None of the people in my ground-floor office in Allston (a neighborhood in Boston) felt any tremors. However, my girlfriend's office in the Cambridgeport neighborhood of Cambridge shook, and was evacuated for about 20-30 minutes.
A colleague (we're in NJ) was on the phone with Toronto, and the Canadians felt it a short time (10 seconds?) after we did. How fast do these things travel?
Well, let's suppose you're in Trenton, NJ (since you didn't specify). The distance between Trenton and Toronto is 546 km. If it took 10 seconds to travel there, then it was traveling at 54.6 km/s, or 196560 km/hour. For comparison, the speed of sound is 340.29 m/s, or 0.34029 km/s; that means that the shockwave travelled at Mach 160.
Of course, this assumes that it was traveling over the surface, so it's really lower than this, but I'm unsure of how much. From what I'm seeing, the fastest earthquakes generally travel about 13 km/s, so this may be way high.
About 10 years ago during a minor earthquake in the California Bay Area, I happened to be on the phone with my girlfriend at the time who was in Mountain View, I was in San Jose. The conversation went something like:
GF: "Oh! There's an earthquake!"
Me: "What, no there isn-- Oh wow, there's an earthquake!"
(few seconds of shaking)
GF: "Okay, it's over"
Me: "No it isn't, I stil feel-- Oh yeah, it's over!"
I'd estimate the delay to have been ~2-3 seconds over ~20 miles -- but I don't remember where the epicenter was, or how deep the quake was.
Can someone who knows something about geology comment: is it normal for semi-large earthquakes to be correlated like this? When we went to Google News, the first thing we found were other earthquakes in Colorado and off Indonesia.
I'm not a geology expert by any means, but I've lived in SF my whole life.
Generally any quake comes with a corresponding set of tremors based on the initial quake. These tend to be along the same or related fault lines. The Colorado quake could be related. Indonesia probably not as much.
But think about it logically. Earthquake is a quick release of kinetic energy of a tectonic plate in one relatively small location. But the whole plate moves! So yes, earthquakes happening on the same plate's boundary can very well be correlated, IMHO (not pretending to be a geology expert or anything, but the topic is fascinating).
Virginia is not in any way connected to Pacific Ring of Fire though.
Not a geologist but I'm married to one. That makes me an expert geologist at parties right?
Anyways, Indonesia would be totally unrelated, it's part of the Ring of Fire, geological activity there is expected and their big one happened on Sunday. Stuff today is just aftershocks.
Colorado and Virginia might be correlated since it's uncommon (but not unexpected) for stuff east of the Rockies to rattle about but I'd lean towards it just being a coincidence since they're 12 hours (05:46:19 UTC and 17:51:03 UTC) and ~2650 km apart.
It is near 0% likely that the Colorado earthquake and Virginia earthquake are related as VA and CO are on different faults. It's not 0% because, quite frankly, it's hard to model the earth.
This wikipedia article on plate tectonics explains how the Earth crust is composed of different sections all sliding past/under each other. http://en.wikipedia.org/wiki/Plate_tectonics Since the earthquakes occur at the friction points between the plates, this should help explain why Japan and California has a lot, and Virginia and Colorado not so much.
One of the major problems humans have with earthquakes is the assumption that we should/can predict them. As such, whenever there are earthquakes close in time to one another, the first assumption is that the first earthquake caused the second. Aftershocks are such an example where this assumption holds because the primary earthquake causes secondary earthquakes. However, in the general case, this assumption does not hold.
Just felt it in Toronto on the 9th floor. I was the only one that actually tried to leave the building. That worries me about what people would do in bigger earthquake.
Felt in Northern NJ. I thought it was the construction crews currently working on the building. I'm just curious, but isn't this magnitude in this area exceedingly rare?
I'm in Charlottesville Va, just a few miles from the epicenter, really scary stuff for a place not use to them. People were running out of buildings and it appears to have taken out a few cell towers. Hopefully no aftershocks.
Oh man, they're closing offices here in C-ville now, looks like there is a worry of possible aftershocks. Hope you guys stay safe, this all probably sounds ridiculous to you guys in CA.
It was centered 1 mile away from the Lake Anna nuclear reactor. Fingers crossed that their safety record was top notch... I can't reach anyone down there to check.
Felt it in south jersey. Shook my house quite a bit, even knocked some things off the kitchen counter. Lasted quite a while (felt like close to a minute).
My office reception is typically horrible, but I had just enough time to make an earthquake joke on FB(priorities, I know) before my data and phone reception crapped out. I blame network saturation.
Felt it in Raleigh, North Carolina. Quite strong, and made the whole house shake for quite a while. Figured it was some workers digging outside the apartment. Apparently not.
>I'm happy I don't have to experience this often, like in California.
Erm... We don't experience this often in California... I definitely felt the '89 quake, probably felt one in the 90s and I think I felt a quake a few years ago. So I've felt them once per decade.
Further, CA has built relatively well to account for earthquakes and doesn't have a giant off-shore shelf waiting to collapse and drown us under a tsunami[1], so we have that going for us, which is nice.
The first and third are the same spot, but a slightly different angle and distance. The wall has three framed photos, and when the shaking stopped, I knew something was wrong there right away there since they were at crazy angles.
123 comments
[ 4.5 ms ] story [ 144 ms ] threadIn the 3rd floor of a ~20 floor Boston office building I felt two mild tremors around 1:55pm, maybe 10 seconds each with a 10-second pause in between.
Of course, this assumes that it was traveling over the surface, so it's really lower than this, but I'm unsure of how much. From what I'm seeing, the fastest earthquakes generally travel about 13 km/s, so this may be way high.
GF: "Oh! There's an earthquake!"
Me: "What, no there isn-- Oh wow, there's an earthquake!"
(few seconds of shaking)
GF: "Okay, it's over"
Me: "No it isn't, I stil feel-- Oh yeah, it's over!"
I'd estimate the delay to have been ~2-3 seconds over ~20 miles -- but I don't remember where the epicenter was, or how deep the quake was.
http://imgs.xkcd.com/comics/seismic_waves.png
Generally any quake comes with a corresponding set of tremors based on the initial quake. These tend to be along the same or related fault lines. The Colorado quake could be related. Indonesia probably not as much.
But think about it logically. Earthquake is a quick release of kinetic energy of a tectonic plate in one relatively small location. But the whole plate moves! So yes, earthquakes happening on the same plate's boundary can very well be correlated, IMHO (not pretending to be a geology expert or anything, but the topic is fascinating).
Virginia is not in any way connected to Pacific Ring of Fire though.
Anyways, Indonesia would be totally unrelated, it's part of the Ring of Fire, geological activity there is expected and their big one happened on Sunday. Stuff today is just aftershocks.
Colorado and Virginia might be correlated since it's uncommon (but not unexpected) for stuff east of the Rockies to rattle about but I'd lean towards it just being a coincidence since they're 12 hours (05:46:19 UTC and 17:51:03 UTC) and ~2650 km apart.
It is near 0% likely that the Colorado earthquake and Virginia earthquake are related as VA and CO are on different faults. It's not 0% because, quite frankly, it's hard to model the earth.
This wikipedia article on plate tectonics explains how the Earth crust is composed of different sections all sliding past/under each other. http://en.wikipedia.org/wiki/Plate_tectonics Since the earthquakes occur at the friction points between the plates, this should help explain why Japan and California has a lot, and Virginia and Colorado not so much.
One of the major problems humans have with earthquakes is the assumption that we should/can predict them. As such, whenever there are earthquakes close in time to one another, the first assumption is that the first earthquake caused the second. Aftershocks are such an example where this assumption holds because the primary earthquake causes secondary earthquakes. However, in the general case, this assumption does not hold.
The gravity of this situation is clear in Italy where seismologists are on trial for manslaughter for not predicting the L’Aquila earthquake: http://www.nature.com/news/2011/110526/full/news.2011.325.ht...
The open letter in support of these seismologists is here (I'm #4580): http://www.mi.ingv.it/open_letter/
http://www.youtube.com/watch?v=tDacjrSCeq4
http://www.wavy.com/dpp/news/local_news/august-23-earthquake
Erm... We don't experience this often in California... I definitely felt the '89 quake, probably felt one in the 90s and I think I felt a quake a few years ago. So I've felt them once per decade.
Further, CA has built relatively well to account for earthquakes and doesn't have a giant off-shore shelf waiting to collapse and drown us under a tsunami[1], so we have that going for us, which is nice.
[1] http://modernsurvivalblog.com/earthquakes/earthquake-east-co...
The first and third are the same spot, but a slightly different angle and distance. The wall has three framed photos, and when the shaking stopped, I knew something was wrong there right away there since they were at crazy angles.