for Disease Control and Prevention — Earthquake Safety and Preparedness. https://www.cdc.gov/earthquakes/safety/index.html
California Earthquake Authority — Personal Earthquake Preparedness. https://www.earthquakeauthority.com/california-earthquake-risk/personal-preparedness
Safety note: During shaking, drop, cover, and hold on. Afterward, follow official instructions and evacuate damaged or hazardous structures. Never operate fuel-burning generators, grills, or camp stoves indoors. Shut off natural gas only when a leak or other signs of damage warrant it, following utility safety guidance.
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