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According to dozens of posts on Facebook, a set of loud ground-shaking noises was heard last night in areas of eastern and northern Lebanon County, such as Avon, Myerstown, and Fredericksburg.
Although some commenters have speculated that an earthquake or tectonic shift was the cause, the USGS earthquakes dashboard shows no disturbances anywhere close to Pennsylvania. The Penn State managed Pennsylvania State Seismic Network shows a single seismic event last night, a 1.4 magnitude tremor west of Altoona.
From the reports, it’s tough to discern which correspond to the “event” and which may have been fireworks heard as part of New Year’s Eve celebration. The event itself appears to have occurred between 9:20pm and 9:30pm.
Most of the reports and discussion occurred on a Facebook post by Lebanon County Fire & Emergency Alert, which has since been deleted (this paragraph was updated at 4:30pm to reflect the deletion).
Some have speculated that the event was a meteor falling to the earth, a phenomenon sometimes called a fireball. Here is what the American Meteor Society has to say about the meteoric boom effect:
If a very bright fireball, usually greater than magnitude -8, penetrates to the stratosphere, below an altitude of about 50 km (30 miles), and explodes as a bolide, there is a chance that sonic booms may be heard on the ground below. This is more likely if the bolide occurs at an altitude angle of about 45 degrees or so for the observer, and is less likely if the bolide occurs overhead (although still possible) or near the horizon. Because sound travels quite slowly, at only about 20 km per minute, it will generally be 1.5 to 4 minutes after the visual explosion before any sonic boom can be heard. Observers who witness such spectacular events are encouraged to listen for a full 5 minutes after the fireball for potential sonic booms.
Some did report sightings of a blue flash preceding the noise, so the meteor theory seems plausible. If this were the case though, we might still expect video to emerge of the explosion moment, as captured in this 2015 video of a meteor exploding outside Pittsburgh:
No such video has been posted to social media yet of last night’s instance.
So, what else could it be?
It could have been a group setting off larger-than-normal fireworks.
It also could have been connected to the Sunoco pipeline system that runs through this part of the county. The Mariner East 2 pipeline reportedly went into service just this past Saturday, and the route does run squarely through the vicinity of last night’s event.
We have contacted Sunoco to see whether they are aware of any pipeline-related disturbances that may have occurred last night.
Do you have another theory of what happened? Video perhaps? Get in touch: Drop it in the comments or email us at firstname.lastname@example.org.
Update 12:15pm: We have a new theory presented by Fredericksburg-based scientist Clint LeRoy, who drew on an insight he had as a HAM radio operator that radio and sound waves travel further when the air is dense and moist. With last night’s atmosphere being especially moist but mostly cloudless, it could have provided the perfect conditions for sound waves to travel far distances. LeRoy has explained this theory in greater detail in a comment below as well as a post to his Facebook profile. “This was not an earthquake. What occurred is like the ‘Perfect Storm’ with atmospheric conditions pushing the noise to greater and greater distances,” said LeRoy in the post.
While LebTown has not independently confirmed this explanation of events, it could provide a generalized explanation of how people across Pennsylvania heard fireworks and fireworks tests over unusual distances and in unusual resonance due to the atmospheric conditions.
What do you think? Remember… The truth is out there.
Update 6:15pm: The National Weather Service in State College confirmed this afternoon on Twitter that lightning strikes were observed in areas of southeastern Pennsylvania from Franklin County eastward.
The NWS confirmed that last night’s moist and dense air could have caused these sounds to travel further than they normally would.
Penn State meteorologist Steve Seman shared with us a map depicting the locations of the record strikes last night. Although the map shows strikes, none appear that close to the areas of Lebanon County where reports of the event were most widespread.
The Storm Team at WGAL 8, for one, has endorsed this explanation of events, posting this Facebook message with a recording of the station’s doppler imagery from that same period.
While this explanation certainly seems plausible, we have no actual confirmation that this was the cause of the noise. However it seems like the best available theory at this time.
It has also come to our attention that WSBT-22 in Indiana reported on a very similar sounding disturbance that occurred in that region on Sunday night. We have no reason to believe that this “loud boom” event was linked to the Monday night event in Lebanon County, but the similarity is indeed striking.
Another theory we’ve seen mentioned a few times is that someone was shooting tannerite causing it to explode. Tannerite-caused loud booms have been documented elsewhere in the country, such as a few years ago in Chautauqua County, New York and this past January in Michigan. However we have not seen any contextual evidence that supports this theory (if you have, please let us know).
Is there something else we’re missing? Have you seen any other official organizations comment on the noise? As always, you can reach us through the comments or by shooting us an email.
We heard it at the 9:30pm time frame and again just after midnight. Both times our house shook.
Heard and felt in the Hummelstown/Hershey area also. Since it was raining….wrote it off as thunder. But IT WAS unusally loud.. not fireworks sounding at all
The same event happened at 6:30 pm in warsaw indiana yesterday it was covered on WSBT-22 news google it and watch it! Thats 596 mile away from lebanon pa! There is no way this was fireworks! They ruled out a frost quake and said since no lights were reported it in unlikely to be meteor related.
I heard it. I felt it ! Heard a loud BOOM , right after we felt our house shake and rattled things on shelves . This was NOT FIRE WORKS IT WAS POURING DOWN RAINING AND WHERE I LIVE NO FIRE WORKS NEARBY. TELL TRUTH SOMEONE HAS TO KNO WHAT THIS WAS. Maybe the prophecy of the end times is coming in motion , this was heard and felt to far away st same TIME TO BE FIRE WORKS !!!! DONT BE FOOLISH , this was something that is supposed to WAKE US UP !
We heard it and felt it here in Berks Co. in the Wernersville area. My husband and I both looked at each other and asked what the H#!》that was?
It was not fireworks it was loud like I never heard before and the house shook I live in Myerstown
Are you sure Jim wasn’t snoring?
I was asleep.
It was not just a noise. Our whole house shook. We live near Stoevers Dam. So I doubt it was from fireworks.
It was my girlfriend falling from heaven. Now someone find her and bring her to me
Martinsburg wv… happened here too. It was super scary.
I just checked and my wireless doorbell detected motion at 9:26 pm on New Year’s Eve. Video doesn’t show anything unusual.
I live on the western slope of Colorado and several people heard it here. I think it was nationwide. Cause still unknown.
I dont think this fireworks explanation would explain the sound being heard in Counties which are 50 miles away.
Granted I’m not a scientist, nor a meteorologist.
It was heard and felt in berks county and York county as well
We felt it in Stricklerstown, on the outskirts of Newmanstown. They also heard and felt it in Schoeneck, Bernville, Elizabethtown, Womelsdorf, Wernersville, Robesonia, Lebanon and Palmyra.
December 31 2018 – Lebanon County Loud Noise – heard near 8 45 PM
New Year’s eve in Lebanon County a loud explosion was heard across the entire County and beyond. As a scientist I too have a direct connection with the USGS, but upon hearing this sound from my home I looked up the USGS service website covering Lebanon County and found nothing, I know that actual reporting takes just 2 tenths of one second to be placed on the website with accuracy down to less than ¼ mile. This was not an earthquake. What occurred is like the ‘Perfect Storm’ with atmospheric conditions pushing the noise to greater and greater distances.
I am an Extra Class HAM Radio operator as well; this means I understand the conditions the sky can create to promote or reduce radio transmissions across the sky at any time, for best outcomes. In this case I can explain the situation that occurred and why so many people heard the noise even past Lebanon County.
In weather systems there is always a trailing edge of storm that seems to be dragged along behind the major storm system. This trailing edge is nothing but the barrier between the low pressure air weather system and the incoming Dry air mass or High pressure mass moving into the area. Many times you will see no clouds and the rain will continue to fall unabated. This condition is due to excessive moisture conditions when the edge of the trailing low pressure system is being pushed along by the incoming high pressure system trailing behind. This cloudless area yet high rain content is the excessive moisture window where the boom was heard last night. SOUND travels greatest distances when moisture exists, look at the Oceans. Whales communicate over >1,000 miles with their sonar because sound travels through the water at pressures of >768 times the density of air. Now set off an explosion in a high moisture content atmosphere like last evening, and where the moisture is at its highest is where the sound will travel.
A test firing of the 12 midnight Fire Works to be set off my Myerstown community is what caused this disruption. Atmospheric conditions in perfect alignment allowed the sound to travel such great distances.
By the 11:45 PM window of the wall of High pressure system clearing out the wet weather is when all fancy NYE balls dropped and by that time all means to have sound travel normally returned.
Possibly Tannerite. This happened in Lancaster county when I lived there
Agree with Tracy, could Possibly have been Tannerite. This occurred in the Ephrata area about a year ago maybe little less and it was felt for miles away and shook homes and was a mystery until they found out someone had been playing with tannerite.
IT WAS DEFINITELY NOT FIREWORKS!!!!!
We live in the Avon area just behind the Lebanon County Career and Technology School. My wife had just fallen asleep while I was watching football when we felt the shock wave and she came running out of the bedroom. The feeling was like a huge thud and we could feel the house shake on its foundation. Most of my neighbors were then outside looking around as I was trying to figure out what had just happened. There was no noticeable flash in the sky to indicate lightning or anything like that. I could not believe how powerful and sudden the shock was. I thought that maybe something on the railroad had exploded but there was no indication of fire or anything else like that. When I read that people in Jonestown and Myerstown felt it also, it makes me wonder just what happened and where.
MY MOTHER-IN-LAW TRIPPED AND FELL
HER NAME IS FAYE FAHLER AND LIVES IN JONESTOWN,PA.
We heard it…it was not fireworks. It shook our windows. We live on race street in Myerstown. It was definitely an exploding sound and feel.
Yes, we heard and felt it as well! We live in Arbor Gate in Myerstown…NOT a firework!
I agree. That was NOT fireworks. It sounded more like thunder. But it shook our house. Sounded like something had dropped on the roof
It shook our house too not fireworks