Big Sound That Shook Everyone Up

munk writes: Whether an explosion, an earthquake or a sonic boom, something loud and jarring occurred at 12:00 or 12:01. It was felt on the Mall, on Millmont Street, at Albermarle Square, and out River Road. Once before, Charlottesville had an earthquake that news sources insisted was a sonic boom for days, but this seemed like neither. We’re trying hard to find the source; it was short, loud, and local.

Update: Sonic boom? Military jet? Earthquake? Underground explosion? We’ve heard a lot of theories and no answers.

38 Responses to “Big Sound That Shook Everyone Up”

  • As of 12:00:04 EDT, the USGS reported no earthquakes in Virginia.

  • A call out to the airport, they didn’t hear anything out there.

    Two readers just confirmed that River Road heard the thing and “Carlton Ave / Carlton Rd. area Market Street [was] rocked.”

  • The police say it was a sonic boom from an aircraft.

    Kevin Cox

  • What’s important in all this: for some time we’re going to jump at just about everything like that and ther’ll probably be a whole lot more of them.

  • Maybe someone out there knows more about this than I do — Aren’t military aircraft (which I assume this was) not supposed to go supersonic over populated areas like Charlottesville?

    It shook the windows of my house (off 29N). All the neighbors went outside at once; a lot of people were quite shaken.

  • In the Greenbrier neighborhood we felt it more than we heard it — it shook the whole house. Assuming the worst, I phoned a friend who lives nearer to the Lake Anna facility, but they hadn’t heard anything.

    As reported earlier, the police claimed they *thought* it was a sonic boom.

  • How many, even if only briefly, had a thought of the “second wave” happening on the 22nd…today. My hand is up…

  • This was not a sonic boom. Over here on maywood, just off JPA, our entire house shook, as did our neighbors’. There was no discernible noise other than assorted rattles and groans from the house, though.

  • Why do you think it wasn’t a sonic boom?

  • Results here at UVA were silent with massive vibration. My room felt as if it were vibrating at about 25 cycles per second for about 2 – 3 seconds. I did not detect any sort of loud noise, though a low rumble was audiable.

    In responce to the questions about sonic booms, military aircraft are not supposed to go supersonic over population centers w/out very good reason. I find it unlikely that this was a sonic boom as such a phonomina tends to create a thunderclap type effect, and should not have any sort of effect which can be felt (felt, not heard) by humans. Whatever hit us did so with enough force to move the building I’m in.

  • Another area reporting–I live near Charlottesville High School and the boom made our floors and walls vibrate, our windows rattle, and our napping baby wake up.

    We assumed that it was a tree falling over, because that has happened before–down in the Meadowcreek Park which runs behind our house, an entire tree fell across the creek a couple years ago. The noise woke us up. So this time I went out looking from our deck for fallen oaks, but saw nothing.

  • We were walking at Darden Towe Park. To me, it sounded like an explosive “boom” but the earth moved very powerfully under my feet. It did NOT feel like a sonic boom. There was deep movement under the earth. I was barefoot on one of the walking trails. Never having experienced a quake, we figured it was a bomb or crashed airplane. SO relieved to find out it wasn’t…

    –Michael Sokolowski

  • My experience with sonic booms is that if one were to be this intense the jet would have to be quite near and quite low. I used to live near an AFB, they just don’t get that loud normally. if this were the case, we certainly would have been able to hear the sound of the jet following the initial boom. anybody hear a plane?

  • Back in 1998, when we had our last earthquake, WVIR and the police immediately declared it to be a sonic boom. I said, loudly, that they were all full of shit, and went about learning more about earthquakes. Come to find out a day or so later, of course, it was very much an earthquake. Most of us (as many people reported) know the difference between the ground shaking and a noise from the sky.

    In any case, my point may be worthless, given that the USGS still has no report of an earthquake.

  • In recent history (that is, the past few years), we’ve had two earthquakes here. I believe it was in 1998 that we had one centered in Free Union that registered 2.8. Then we had another one, in the past year I believe, centered someplace nearby. Fork Union, perhaps? It was an unusually deep quake, if memory serves. Now, in 1998, Central Virginia experienced five small quakes, all between .5 and 2.8. Most of those were not even felt; anything less than 2.5 isn’t generally noticed.

    Going back a little farther in history, we can look at UVa’s overview that goes back about 150 years. Here’s their description of the area:

    The Central Appalachian region is characterized by a moderate amount of low level earthquake activity. Because of the low seismic energy release, this region has received very little attention from earthquake seismologists. A study by Dr. G.A. Bollinger of Virginia Polytechnic Institute covering the period of l758 through l968, indicates a history of 9 earth tremors in the city of Charlottesville and Albemarle County during that period.

    They go on to list a handful of quakes, though they’re on the antequated Mercalli scale, so not as accessible to you and me.

    Here’s hoping that geology student at UVa gets on here and fills us in. One of you students grab an earthquake geek and get them to post, huh?

  • Aren’t stealth(TM) aircraft engines baffled for noise?

  • WVIR says that police are reporting it was a sonic boom. (Hardly news to all of us cvillenews-ers, but whatever.) This report is pretty much a verbatim repeat of WVIR’s inaccurate report of the 1998 earthquake, so I don’t put too much stock into it.

    BTW, I found the first (and only?) physical damage from this quake-like geological event. (How’s that for hedging?) A flourescent bulb fell from the ceiling in the stairs of my apartment building, smashing on the cement floor. How exciting.

  • Unless there’s something new afoot, both of our stealth aircraft, the B-2 and the F-117, are subsonic aircraft. But to answer your question, yes, they do employ noise reduction.

    This doesn’t sound like it was a sonic boom. Ive heard many, adn they sound like thunder. I don’t recall the ground ever shaking.

    Could be a new aircraft developed using alien technology. That would explain it. ;-)

  • For what it’s worth–it seems likely to me that the likelihood of a sonic boom has sharply increased lately. There must be military jets scrambling to and fro all the time now.

    Back on the evening of Sept. 11, my parents called me from Ohio to report that they had just heard and felt an incredible boom, as had all their neighbors. The local news began (irresponsibly) reporting the possibility of a plane down (even though all flights had been grounded). The news later reported that it had been a sonic boom, which made sense because they live near Wright-Patterson AFB, and jet activity was increased.

    There are no bases near Charlottesville, but it’s still believable that jets are flying over us all the time, isn’t it?

  • I heard no jet afterwards, and being privy to real sonic booms in the past, I can assure this was no sonic boom.

  • I was standing in Bodos when the boom occurred. It did sound something like a sonic boom… but then, any quasi-distant explosion would.

    What struck me the most, was the way that the ground shook. I’ve never experienced a sonic boom that did that.

    Everything went quiet for a few seconds.. and then everyone standing there began asking everyone else whether we should get out or not. The man that handed me my order was quietly chanting “That was a bad sound. A very bad sound,” over and over again. And yes, I immediately thought of the “rumor” that there was to be a second wave of terrorist attacks on the 22nd.

    I hope to find out for sure what it was. Right now, “Sonic boom” is simply the most convenient answer. If I see an earthquake report, or hear a statement from the air force, then I’ll be happy.

  • One word… Tunguska.

  • “tunguska” would actually make a fair amount of sense, if anyone could produce a rock. doesn’t really explain the sound though.


  • I can’t say I know how to read this data but all four of the 9/22 graphs here show something interesting at about 2 minutes after noon.

    It does not appear that this page will be available for long…

    -Morgan McLeod

  • I too was at Bodo’s and felt the boom. The room became completely silent for 10-15 seconds. Having grown up near an air force base it was clearly a sonic boom. First there are more military jets flying over our airspace then any time in recent history. Secondly having watched jets fly formations -when a boom hits it is suddenly and disapates quickly. Also about 5 to 10 years ago their was a similiar boom that was attributed to a new spy plane code named Aurora. It was cover by WINA.

    There is no way this was an earthquake. Yes they are not suppose to boom over population- People we are at war. When I was growing up we use to call that boom “the sound of freedom”.

  • To follow up on Morgan’s excellent link, see this image in particular:

    There’s definitely a big spike right at noon. Not that I have the slightest idea of how to interpret this graph.

  • from the website cited this was most interesting:

    These “skyquake” are a continuing phenomenon, with the most recent report over Orange County, CA coming on 20 July 1996. It is reported that the “quake” occurred around 3pm PST, fitting the “skyquake” pattern in the following respects:

    It occurred in a coastal area.

    Described as similar to an earthquake in some respects (rattling of loose objects, etc) but also like a boom (but no distinct double bang as far as is known).

    Severe enough to light up government and media switchboards, but no known damage.

    Not an earthquake (CalTech sensors saw nothing)

    Local military bases deny any knowledge.

    No known other source (eg explosion)

  • agreed. i heard word from a student at VCU that planes have been overhead a lot in the past few days. anyone know anything about this?

  • Anonymous wrote:

    Yes they are not suppose to boom over population- People we are at war. When I was growing up we use to call that boom “the sound of freedom”.

    I know the media likes the word, but is it really “war” before this country publicly names a specific enemy and launches an attack? I would say that we are most likely going to war with somebody, but nothing formal (as of this moment) has been declared by the U.S. against a specific group or nation. We are in the process of an overseas and domestic military buildup, but not at war.

  • we were at war December 8, 1941 even though we were in almost the same state we are today- at that point we had declared enemy Japan & Germany(now bin ladin network). And we were then in process of a buildup at various fronts. Make no mistake – a joint session of Congress, National Guard activiated, & no carrier groups in the harbor. The act of war is the buildup as well as the conflict.

    We have a declared enemy just not a place to attack them-yet. We may never have a formal declaration

  • Its suprising to see how many theories we all have here. I was asleep at noon, and bolted up out of bed so quickly that the initial “boom” was still happening, then I heard and felt the “rattle”. I immediatly thought it was a sonic boom, but went outside to make sure there wasnt a blown transformer or other explosion, all I saw was every one of my neighbors outside doing the same thing.

    The people here who say “I’ve heard sonic booms, and thats no sonic boom” are using false logic, every type of aircraft has its own “boom” sound, a space shuttle makes a different sound than an SR-71 which is different from the concorde etc. The sound is also affected by the speed of the aircraft, plus altitude, vehicle attitude and flight path, and weather or atmospheric conditions. The last verified boom we heard here was 5-7 years ago when a SR-71 decelerated over VA to arrive at an airshow in DC. This was verified by the USAF and I was outside when it happened, It sounded much like the boom we heard here, loud boom, deep rumble, and it shook the ground and windows. It was picked up by the USGS, as usually happens.

    The theory that for it to be that loud it would have to be “low or nearby” is totally false, if you took a plane to mach 1.1 at “low” altitude the aerodynamic pressures would damage the plane. These aircraft are engineered to fly at much higher altitudes. There are fighers that have broken the sound barrier extreemly low, but that is done to show off the vapor cone, and they usually just approach the sound barrier, not go past it. And as for close, when the space shuttle decelerates over the pacific ocean, it is heard hundreds of miles away all over California and the west coast.

    Having lived in L.A. and experienced a 6.5 earthquake and several smaller ones, I can tell you this was NO earthquake. Earthquakes have such low frequency you cannot hear them. Also, a sonic boom is a wave of highly pressurized gas, which is why the windows in our house rattle. If you were extreemly close to the aircraft it would shatter your windows, as the high pressure air outside tries to fill in the relativly low pressure in your house. An earthquake would shake everything, not just your windows.

    As for the military not being allowed to go supersonic over the US… think of it this way, the military can do whatever it decides it can do. There are several established “supersonic corridors” within the continental US that are for military and research use. Aside from that, there are reasons to go supersonic outside those corridors. An SR-71 leaks fuel thru gaps in its fuel tanks on takeoff, there is literally gas pouring out of it onto the runway. Infact, it must be in-air refuled first thing after takeoff because it has lost so much fuel already. Until it gets up to speed and altitude the metal doesnt expand enough to seal the leaks. Could you imagine flying an SR-71 from CA to VA without going supersonic? It would be a dangerous if not impossible task.

    Obiously nobody “knows” what it was but if I was a betting man I’d say it was an SR-71, a B1 bomber, or possibly an unknown aurora-ish classified aircraft.

    If the USAF authorized this as opposed to it being a mistake, it shows a lack of concern on their part for the general fear americans had about the reports of the 22nd being significant to the terrorists.

  • As a friend (former Air Force) pointed out to me Saturday, Langley is just “up the road”. He says that the AF and Air Force One uses air space over Charlottesville for practice. That could also explain planes over VCU.

  • If the source of the sound was in fact a supersonic aircraft travelling across the country, why was there not a long trail of boom reports? So far, I’ve not heard of any similar observations outside of the local area. Also, I did not *hear*, but rather felt the event. All sonic booms that I’ve previously experienced were followed by a sustained rumbling of engines post-boom. Perhaps it was a stealth aircraft designed to filter-out high-frequency components of the sound. Flight paths from the home bases of the F117 and B2 stealth aircraft, Holloman AFB, N.M. and Whiteman AFB, Mo, respectively, to Langley AFB in Hampton, would cross somewhere nearby. Those craft however are “high subsonic” and I’m not certain that they could create a sonic boom-like effect. In any case, the 12:02 seismic impulse recorded in Blacksburg seems inconsistent with sustained supersonic flight. Perhaps it was the sound of an Aurora-type vehicle decelerating… pretty amazing if it was. Then again, would (could) a black-op craft be flown during daytime to an airport near a highly-populated area (w/ no visual eyewitness reports)?

  • SR-71 Blackbirds have all been decommissioned Bub.

    Try Again…………..

  • SR-71 Blackbirds have all been decommissioned Bub.

    Try Again…………..

  • The speed of sound at any altitude is a function of air temperature. A decrease or increase in temperature results in a corresponding decrease or increase in sound speed. Under standard atmospheric conditions, air temperature decreases with increased altitude. For example, when sea-level temperature is 58 degrees Fahrenheit, the temperature at 30,000 feet drops to MINUS 49 degrees Fahrenheit. This temperature gradient helps bend the sound waves upward. Therefore, for a boom to reach the ground, the aircraft speed relative to the ground must be greater than the speed of sound at the ground. For example, the speed of sound at 30,000 feet is about 670 miles per hour, but an aircraft must travel at least 750 miles per hour for a boom to be heard on the ground. It could easily cross the country without a “carpet boom” dragging behind it. It must also decelerate and descend for landing or in-air refueling before crossing the atlantic. It is difficult for a pilot to know if he is going to boom as he slows and decends because of the many complex variables involved.

    Ground width of the boom exposure area is approximately one mile for each 1,000 feet of altitude. So an aircraft flying supersonic at 30,000 feet will create a lateral boom spread of about 30 miles. This means that we wouldnt hear reports from “all over the country” but rathar from a narrow path depending on altitude. This is why the space shuttle booms can be heard at great distance, since it comes in from a very high altitude indeed. Boom intensity is greatest directly under the flight path, progressively weakening with greater horizontal distance away from the aircraft flight track. This explains why some people here reported a large boom that shook their house, and some reported a slow rumble under their feet, with no loud noise at all. Other things like mountains, general weather conditions, etc. can affect the intensity at a given point.

    The reason you didnt hear jet engines after the boom is that the aircraft is both at a high altitude and VERY far away. If it was an SR-71 it could have been traveling as fast as Mach 3 (about 2100 statute MPH) and depending on its altitude and the boom delay it could have been as far as 50 miles away at the moment you heard the boom, and every 60 seconds after the boom is heard it travels another 35 miles farther away. To put this into perspective, on perfectly flat terrain (like the ocean) the line of sight to the horizon is only 20 miles, even less when terrain is in the way. So when you heard it, the plane wasnt even visible in the sky anymore.

    As for the SR-71 being decomissioned… it was in 1990. But in 1994, the Senate and House put $72.5 million into the FY1995 defense budget to refurbish and re-equip two SR-71s, one that had been stored but not flown by NASA and another that had been stored at the Skunk Works facility at Palmdale. The following year, they managed to add another $35 million to keep the work going, including refitting of an Edwards AFB hangar/headquarters for the Blackbirds and to allow the Air Force to retrain three flight crews, each consisting of a pilot and a reconnaissance operator who had logged pre-1990 SR-71 time. As work began on the FY97 defense budget the House National Security Committee, now operating under Republican leadership, took note of the fact that the Air Force had not put in a request for SR-71 funding. It is not unusual for one of the armed forces to deliberately not request money for some specific program, usually an older one that has lost some of its glamour, in the belief that proponents in Congress will add the necessary funding in what amounts to a gift. The comittee decided that while having a unique capability, the SR-71 program had in their view become too expensive. They decided to cease 1996 SR-71 operations, which then consisted of crew training and equipment test flying. The comittee wrote into its defense authorization plan a prohibition against any DOD operations of SR-71s in the fiscal year 1997. Several in the Armed Services Committee had been pleased with the timely and cost-effective reconstitution of a contingency force of manned, high-speed penetrating reconnaissance aircraft until penetrating unmanned aerial vehicles could be put into widespread use. Backstage maneuvering continued throughout the summer and early fall. When the final defense budget was finally sent to the White House for signature, the SR-71 had been kept alive. The budget included $39 million to provide for operation and maintenance of the two Blackbirds, along with procurement of spare parts and equipment.

    This was done partly in response to complaints that satellite imagery in the gulf war was “too old to be of use”. The SR-71 can collect highly detailed imagery from all of a region the size of Iraq in 20 minutes and deliver it directly to forces on the ground in about 10 more minutes. One of the wild theories as to why it was recomissioned is that the Aurora project was a total failure, consuming hundreds of millions of dollars and producing absolutly nothing, which explains why people in the DOD dont want anyone to know we spent so much on it.

    Anyway, I like the SR-71 a LOT, if you didnt already notice.

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