Earthquakes risk in New Hampshire

Earthquake Characteristics in New Hampshire

New Hampshire sits in a region of low to moderate seismic activity, far from the major fault lines of the western United States. The state's earthquake risk is rated level 2 out of 5, meaning that while earthquakes are possible, they are not a frequent or severe concern for most residents. According to the USGS Earthquake Hazards Program, New Hampshire has experienced dozens of small earthquakes over the past century, but most are too small to be felt or cause damage.

Unlike weather-related hazards, earthquakes have no season and can occur at any time of year, day or night. They are caused by shifting rocks deep underground along ancient fault zones that still exist in the northeastern United States. In New Hampshire, the most notable historical events include the 1940 earthquake near Ossipee (magnitude 5.6) and a 1982 event in the same area (magnitude 4.5), both of which caused minor damage such as cracked chimneys and plaster. More recent small tremors have been recorded in the central and southeastern parts of the state, but no large damaging quake has occurred in over 80 years.

Because the state's geology is typical of New England, earthquakes here are generally less intense than those in California or Alaska. However, the eastern United States has older, denser rock that can transmit shaking over larger distances. This means that even a moderate earthquake centered in New Hampshire could be felt across the state and into neighboring states. The areas most exposed to shaking are generally those with thicker, softer soils (such as river valleys and filled land), where ground motion can be amplified. Bedrock areas tend to experience less noticeable shaking.

State emergency officials, including New Hampshire Homeland Security and Emergency Management, plan for low-probability, high-impact events, and earthquakes are part of that planning. While the risk is low, being aware of the hazard is the first step to protecting your home.

How It Affects Homes

Earthquake shaking can damage homes in several ways, even when the quake is moderate. The most common types of damage in New Hampshire include:

• Cracked foundations – Shaking can cause hairline cracks in concrete foundation walls, which may worsen over time.
• Chimney damage – Brick or stone chimneys are especially vulnerable to ground motion and may collapse or crack.
• Broken windows and glass – Intense shaking can shatter windows and topple items like mirrors or picture frames.
• Unsecured furniture falling – Bookcases, cabinets, and water heaters can tip over, causing property damage and injury risk.
• Gas leaks and fires – If natural gas lines break, sparks from damaged wiring can ignite fires.
• Water and sewer line breaks – Underground utility connections can be disrupted, leading to flooding or contamination.

The severity of damage depends on the earthquake's magnitude, distance from the epicenter, and the construction of your home. In New Hampshire, many homes have basements and are built on frost-resistant foundations, which generally fare well in small quakes. However, older homes with unreinforced masonry foundations or chimneys are more at risk.

One critical concern is insurance. A standard homeowners insurance policy in New Hampshire does not cover earthquake damage. If you want financial protection, you must purchase separate earthquake insurance, either as an endorsement or a standalone policy. Given the low to moderate risk in the state, such coverage is optional for many homeowners, but it may be worth considering if you live in an older home or in an area with soft soils. Check with your insurance provider for options and costs.

How to Prepare Your Home

Even in a low-risk state, taking basic preparedness steps can reduce damage and improve safety during an earthquake. Here are concrete actions recommended by Ready.gov and FEMA:

• Secure large furniture – Anchor bookcases, tall cabinets, and shelves to wall studs with straps or brackets.
• Install latches on cabinets – Use childproof latches on kitchen and bathroom cabinets to prevent contents from spilling.
• Strap your water heater – Use metal straps to secure it to the wall, and install flexible gas lines to reduce fire risk.
• Repair cracks in foundations – Have a professional inspect and seal any existing cracks to keep them from widening during shaking.
• Brace your chimney – If you have a masonry chimney, consider adding reinforcement or retrofitting it to resist toppling.
• Keep breakables low – Store glassware and heavier items on lower shelves, away from beds and seating.
• Use flexible utility connectors – Install flexible pipes for gas and water to avoid breakage during ground movement.
• Create a family plan – Practice “Drop, Cover, and Hold On” and designate a meeting place outside the home.
• Build an emergency kit – Include water, food, flashlights, batteries, first aid supplies, and important documents.
• Know how to shut off utilities – Learn where your gas valve, water shutoff, and circuit breaker are, and keep tools nearby.

These steps are inexpensive and also protect against other hazards like severe storms, making them a smart investment for any homeowner.

Frequently Asked Questions

Are earthquakes common in New Hampshire?

Earthquakes are not common in New Hampshire, but they do occur occasionally. Most are very small and go unnoticed by residents. The state has experienced a few moderate quakes in its history, such as the 1940 Ossipee event, but damaging earthquakes are rare.

Could a damaging earthquake occur in New Hampshire?

Yes, a damaging earthquake could occur, though the probability is low. The same forces that create earthquakes elsewhere in the northeastern U.S. exist in New Hampshire, and scientists cannot predict exactly when or where quakes will happen. Even a moderate quake centered in the state could cause damage to vulnerable structures.

Does home insurance cover earthquake damage in New Hampshire?

No, standard homeowners insurance policies do not cover earthquake damage. You would need to purchase a separate earthquake insurance policy or an endorsement. Since New Hampshire's risk is level 2 of 5, not all homeowners opt for this coverage, but it's worth discussing with your insurance agent.

Official Resources

• New Hampshire Homeland Security and Emergency Management
• USGS Earthquake Hazards Program
• Ready.gov – Earthquakes
• FEMA Earthquake Safety