How Earthquakes Cause Fires (and How to Reduce Risk)

In earthquake country, one of the greatest dangers comes not from the shaking itself but from what follows: fire. Historically, fire has caused more earthquake destruction than the quakes directly — and the Bay Area's seismic risk makes this a critical thing for property owners to understand. Here is how earthquakes cause fires, and how to reduce your risk.

SECTION 01Why Earthquakes Cause Fires

Earthquakes create the perfect conditions for fire by simultaneously creating ignition sources and disabling the systems that would normally fight a fire:

• Ruptured gas lines — shaking breaks natural gas pipes and connections, releasing gas that ignites from any spark
• Damaged electrical systems — severed and shorted wiring creates sparks
• Toppled heat sources — water heaters, stoves, and heaters knocked over onto flammable materials
• Broken water mains — the same quake that starts fires often cuts the water supply needed to fight them
• Blocked access — damaged roads delay firefighters

SECTION 02The Historical Lesson

The 1906 San Francisco earthquake is the defining example: the fires that followed the quake caused the majority of the destruction, burning for days in part because the water mains had ruptured. This pattern — quake, then fire, then no water to fight it — is exactly what makes earthquake fire risk so severe, and why it remains a central concern in Bay Area disaster planning.

SECTION 03Reducing Your Earthquake Fire Risk

1. Know how to shut off your gas — keep a wrench near the meter and learn the procedure
2. Strap your water heater — securing it prevents it from toppling and rupturing gas/water lines
3. Consider an automatic gas shutoff valve — these close the gas supply automatically when shaking is detected
4. Secure heavy appliances and heat sources — anchoring reduces the chance they topple
5. Maintain your electrical system — especially in older homes with aging wiring
6. Keep fire extinguishers accessible — for the small fires you may be able to stop early

SECTION 04After an Earthquake Fire

Properties affected by earthquake-related fire face the same fire, smoke, and water damage as any fire — often compounded by structural damage from the quake itself. Fast professional assessment and restoration is essential, both to save what can be saved and to safely evaluate a structure that has been through both a quake and a fire. Allied provides fire and structural damage restoration across the seismically active Bay Area.