M 4.8 – 2024 Whitehouse Station, New Jersey Earthquake
earthquake.usgs.gov
earthquake.usgs.gov
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...
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.
[1]: https://scholar.google.com/scholar?hl=en&as_sdt=0%2C48&q=dam...
[2]: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/200...
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)
Magnetic hard drives are sensitive to vibration. You can shout at hard drives and measure the effects (video: https://www.youtube.com/watch?v=tDacjrSCeq4).
One of the worst-case scenarios is a head crash. A head crash will damage the media and may result in data loss. https://en.wikipedia.org/wiki/Head_crash
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.
- Personnel-level warning to immediately rerack servers, close racks, and get off ladders and away from fall hazards
- Proactively spin up generators to reduce failover in the more-likely event of a power disruption
- Potentially temporarily shut off very large circulation fans so that blades don't collide with the housings
- Potentially stop and carefully restart cooling water loops, in case there's a rupture in the system somewhere
Add to this: initiate failover or zone transfer of distributed servers / services to other DCs outside the likely impacted area.
https://typhoon.yahoo.co.jp/weather/jp/earthquake/kyoshin/
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:
https://typhoon.yahoo.co.jp/weather/jp/earthquake/2024040412...
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?
The math ain’t mathing.
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
And I definitely agree, the 2011 one was more of a sway, this felt like a rumble.
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)
But seriously, I hope everything is fine.
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.
Equivalent in lateral motion/shakiness to a California 6.0 due to the shallow depth of the 4.8
Most local magnitude scales are
>>> 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]
[1] https://en.wikipedia.org/wiki/Richter_scale
[2] https://earthscience.stackexchange.com/questions/22348/what-...
>"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.
https://en.wikipedia.org/wiki/Modified_Mercalli_intensity_sc...
NYC has had 5.x earthquakes that have caused e.g. chimneys to collapse, something unheard of in california.
The parent posted decimals.
As you said, they are not the same thing.
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.
I am getting anxious just thinking about this. With all those sky scrappers..
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.
Watching all the water slosh around as the building swayed was... disconcerting.
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!
Literally: a cold hurricane.
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.
…but they’ll be fine with a ‘a big cold cyclone’ I guess ;)
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!
That's not nothing.
The Midwest gets MS Paint eraser tool tornadoes.
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.
[0] https://www.usgs.gov/news/featured-story/east-vs-west-coast-...
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.
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"
Generally: concerns of an extra-human, non-biological origin. E.g., JMA doesn't address pandemics.
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.
[1] https://www.npr.org/sections/thetwo-way/2014/01/30/268720258...
Plus the Northeast is just not made for quakes. The 200 year old house I grew up in would probably have creaked pretty alarmingly.
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.
What!?! We have some doozies here in the summer. (Finger Lakes region of NY.)
We have a word for that...smart.
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.
Oregon is full of volcanoes and about to slip off the continental shelf, right? But I guess those surprises just exists in potential form.
I'd put the constant wildfires in the weather thing bucket.
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.
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 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.
The PNW does get tremendously powerful Pacific cyclones every so often [0]. These are huge storms that would do real damage to mid-Atlantic cities.
And there's the known risk of the "big one" -- subduction zone quake, Seattle fault, etc. Sleep tight East coast, you'll be fine.
[0] - https://www.climate.washington.edu/stormking/mainindex.html
Edit: Here it is. It was the end of August which I consider the Fall cause that's when the Fall semester starts for me ^^ https://en.wikipedia.org/wiki/2011_Virginia_earthquake
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?
Do earthquakes have a propagation speed? Might she have felt it before me?
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.
Some industrial equipment shuts down to avoid damage.
But in summary, the speed is slower than light, so yes you can find out through telecom faster than it getting to you.
[0] https://www.google.com/maps/place/40%C2%B040'58.8%22N+74%C2%...
Surface waves yes, body waves not necessarily. But surface waves are more destructive.
Frustrated network architects would disagree!
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!
First thought was it was an earthquake, but then no signs other than that I could feel it in legs.
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.
https://rumble.com/v4n6hsn-analysis-on-covid-19-vaccines-per...
Would you still call such content a conspiracy theory?
The subtitles open with "so-called vaccine against COVID-19" and "with all this fraud that is which is being carried about by the WHO".
These vaccines have been seriously studied for year and now billions of people have taken them. Safe enough, ok?
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.
Thankfully the surgeon wasn't "scalpel deep" during the quake!
https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma7c...
https://earthquake.usgs.gov/earthquakes/map/?extent=40.4809,...
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.
https://stationview.raspberryshake.org/
Not a ton of coverage in the area but it was picked up.
Last time something like this happened was 25 years ago…
https://www.usgs.gov/observatories/yvo/news/aftershocks-swar...
https://earthquake.usgs.gov/earthquakes/map/?currentFeatureI...
This event is identified as the potential mainshock of an earthquake sequence.
From this URL: https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74...https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma7c...
EDIT: waiting for usgs to update with latest but here's all the ones associated with event https://earthquake.usgs.gov/earthquakes/map/?currentFeatureI...
The weird thing was, just before it happened I heard/felt a very peculiar thrumming in my ear, like the air was exerting vibrating pressure.
They say that animals can detect earthquakes before they happen. I think I might have an idea as to how.
(1)https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74...
4.7 quake at 1 km depth will shake more at the surface than a 6.0 at 30 km depth
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.
APNews did something similar showing 4.8 in the headline but 4.7 in the text.
Coincidentally the depth is 4.7 km. Wonder if there's just a transpose error and a lot of copy/paste.
For example some of the data comes from stations on the other side of the planet, and it takes a while for the wave to propagate that far.
Also interesting is the list of two "catalogs" with mostly similar data but very different depth reports: https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74...
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!
Of course now I've jinxed myself.
Looks like reported depth was 5km, making this a very shallow earthquake
I’m about 15 miles from the epicenter.
NYC quake was at shallow depth.
4.7 quake at 1 km depth will shake more at the surface than a 6.0 at 30 km depth
https://earthquake.usgs.gov/earthquakes/map/?currentFeatureI...
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!
That's just an aftershock.
The main quake was three days ago. M 7.4 according to USGS: https://earthquake.usgs.gov/earthquakes/eventpage/us7000m9g4...
So for an earthquake that's almost 1000x as strong, you'd think it'd be talked about more.
> Since 1950, 40 other earthquakes of magnitude 3 and larger have occurred within 250 km of today’s earthquake
[0] https://earthquake.usgs.gov/earthquakes/map/?extent=38.03944,-79.33228&extent=45.75219,-63.86353&range=search&showUSFaults=true&baseLayer=terrain&timeZone=utc&search=%7B%22name%22:%22Search%20Results%22,%22params%22:%7B%22starttime%22:%221900-01-01%2000:00:00%22,%22maxlatitude%22:42.816,%22minlatitude%22:41.2,%22maxlongitude%22:-69.593,%22minlongitude%22:-73.592,%22minmagnitude%22:0,%22orderby%22:%22time%22%7D%7DNothing broken or dislodged, just wondering why my building was vibrating fairly gently.
Right now in Huntington
Fortunately, at least in our area, there doesn't appear to be any kind of damage.
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.
You would feel it more the higher up you are as the building resonates.
I thought it was construction vehicles. We've had a lot of heavy construction around here.
What made it clear it was different, was my cat didn't like it, and he ignores the construction.
https://www.youtube.com/watch?v=VJ-p9qOhBv4
...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?
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.
I'm pretty observant with that sort of thing, so I'm a bit surprised.
Is it even possible for someone a few houses away to experience drastically different seismic activity?
Edit: I was on the ground floor, which is likely why I did not feel it.
> Is it even possible for someone a few houses away to experience drastically different seismic activity?
I'm not sure but there's probably variables around how sturdy things are (the foundation, floor, walls, desk, monitors, etc.). If I tap the side of my desk with the force of a golf clap the monitor wobble factor it about equal to the earthquake. I know in the US it's funny to measure things with weird units but that's the best I can do to associate the amount of force.
10 or 20 minutes later my phone starts buzzing informing me that there had been an earthquake. Seems rather pointless.
https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74...
Sitting at home in my office in Ozone Park NYC and I hear what I think is a low flying plane coming in to JFK. Happens when weather is bad and they come in lower they can rattle my windows. But the intensity grew suddenly and my entire house was shaking and everything was rattling.
At first I froze for a few seconds as I could not make sense of what I was experiencing - but it was clear this was not normal so I ran like hell downstairs and outside. While running I was trying to make sense of the shaking: did a truck or plane crash? no not this long - maybe the elevated A train up the block is collapsing? An explosion? some kind of cataclysm? WTF is happening! But after I reached the side door and the house was still shaking I realized this is an earthquake. Earthquake was not the first thing on my mind for sure as I have lived in NYC all my life and never felt anything like this.
Fucking nuts
Hearing tornado sirens for the first time was wild, especially as a Silent Hill fan.
On the other hand my friend moved to Brooklyn from Haiti after their terrible quake so he's in a mood right now.
In the middle of the night I was awoken by what I thought was a large truck out front, like a garbage truck or something. But it kept getting closer and more intense and everything started shuffling around in the house with a shik-shik-shik-shik noise and the blinds started rapping off each side of the window sill. When you experience something new like this where your brain kind of spins around in circles not knowing what to do, then it came back with the answer of Earthquake! which I involuntarily yelled out loud. My next thought was "Is this going to get worse, and what do I do if it does". I was in a new place that I had barely even looked at before falling asleep. Thankfully it subsided after 20 seconds or so without any major incident. Was hard to fall back to sleep that night.
Yeah, I slept through that.
i hate that feeling, a few weeks ago i was walking my dogs and surprised by a pitbill and some other mix that immediately attacked my two small dogs. It took like 5-10 seconds for me to even figure out what was happening and what to do about it.
Also, do we know if Bruce Springsteen is okay?
For all our sakes, I hope that’s not the case.
DO NOT get into a doorway, that's a myth. It's not a terrible place to be if it's a doorless frame, but if there is a door, it's more likely you get injured from the door smacking you than the earthquake.
DO get under a strong table. That's the safest place to be in a quake if it happens when you are indoors.
If you're outside get as far away from trees and power lines as possible (and glass), but if the ground is shaking too hard to maintain balance, stay in place. Again, you're more likely to get injured falling down than from whatever may be nearby.
If you're inside and not near a table, at the very least cover your head if possible and move away from bookcases and other tall or top heavy objects.
Also, if you did feel it, please help the USGS study earthquakes by filling out a Did You Feel it survey: https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74...
But in my single family home situation it really doesn't take more than a few seconds and I can be out the door provided I'm not knocked off my feet entirely type situation.
It might be interesting to somehow determine earthquake injuries / ability to get in or outdoors and measure the real risk from actual events.
Plus you'd be surprised how hard it is to even stand straight during particularly strong quakes yet alone walk/run, there's no possible description I can give to explain adequately how strange it is to feel the ground underneath your feet shaking violently, especially in buildings.
In California, even saving yourself from being on fire is taxed.
I guess my fellow Californians can be a little touchy about taxes.
I'm still not sure what I'm supposed to be holding onto. Do I briefly cover my head with my arms, then stop covering my head to hold onto the table? Do I hold onto my head while I cover it? Do I cover my loved one's head and they cover mine, sharing our last moments in a loving hold?
Now I'm beginning to wonder if I made a massive assumption that I would be covering my head with my hands. That's what I would do during a tornado, but maybe I'm supposed to be covering my head with a blanket so my hands are free for the hold on part?
Honestly, my facetious hold my bladder advice seems more apropos than anything I've managed to come up with for part three.
DROP or DUCK down to your hands and knees
Take COVER protecting your head/neck with an arm and crawl under a sturdy table/desk possible or to a nearby interior wall away from potential falling objects
HOLD ON to your shelter if you have it or head/neck with both hands if you don't
It's not as obvious as stop, drop and roll which is why drills are a thing in schools.
It's also not terribly far from duck and cover drills for nukes or tornadoes as I understand it. The hold on bit was added to keep people from tripping and breaking a leg while running around while the ground is shaking.
I grew up on the west coast and that's exactly how it was taught to us in public schools.
The weak ones don’t prepare you for the strong ones.
I’ve been rocking and rolling in So Cal for decades. I’ve felt most of the major quakes that have made the news. I’ve seen stuff fall from my walls, transformers short out and explode. Felt rollers, thumpers, shakers.
We’ve had four of note at my house this year alone so far. One of them felt like it picked the house up and dropped it several inches.
Each time, they were never severe enough to get me to dive for anything. It’s just like that dinner scene in LA Story, where they just grab their glasses and carry on.
Then, you see videos of “real quakes”. Stuff out of movies. File cabinets sliding across the floor. Bookcases falling. Heavy things tossed like they weigh nothing, not to mention the larger damage.
Having been through my series of quakes, I can see they’re nothing like a major one. But, right now, my gumption when one shows up is wait and see. Perhaps not the best habit. But when you’re in bed at night, and a small roller hits and it feels like you just dropped a quarter in the slot to turn your bed on, hard to get motivated to get up and out and duck and cover.
Better just to roll over, say “it’s ok honey” to my wife, and go back to sleep.
In other parts of the world, it'll depend on the local building codes and their enforcement.
$ git config --global alias.subduct rebase