What are aftershocks and should you prep for them in NY after Friday’s earthquake?

After a 4.8-magnitude earthquake centered northeast of Lebanon, New Jersey rattled parts of New York Friday morning, it left many wondering about the possibility of aftershocks.

No “life-threatening situations" or damage has been reported in New York so far as a result of the quake, Gov. Kathy Hochul said during a news conference Friday, but there is a possibility for aftershocks.

Hours after the governor’s briefing, a 4.0 aftershock hit the New York City area Friday evening.

Here's what to know about aftershocks and if there will be any more in New York.

What is an aftershock?

Aftershocks are small earthquakes that occur in the days, months or years in the general area following an earthquake, USA TODAY reported. Aftershocks are minor readjustments made near the faults, or areas in the Earth’s surface where stress occurs during an earthquake.

Aftershocks can occur in the thousands and can still be damaging or deadly. In earthquakes, the “mainshock” is the largest activity felt during an earthquake.

Will there be any more aftershocks from Friday's earthquake?

Possibly.

There can be aftershocks in the coming days and there is a small chance of a follow-up earthquake of a similar magnitude, the USGS said in a press conference Friday.

Aftershocks in the 3-4.8 magnitude range can be expected on average, according to the USGS, but some aftershock sequences are more energetic than others.

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How many aftershocks can you expect after an earthquake?

Globally, the probability one earthquake will be followed by a large earthquake within 3 days is somewhere just over 6%, according to USGS. That means whenever there's an earthquake, there's about a 94% chance that it wasn't a foreshock and there won't be any more quakes linked to it.

With Friday's earthquake, the USGS says there are low but not zero odds of another earthquake greater than a 5 magnitude occurring over the coming year. Additionally, it is "more likely than not" that at least one aftershock greater than a 3 magnitude will occur over the next year.

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What to do if there are aftershocks

If there are any aftershocks, Hochul told New Yorkers to drop to the floor, cover your neck and hold on to something sturdy.

Hochul also advised New Yorkers to take caution near any damaged buildings, inspect your homes for damage and to leave your home if you hear any shifting or unusual noises.

Reporting from USA TODAY is included in this report.

Emily Barnes is the New York State Team consumer advocate reporter for the USA TODAY Network. Contact Barnes at ebarnes@gannett.com or on Twitter @byemilybarnes.

This article originally appeared on Rochester Democrat and Chronicle: What are aftershocks and will they hit NY after Friday’s earthquake?