So since I live near epicenter, there's one thing that changed geographically very recently. Nearby round valley reservoir was being worked on for years, last fall they got the authorization to pump it back to full and it was told it might take years. Rainy asf winter though so it's pumped back almost full from already 66% to 92% now. I'm wondering if billions of gallons of water getting added nearby affected pressure on the fault. Here's today's operations data (we just had 3.5in of rain past couple days too): https://www.njwsa.org/uploads/1/0/8/0/108064771/data.pdf
EDIT: just had another aftershock right after posting this. Felt the 2.0 a couple hours ago too
It's possible. Seismicity has been associated with reservoirs[1] (the most well known is probably an earthquake in Egypt following the construction of the Aswan High Dam) and even rainfall[2]. There are both potential triggers from the increase in the stress on the fault, as you state, due to the weight of the water; and (probably more important) the increase in pore fluid pressure along the fault.
It's a bit complicated, because the increase in stress on the fault from the weight of the reservoir can actually be primarily an increase in normal stress, i.e. an increase in the clamping force preventing the fault from slipping (i.e. the crust on either side of the fault sliding, i.e. the earthquake), so the weight of the reservoir can actually impede, rather than promote, seismicity. However if the geometry of the system is just right such that the increase in shear stress from the weight of the reservoir can increase on the fault, then the reservoir could really trigger the earthquake. Typically, though, the increase in pore fluid pressure is the most likely trigger as it's not geometry dependent--pumping a fracture with fluids will always promote failure. This is what happens with the seismicity associated with natural gas fracking and subsequent wastewater fluid injection.
The thing that is hard to grapple with all of this is that changes in stress and fluid pressure on the fault are really, really small compared with the ambient stress and fluid pressure. These are tiny changes, but there is good reason to believe that many faults, especially those in seismically active areas, are very close to frictional failure (i.e., slipping and producing an earthquake) all the time. So therefore little things can perturb the system. However, it's worth keeping in mind that most of these small changes slightly increase or decrease the time to failure (as the primary loading that is causing the stress on the fault is probably continually happening at very low rates), rather than being the ultimate cause of the earthquake.
Good shit, this is the kind of answer I hoped for posting on HN. I don't know too much about earthquake seismology, but I am curious and know where to pull random data.
So I thought, if the ground is moving the aquifer levels might change (no clue whether they would go up or down). I just pulled the ground water levels for Readington Township's well (in which whitehouse station is a place). Sure enough can clearly see when the earthquake hit: https://waterdata.usgs.gov/monitoring-location/4035170744525...
So is this expected? Is this a thing that normally happens with earthquakes?
EDIT: Japan paper was cool https://sci-hub.ru/https://www.sciencedirect.com/science/art... apparently they measure increased seismicity at times of high inflow. Also just had a big aftershock approx 22:00UTC. sounded like a bomb (I am in whitehouse station now)
OP is saying that much rain got into a reservoir that sits on top of an ancient volcanic caldera and has no rivers flowing into? Unexpectedly? and they didn’t think to stop pumping water in from the South Branch or release some water?
It's not at full capacity yet, they are pumping into it daily (around 200 million gallons) until it is. Only spruce run reservoir upstream of it fills naturally (and is spilling currently).
Operations data for the reservoir updates every morning during workdays, so we'll know Monday if they paused pumping into it after the quakes, I don't have any better than daily numbers for it. Letting the water down isn't an option, most of the downstream gauges on the south branch were just at or near flood stage. River gauges available here: https://water.weather.gov/ahps2/index.php?wfo=phi
Does anyone know if there's a real-time feed of Earthquakes somewhere? The USGS website doesn't post the Earthquakes until 10-15 minutes after it's over - which nullifies any type of automated warning for our data centers.
I felt a moderate earthquake here in Yokohama a few days ago. I had my phone with me, so I clicked my bookmark for that page and, before the shaking stopped, could see that it was a magnitude 6 with epicenter offshore from Fukushima--nothing to worry about. A minute or so later the permanent record of the quake was online:
My guess is that earthquakes powerful enough to cause a head crash are powerful enough for widespread destruction anyway, but I’m no expert. I did some quick searches for hard drives damaged by earthquake, and the only results I got were scenarios where the hard drives or the whole rack got knocked over by the earthquake and hit the floor.
Felt that very strongly in southern Westchester county NY. Not like the 2011 earthquake I felt in NYC, which was kind of slow and made the building I was in sway violently; this was more like the vibrations from a huge truck passing nearby, but more intense. Loud and very unpleasant, about 15 seconds duration. Did not like that at all, am now inspecting all our services like gas and water for disruption, checking for cracks and so on.
There actually was a large truck coming down my block in Brooklyn at the same time it started and it took me a second to realize that no, it actually was an earthquake.
And I definitely agree, the 2011 one was more of a sway, this felt like a rumble.
Funny you say that! I live in NJ now and felt the quake today. I just brushed it away as a truck passing by (I grew up in Brooklyn.) In NYC, it is so common for large trucks, major construction, pile drivers, subways running under the building, bad roads causing trucks to shake, etc...that I am just used to this.
I have not yet gotten accustomed to the stillness of suburbs despite being here for years now. (Side note: In NYC you can also get stillness and quiet, usually by going upwards into skyscrapers)
I was explaining the same to my wife. I think the last one was in D.C. and it felt the room was spinning slightly. Today was quite a different experience and truly scary for a moment as it started to ramp up and seemed like it wouldn't stop getting more intense.
As an easterner who lived in California for many years, the breathless news coverage of a tiny thunderstorm in CA which had a bit of lightning provoked a bit of a chuckle. The report was accompanied with statistics about how rarely lightning injured people and there was no real cause for concern.
Totally! The company I work for in Los Angeles gave a people a work from home day because it was raining. You can't be expected to drive to work in the rain? Not after COVID apparently.
I'm aware that Atlantic and mid-American quakes are felt over a much wider area than Left-coast temblors, because of the more-intact, less-fractured, largely limestone and granitic foundation bedrock (as opposed to a largely fractured sedimentary basement along the Pacific seaboard). But is the actual shaking intensity greater? AFAIU that's mostly affected by factors such as ground liquifaction, total ground water, and the like, which tend to be fairly strongly localised in effect. E.g., you can find seismic hazard maps of the SF Bay Area which show high-risk regions, largely on fill, reclaimed marsh, and sand dunes (e.g., the Marina, Financial District, SOMA, Sunset and Richmond districts of San Francisco), as opposed to bedrock (Twin Peaks, Potrero Hill). The former all amplify ground movement, the latter tend to shake far less.
River bottom land and estuaries on the East Coast would similarly show higher seismic motion, but I'm not sure this carries over for the region as a whole.
Plus the main aqua duct that supplies several million people is old and fragile. A simple earthquake could possibly turn into a Flint, Michigan level disaster.
Ha, I'm glad you capitalized on what was a great opportunity for a bit of inter-coastal banter. I'm only sorry my response was delayed. Perhaps we can reconcile our feelings at a holistic soul-healing retreat :)
>>> determined from the logarithm of the amplitude of waves recorded by seismographs. Adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake[1].
So unless people in the East have seismographs located farther underground with scientists staffing them really deep underground -for reasons beyond me- "Shallow depth" is irrelevant.
Also, there's no such thing as a "feels like X magnitude" earthquake [2]
>"Feels like" is measured on seismic intensity scales such as the Mercalli scale. These measure the peak acceleration or velocity at a given point, or the damage done by the earthquake. Intensity is influenced by many things, such as the depth of the earthquake, the distance to the ruptured section of the fault, and the local surface material.
Are you intentionally being pedantic? The point doesn't have anything to do with whether decimals are used or if conversions are direct. The point is that a 4.8 earthquake can feel different given numerous factors. The Mercalli scale attempts to capture the surface-level disruption, rather than the inherent force at the site of the quake as the Richter scale does.
Depth IS relevant to how an earthquake feels (as opposed to your assertion it isn't)--even the usgs publishes depth information. If you go back to the stack overflow link you posted, you can clearly see that a lower magnitude earthquake can be much more damaging.
The point is, richter measurement doesn't tell the whole story, and yes, you could say that a 4.8 would feel like a 6.0, even if we don't have a good way beyond the mercalli scale of discussing that. That's because the original output energy is only partially relevant to how someone experiences a seismic event.
tl;dr: your pedantic assertion that there's no conversion between the two is correct. your assertion that depth doesn't matter for feeling quakes is incorrect.
Yes, the Roman geologists did not use decimals but fractions. "S···· or S∷ | Dextans, dextantis or decunx, decuncis" would be the equivalent of .8 since they used "a duodecimal rather than a decimal system for fractions."
That was eerie! I felt my apartment building start to rock and sway as the walls were creaking. Not something I’m used to as a NY native, and not something I loved to experience 20+ floors above the ground.
On the 38th floor in Hell's Kitchen, I felt my chair and desk shake. It was like 10 seconds long.
One of my neighbours often close their doors with force which causes the wall to vibrate. Then I noticed things not attached to the walls also were shaking and understood it's an earthquake. I also noticed lots of birds flying near the Hudson River. I have never thought I would feel an earthquake here.
I also searched Google to see if there's an earthquake, and at 10:23am nothing was showing up. I remember a year ago Google used to ask "Have you felt your building start shaking", and nothing this time.
I was at a coffee shop in Astoria and it sounded like the subway running under. My first thought was that there is no line under this street (been living here forever). Then I thought maybe a jet liner flew over too close. But then judging by other people's reaction, I realized that this was an earthquake. I had no idea that you can hear earthquakes...
I was in the one in Seattle around 2000 on the 5th floor of a building, and I distinctly remember walking down the hall with the building swaying like a boat in a storm, wondering when the whole thing was just going to snap and crumble into a pile of rubble. Luckily it turns out they make modern buildings not do that. I've been back to that building and they still have cracks in the stairwell from it, though.
I experienced a 3.8 (I think) in Dallas some years ago, 30 stories up. It was likely caused by oil drilling action in the area, as Texas is not an earthquake zone if I remember correctly. It was not fun, no dampers in that building.
If any west-coasters are confused as to how this is news: the Northeast is sort of geologically unusual for the US in that we have almost no surprising, sudden weather thingies.
No tornados, mild thunderstorm, occasional hurricanes (but they are usually weakened a bit compared to, like, Florida by the time they get up here and they’ve spent a long time going up the coast so they tend to be well tracked by forecasters), some flooding but not much, and no earthquakes. Our bad weather events are usually blizzards, which you can see coming and which take a while to accumulate.
We’re right in the middle of the North American plate and the area is covered in gentle old hills and mountains.
So, we’re all just not used to the planet surprising us!
Also, earthquakes on the east coast travel further, and are more likely to damage structures than earthquakes of the same magnitude on the west coast[0]. That's due to underlying geological differences.
The magnitude is one immediately-available measure of the strength of an earthquake, but it's not the only measurement that's relevant to determining the size or impact of an earthquake. Depth, duration, location - there are many other measurable (and also immeasurable) factors which parameterize a seismic event.
I cannot speak for California, but in PNW there is even less “surprising, sudden weather thingies.”
Rain is not pouring, unlike on east coast (speaking from my expeirences in both NYC and Atlanta), it is just drizzling at a very low rate. It doesnt thunderstorm. I’ve heard thunder iirc only 2-3 times in my 7 years living there. No tornados or tsunamis. No massive blizzards out of nowhere. I felt this earthquake in NYC today myself, and I remember having a similarly strong eathquake in Seattle only a couple of times.
I have no idea where this “west coast and its sudden weather thingies” take comes from (again, I cannot speak for California), but it runs counter to everything I’ve personally experienced.
I have lived in California for something like 33 of my 36 years. I have actually felt a grand total of 3 earthquakes in my entire life. Even out here, quakes big enough to shift the wall decorations across a large portion of the state are vanishingly rare.
Uh... This is incorrect, and probably largely dependent on where exactly you live. Just go look at an earthquake swarm map of CA. Near the fault in Los Angeles have been dozens if not more of small/midsized/large quakes that could produce the effects you're talking about. I had one in my office just the other week that freaked everyone out.
I'm not saying there aren't earthquakes. I'm saying actually feeling/noticing them is extremely rare in my experience. Maybe I have just lived in exactly the right places over the years. Probably many happened when I was doing something that masked them, but nonetheless in over 30 years I have noticed just a few quakes, and only one was significant enough to leave any evidence in the form of moved objects.
There actually are tornados in the PNW. Both Washington and Oregon get about 1.7 per year. Here are maps of the tornados here since 1950 for Washington [1] and Oregon [2].
For Washington, in the 134 tornados since 1950 there were 6 fatalities, 303 direct injuries, and $31 million in damages. However most of that was from a single bad year, 1972, which had 4 tornados and all 6 of those fatalities, along with 301 of the 303 injuries. $25 million of the damages were from that year, too.
For Oregon it was 130 tornados since 1950, with 0 fatalities and 5 injuries. $32 million in damages. Like Washington most of the damage came from one year, 1968, with $25 million in damages.
Even though they are rare it turns out that we do have a functioning tornado warning system here. I found this out a few years when my iPhone started blaring a very loud alarm--louder than anything I'd ever heard from it before.
I've definitely seen a few "pouring rainstorms" this year where I'm at in the PNW. If you live in the Seattle area you're actually in the rain shadow of the Olympics, but when you get to about Mountlake Terrace to just south of Everett you're in a convergence zone and get all the weather that diverted around the northern half of the Olympics, so you can get a crazy amount of water there. I've also seen a LOT of rain just touring the Olympic coast(The Hoh rainforest is the wettest forest in the US), and also out on the San Juan islands and in the Bellingham area.
I've also been day hiking after work and gotten more than a few heavy rains. One of which almost gave me hypothermia because it snuck up on me while I was in the woods on top of something during one of those drizzles you're referring to.
House I'm renovating here in the northeast had the concrete in the basement poured yesterday... Going to head over there to see if any weirdness occurred
I had never been anywhere near a hurricane in my life before I moved to NYC. I thought that was just something you worried about in the Caribbean or occasionally Florida.
Yeah, our reaction to this here is reminding me of what happens when Oregon or Atlanta gets an inch of snow. An earthquake (that is felt) is just not something that we experience often.
I remember when Atlanta got 2" and people were literally abandoning their cars on highways [1], whereas in the northeast people are out driving in blizzards.
I think you’re drawing the wrong conclusion from the post. There was no suggestion of tornadoes on the West Coast. It was a discussion of relatively isolated meteorological phenomena in the northeast corridor.
While not part of Tornado Alley, the west coast does get tornadoes. There was at least one when I lived there, and I think I heard about another within the past year (maybe two). The one when I lived there actually started as a waterspout and came across the beach near Santa Monica to be reclassified as a tornado.
I'm not sure how this thread got off on this tangent but I don't think there was ever any attempt to comment on whether there are or are not tornadoes on the west coast. The discussion was the lack of extreme events typical of the northeast.
It's more about the details left out really. I lived in LA area for ~5 years, and 1 tornado. In one Tornado Alley storm system, you can get multiple twisters. There's of course more than one storm system per season. It's also just weird knowing that for a tornado to hit places like Santa Monica and the knowledge that tornadoes usually travel southwest to northeast, and that there is no more land west of Santa Monica, that they are going to form as waterspouts. That's just unusual for typical experience for Tornado Alley folks.
Just another example of how one person's typical experience with storms can still be unusual when experience some place else.
Sure, my original comment was very ambiguous about what I've just posted, but that's how the tangent worked in my mind.
We had some allright thunderstorms in MA, but I lived briefly in the Midwest and—they have these thunderstorms that are still scary even when you are inside. It is bizarre.
i live in dallas, about 10 years ago there was a small tornado skipping up and down about 3 miles north of me (they typically move SW to NE). I got in the car to "chase" it and made it to the end of my street. It was so ominous looking I turned around and went back home.
Some people misuse the term to mean "a blizzard affecting New England and/or the Northeast", but it actually specifically refers to a storm that's been pushed inland by sea winds coming from the northeast, off the Atlantic Ocean. That specific pattern results in a particularly cold and brutal storm.
Nor'easters are technically cyclones, just like hurricanes, and the two are very similar in many regards. The difference is that a Nor'easter forms further north, in cold water, and it is actually strengthened by cold air, whereas hurricanes form further south and are diminished in strength as they cool off.
Weather nerds will get very confused by ‘a cold hurricane’ since hurricanes are tropical cyclones and tropical cyclones have a warm core by definition.
…but they’ll be fine with a ‘a big cold cyclone’ I guess ;)
> Weather nerds will get very confused by ‘a cold hurricane’ since hurricanes are tropical cyclones and tropical cyclones have a warm core by definition.
Well, it's literally true: a hurricane is a tropical cyclone, and a nor'easter is an extratropical cyclone. A nor'easter is literally the "cold" counterpart of a hurricane!
It’s just a hurricane in the winter, no biggie. We would enjoy the snow and check out the surf (from a safe distance). I think you aren’t officially supposed to suggest the latter though.
I mean, it really isn't a huge deal, but the nor'easter that just came across us here in southern maine left about 350k people without power in a state of 1.6 million people.
its a lot of warm moisture that comes up the coast from the southeast and slams into cold air from canada and can drop a lot of snow/wind. It can cause bad storms in the ocean and high seas.
Eh, there are plenty of areas of the northeast that are affected much differently by these events than where you are. For example, Vermont has had multiple catastrophic floods in memory, including last summer and Hurricane Irene. Mountainous and coastal areas magnify these systems, the lowlands and developed megalopolis region may be truer to your claims.
The thought process was: I know earthquakes aren’t really weather, so I’ll tack on “thingies” to make it clear that I’m making up some new more generalized term.
The point was to group all the… I dunno, whatever, surprising attacks by the planet into one thing. I can’t think of a real term for this, I think there might not be one, I guess I could call it something like “weather or geological surprises” but that’s just dull.
Natural phenomena, extending beyond what's strictly weather, often get lumped into "meteorology", including earthquakes, tsunamis, and volcanoes. One fairly well-known case is the Japan Meteorological Agency (JMA), whose remit includes not just weather by hydrology, seismology, and volcanology.
Generally: concerns of an extra-human, non-biological origin. E.g., JMA doesn't address pandemics.
It just illustrates how people in the NE think about natural disasters. Basically any big natural event is weather-related.
When the 2011 Virginia quake happened, I was somewhere in the Boston area sitting in my parked car, and at first I thought it was a strong wind rocking my car side-to-side. It took a few seconds for me to realize the shaking wasn't a "weather thing"
I distinctly remember the first time I created a Twitter account (& probably became aware of Twitter being a thing) was the day when a similar earthquake was felt in NYC back in 2011...
I remember this earth quake! I missed it lol. I happened to be driving and we got out of the car to see a tv telling us how we got hit with an earth quake and my friend and I looking at one another like "what did we miss". This time I happened to be on the second floor of a small office building. I was about to run out of the building if it started to get worse I wasn't sure it wasn't the building having an issue.
I worked in northern Virginia at the time, fairly close to the epicenter.
Our office building shook violently. A poor woman I worked with was quite panicked, dove under her desk... and admonished me afterward for staying calm?
Earthquake waves have several propagation speeds, because there are different types of waves. The fastest is called the P-wave, which is a compressional (longitudinal) wave, similar to a sound wave, with a velocity of ~5-8 km/s for typical continental bedrock. The second fastest is the S-wave, or shear wave, which is about 65% of the P-wave speed. These waves produce relatively little displacement at the surface (except for close to the epicenter of large earthquakes) but are important seismologically. Then, there are the surface waves, which are caused by the interaction of the S-waves with the surface (in a way that I don't 100% understand). These travel about 90% of the S-wave speed, but they have the biggest displacements at the surface and therefore are the main ones that you feel and that cause damage.
The surface wave displacements also get amplified in wet or loose soil, so the ground shaking and seismic damage is also much greater areas on top of sediment rather than bedrock. Areas on a river, lake or coast where the land has been extended into the water by dumping fill dirt are the worst--ground shaking is really bad and they are very prone to liquefaction.
The difference between the arrival times (at any given point on earth) of the different phases of seismic waves is a function of the distance from the earthquake itself (the hypocenter) and the observation site. It is close to linear in Euclidian distance relatively near the earthquake hypocenter, but becomes more nonlinear farther from the earthquake, because the wave speeds are faster at depth (denser rock) so the travel paths of the wave fronts (the ray paths) are nonlinear. These differences in arrival times are one of the main ways of locating the hypocenter of an earthquake given observations from seismometers at multiple sites. It's essentially triangulation, except with time differences instead of angles--this is done through solving a system of equations.
Additionally, S-waves can't pass through liquids, so there is the 'S-wave shadow zone' that occupies a large fraction of the side of the earth opposite an earthquake where there are no primary S-wave arrivals--S-waves are blocked by the liquid outer core. This is how we found out that the outer core is liquid!
Yes, the speed of sound (through the earth, so faster than the speed of sound in air); yes.
In California, typically usgs has earthquakes posted before I can feel them. They didn't have this one a few minutes after I felt it, so I feel like automatic earthquake detection is off in this area of the US.
We felt it at 10:26 am ET. And an alert was sent to everyone at 11:24 am that an earthquake is coming. And then another one alerting for possibility of aftershocks. No aftershocks felt.
Same experience -- felt a shaking; thought maybe a heavy truck had passed by for a second, then saw that all the monitors were swaying. Checked USGS and saw nothing, so figured it was nothing, because on the west coast they have the reports up lickety split. Half hour later everyone's phone started buzzing with the automated alert.
Earthquakes propagate very slowly (around 2-8 miles/sec). That's how systems like ShakeAlert can send out early warning notifications. This one, for example, happened 40+ miles from NYC proper, so residents could have had like 20 seconds notice if the service operated here. People further up or down the coast could have had multiple minutes.
Same thing happened to me. I was on a facetime with someone in Brooklyn, but I was a 2 hour drive north outside of NYC and it took what felt like 30 seconds to propagate over that 200km.
Yes. Last time there was a fairly large one in the SF Bay Area I happened to be on the phone with some relatives about 40 miles away and I felt an earthquake a moment before they did.
Sure given the epicenter was in NJ and closer than Brooklyn. I am from Brooklyn, but live in Nyack, NY, and I felt it here. Nyack is 40mi from epicenter, Brooklyn ~60mi. But your experience could be different based on the structure you are in, floor elevation, and existing soil and ground conditions.
I assume they meant “propagation speed that is substantially slower than light in a vacuum” since that is less than 50ms between any two points on earth.
I felt it in Mass -- I was working on the second floor. My wife was on the ground floor and didn't feel it. From our internal slack channel, this seems fairly common -- people on the ground floor don't feel it here in MA, but higher floors, they do feel it.
Im on ground floor and definitely felt it. In brooklyn. All the buildings around me were visibly shaking. Felt like a freight train going by 10 feet away, but eerily quiet.
This was my second minor quake that could be felt in Mass. I was driving both times. First time I thought my steering felt suddenly rubbery. I was in a rotary. Didn't notice this one.
I actually do use Rumble (there are some more controversial-but-also-left-leaning creators that got banned from YouTube that I like), but man the ads on there are insane.
COVID conspiracy theories, vaccine "alternatives", political ads for obscure Republican candidates, stuff like that. Fortunately, at least for now there's not a lot of ads (I suspect that they can't find a lot of mainstream advertisers), so generally I only got to watch one of those ads before the video starts.
I don't know - for example, here is a video of a couple of scientists who explain in detail how they have analyzed the vaccine contents and how authorities then have reacted to their complaints:
I made it clear that these were the ads, not the direct videos.
That said, the COVID vaccines are safe and saying otherwise is kind of intellectually dishonest. Just because you can find one video where they "analyzed the vaccine contents" doesn't discount all the research and sampling data that has been taken.
If you haven't gotten the COVID vaccine, you probably should.
A number of years ago, in SoCal (where earthquakes are nothing too special), we had a similar sized quake (maybe a tad bigger). One guy from Denver was out and his eyes went big and wasn't sure what to do -- everyone else just kept talking and moved away from the big glass windows haha.
For my first quake in CA, I was peeing. (I'm a man and I pee standing up.) The shower doors next to me started to rattle, so I thought the people above me were jumping around. I didn't realize it was a quake! (The stream kept going where it was supposed to go.)
I came out of the bathroom and my roommate was terrified.
It was even funnier when my mom called me in a panic and I told her what happened.
Both me and my girlfriend were working from home today. Randomly our dog started crying and a few seconds later we felt the quake. Was pretty wild. Lots of rattling of furniture and plates in the cabinets. I guess my dog must have noticed the more subtle rumbles beforehand.
That one is easy: You won’t shock anyone if you show up at the hospital with dirty underwear. You don’t want a trauma surgeon to say that they have to page the neuro-chir. Get under a doorframe, and put your pants up when your head is safe.
I thought the door frame thing was actually not a good idea? The mantra nowadays is drop, cover and hold on. Which might actually put you in a more precarious situation during said quake.
I can honestly say it happened to me. It's a very strange experience- lasted about 40 seconds. I'm about 300km from where the epicenter was. The main thing i worried about was the building collapsing, and my state of dress and 'activity' would become the stuff of memes and "did you hear about....?" stories.
Considering the aftershocks are way less intense, probably not. I've felt 2 now, last one was just a few minutes ago, parents confirmed (they are about same distance from epicenter but I'm northwest, they are southeast of it)
I'm in Forest Hills (fifth story) and at first I thought it was the usual extreme wind we get because the windows were shaking heavily. Then it got worse and I realized what it was when I felt it through the floor.
I've felt at least one other in the last year or two here but my wife in the other room did not. This one was the strongest I've been through though.
East coast geology (older, harder rocks) causes earthquakes to feel about ten times stronger than a west coast earthquake. This is felt roughly the same as a 5.8 in California. That's enough to be notable, especially at a shallow depth.
I felt that one too in upstate NY, more of a rumbling that anything more violent. Doesn't even come close to the one I experienced in Peru one time, where everything felt like a ship on rough seas... never want to live through that kind of quake again!
That's one possible explanation, though I've been on usgs.gov a lot from the first I heard of this, and I've only ever seen 4.8 on it. Odd, also that the OP sharing this shared a link to 4.8 but put 4.7 in the title. But the text on that page might trick your eye, between "M 4.8 - 7 km N" and "Magnitude 4.8 mwr Depth 4.7 km".
Those of us in California are used to this. We feel the shake and look it up, and see one number. News articles get written with one of those numbers. After a while it changes, possibly a few times, to some number close to the initial report.
That helps. I must've just missed it when it said 4.7. Most articles just state 4.7 (or 4.8) though a few are now saying "preliminary magnitude of 4.7." By the time I saw it, it said M 4.8 mwr with uncertainty ± 0.0.
It went on for I guess 30 seconds or so. Everyone in the house completely confused as we had never been in a quake before. Very low level vibrations, very very loud sound. Very foreign to New Jersey folks!
This is the second quake I've felt in Pennsylvania. The first was in 2011. I was born here and lived here for my whole life except for 4 years when I lived in CA, where I didn't feel any earthquakes.
I was laying in bed and thought I'd sleep a little bit more. the earthquake wasn't violent, but certainly noticeable. It was similar to someone walking on my roof, without the banging.
The Belden quake is 4.4 at 7.8 km, and 4.2 at 5 km.
It's a log scale so the Whitehouse quake is much larger, but the significance of the quake seems to be more than just these numbers because Belden quake is irrelevant (didn't make the news really).
Sarupathar was a 5.8 (huge comparatively) at 10 km. Hualien was 5.1 at 15.9 km and talked about more than Sarupathar. So the defining aspect appears to be how many people are within range of the epicenter rather than just raw depth and magnitude. Which makes sense, I suppose. We care about how population centers encounter the movement!
Thank you! Yeah, a 7.4 is humongous. I did wonder about this because my wife's family reported quite intensive shaking and I've been in a 6-something before and that was quite disruptive. I can't imagine a 5.1 being that much.
I experienced a 4.8 earthquake about a month ago in Tokyo, and noticed the shaking significantly. In Manhattan this morning, I didn't notice the 4.7 earthquake at all.
Pretty common, but small and rarely noticed [0]. Probably lots of construction and geotechnical engineering wouldn't have survived anything significant at least in the Northeast
I'm in Manhattan (UWS) and live on the fourth floor of a five story walk-up. I felt the quake, but didn't realize that's what it was (I was a little confused as to why my building was vibrating -- for 40 seconds or so, as big trucks can do that but not for that long) until I received an emergency alert on my phone ~45 minutes later.
Nothing broken or dislodged, just wondering why my building was vibrating fairly gently.
We're almost exactly 10 miles north of the epicenter near Oldwick, NJ. We experienced several sharp jolts that sent some items tumbling off shelves and shook my ember full of coffee off its charging coaster (or I spilled it in reacting to the jolt, idk really), followed by a gentle shaking that lasted 30 seconds or more. This is the first one I can recall feeling since we moved here in 1995.
Earthquakes are apparently rare on the East coast. We had a 4.8/4.9 here near the census designated place of Belden in Plumas County CA yesterday evening. Others farther away felt it. I didn’t. Cats didn’t react either. Unless it’s a sharp quake, or in the mid 5s, I mostly don’t notice them.
Felt this all the way in Brooklyn. My wife and I thought it was just some heavy sustained road construction nearby; it was a bit shakier than usual for that, but the last thing we thought it was was an actual earthquake.
Fortunately, at least in our area, there doesn't appear to be any kind of damage.
Yep - felt it here in northern NJ, as did friends in NY and CT.
Working from home - all windows rattling/etc - first thought something was happening inside house, then looked outside expecting something massive driving by perhaps!
Kids at high school did classroom emergency shelter-in-place.
I’m about 10mi from the epicenter and noticed most of the aftershocks today. What’s interesting is there was a 2.2 a couple weeks ago at the same area and I thought I noticed it, but didn’t look it up at the time thinking it was just a truck nearby.
Our 4.0 earthquake in Youngstown, OH where there are NEVER earthquakes was caused by high pressure pumping of radioactive fracking waste fluids from the Marcellus shale play in Pennsylvania into the Northstar 1 Injection Well
In NYC. This was much stronger than in terms of local shaking than the others of the last 25 years. Living on the 4th floor of a 90+ year old building. My fridge was trying to walk across the floor.
...again. This is a Cat Cafe in Japan, and you can clearly see the cats get alerted to something ~10 seconds before the shaking starts. Do we have an idea of what they are reacting to?
Huh. You do hear about animals reacting before earthquakes. My cat did alert before the quake, but didn't really scoot, until the shaking started.
He was sitting on my lap, at the time. I'm glad he didn't extend his claws.
I suspect some kind of subsonics that come before the shaking really gets going. It can take a bit of time to get a rhythm going, so the earthquake may actually be under way for a bit, before we really feel it.
EDIT: just had another aftershock right after posting this. Felt the 2.0 a couple hours ago too
EDIT2: yup usgs finally added it https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma95...