Earthquakes risk in Pennsylvania

Earthquakes in Pennsylvania: Low Risk, Not Zero

Pennsylvania is not located near the boundaries of major tectonic plates, and the state is rated level 1 on the National Risk Index for earthquakes. This means the risk of experiencing a damaging earthquake is very low compared with the rest of the United States. However, earthquakes are not impossible in the Keystone State.

Most recorded earthquakes in Pennsylvania are small and go unnoticed. The areas with the highest likelihood of experiencing felt tremors are in the southeastern part of the state, including the Lancaster and Philadelphia regions, and in the central Pennsylvania area near the Susquehanna River. These events are typically linked to ancient fault lines deep within the earth's crust, not to the large plate boundary faults that cause major earthquakes in California or Alaska.

Earthquakes in Pennsylvania do not follow any seasonal pattern. They can occur at any time of day or night. Unlike weather-related disasters, there is no warning before an earthquake. For this reason, even in low-risk states, it is wise to know what to do if the ground starts shaking.

How It Affects Homes

Because Pennsylvania's earthquake risk is low, most homes in the state have never experienced any kind of earthquake damage. Yet a moderate quake centered near a populated area could cause cracking in masonry, foundation shifts, broken windows, or toppled items. Chimneys are particularly vulnerable to shaking because they are tall and heavy, and can collapse if the masonry is already weakened.

In older Pennsylvania homes, unbraced foundations and load-bearing stone or brick walls can be more prone to damage. Homes built before modern seismic codes may not have the same resistance to earth movements as newer structures. Even in a low-risk state, a home with unreinforced brick or cinder-block construction could sustain more damage.

Insurance is another important consideration. Standard homeowners insurance policies in Pennsylvania typically exclude earthquake damage. If an earthquake were to cause a fire, most policies would cover the fire damage, but the earthquake damage itself would not be covered. Homeowners who want protection need to purchase a separate earthquake insurance policy, usually offered as an endorsement by private insurers. Because the risk is low, the cost is often relatively affordable, but it is still an extra expense.

How to Prepare Your Home

Even though the risk is low, taking a few minutes to prepare can reduce potential damage and help keep your family safe. The following steps are recommended by FEMA and Ready.gov for earthquake preparedness:

• Secure heavy furniture. Anchor bookshelves, cabinets, televisions, and tall dressers to wall studs using brackets or straps.
• Fasten water heater. Strap your water heater to the wall to prevent it from tipping over and rupturing gas lines or water connections.
• Check your foundation. If your home has a crawl space, inspect the foundation for existing cracks or weaknesses. Consult a structural engineer if you have concerns.
• Store breakables safely. Keep heavy or fragile items on lower shelves, and use museum putty or similar compounds for glassware and collectibles.
• Know how to shut off utilities. Learn how to turn off the gas and water at the main valves. If you smell gas after an earthquake, shut the valve and call your utility company.
• Make a family plan. Agree on a spot to meet outside after a quake, and practice "Drop, Cover, and Hold On" with your family.
• Prepare an emergency kit. Include water, non-perishable food, flashlights, batteries, a first aid kit, and medication.
• Consider earthquake insurance. Evaluate your financial ability to repair damage, and talk to your insurance agent about adding earthquake coverage.

Frequently Asked Questions

Are earthquakes common in Pennsylvania?

No. Pennsylvania experiences very few earthquakes each year, and most are so small that they are not felt by residents. The state has a history of occasional minor tremors, but damaging earthquakes are extremely rare. According to the USGS, the probability of a strong earthquake occurring in Pennsylvania is among the lowest in the country.

Can coal mining or drilling cause earthquakes in Pennsylvania?

Small tremors in mining regions can sometimes be caused by the collapse of abandoned mine workings, but these events are usually very localized and minor. The USGS notes that most induced earthquakes are linked to deep wastewater injection wells, which are not a major activity in Pennsylvania. Overall, the risk from human-induced earthquakes in Pennsylvania is very low.

Should I buy earthquake insurance in Pennsylvania?

That depends on your personal risk tolerance and the value of your home. Since Pennsylvania is in a low-risk zone, earthquake insurance is not a top priority for most homeowners. However, if you live in an older house with masonry construction or on a steep slope, or if you want total financial protection against any major disaster, adding a small earthquake endorsement to your policy might give you peace of mind. Talk to your insurer about the cost and what it covers.

Official Resources

• Pennsylvania Emergency Management Agency (PEMA)
• USGS Earthquake Hazards Program
• Ready.gov – Earthquakes
• FEMA Earthquake Safety