Earthquake in the Carolinas just now?

reply to post by gardener

From the Quakewatch thread -

Shallow--only 3.0 miles deep.

My novice mind is wondering if it could be related to the recent temperature extremes.

Shallow means it's more likely it was manmade

Like, a test mini nuke, or 1 being detonated to make room for newers ones?

Or a threat to move into Syria. Same old, same old terror state.

Jbird
reply to post by gardener

 

From the Quakewatch thread -

Shallow--only 3.0 miles deep.

My novice mind is wondering if it could be related to the recent temperature extremes.

I didn't even think about that, but it is an interesting coincidence if nothing else. I know the Carolinas and this general area have weird weather, but I was thinking this is getting a bit ridiculous. Below freezing lows to 70s highs in a week; 6-8 inches of snow and sleet to 50F+ in 24 hours?!

Before the great San Fransisco quake of 1906, South Carolina was thought to the most seismic active areas in the country. Charleston, SC had a great quake in 1886.

Earthquakes in South Carolina are nothing new.

GA just had a 4.1?

Did someone post that already?

ETA: Same one...sorry.

Great first post. I just put up my first tonight as well, but I think that this has been a truly strange week for shaking and quaking. Linda Howe put up a post about more sky quakes in MN ( www.earthfiles.com... ) , we had Corvettes falling into sink holes and now your rare rumble. Strange , strange week.

Doomsbury
Great first post. I just put up my first tonight as well, but I think that this has been a truly strange week for shaking and quaking. Linda Howe put up a post about more sky quakes in MN ( www.earthfiles.com... ) , we had Corvettes falling into sink holes and now your rare rumble. Strange , strange week.

Thanks Just my first thread though, I do post from time to time but I do more lurking than anything. This place is so busy sometimes I feel like I'd just be repeating 5 other people or way behind in the discussion if I join in!

I read about the Corvette sinkhole, that actually made me a little sad.

So they don't know which fault it is?

Faults Earthquakes everywhere occur on faults within bedrock, usually miles deep. Most bedrock beneath the inland Carolinas was assembled as continents collided to form a supercontinent about 500-300 million years ago, raising the Appalachian Mountains. Most of the rest of the bedrock formed when the supercontinent rifted apart about 200 million years ago to form what are now the northeastern U.S., the Atlantic Ocean, and Europe.

At well-studied plate boundaries like the San Andreas fault system in California, often scientists can determine the name of the specific fault that is responsible for an earthquake. In contrast, east of the Rocky Mountains this is rarely the case.

The inland Carolinas region is far from the nearest plate boundaries, which are in the center of the Atlantic Ocean and in the Caribbean Sea. The region is laced with known faults but numerous smaller or deeply buried faults remain undetected. Even the known faults are poorly located at earthquake depths. Accordingly, few, if any, earthquakes in the inland Carolinas can be linked to named faults. It is difficult to determine if a known fault is still active and could slip and cause an earthquake. As in most other areas east of the Rockies, the best guide to earthquake hazards in the seismic zone is the earthquakes themselves.

USGS

Now that the Transportable Array is in its eastern phase (dispersed in a tight network all over the eastern US), I was able to look up a station quite close to the epicenter. So close, in fact, that this quake clipped the station. This is from station TA.Y55A. From the S&P differential, I estimate this station to be about 34 to 38 km from the epicenter. I also downloaded the raw seismic data with my rig, and I have a couple pretty pictures for you's-

Here is the helicorder plot I generated of it (I cropped just the quake):



And here is the associated amplitude waveform and spectrograph:



Being that I live in Western North Carolina, I am surprised I didn't feel it, but then again, I was at work, just coming off a break. But I am on it, live monitoring that station in case another one happens. Don't see any aftershocks yet. I wonder if I'd actually feel it before my rig registers it, being that close and all. That's a toss up.

Here's a map of SC faults. The quake happened in Edgefield Co, where the yellow arrow is, of which the Eastern Piedmont fault system runs right thru. We locals call it the fall line, the separation btwn the flat lands and the piedmont hills. The soil changes from grey clay in the flatlands to sandy in the sand hills to red clay up here in the piedmont. You can see the fall line real clear on a google map, runs right across the middle of the state.

I'm in Charleston, someone as talking about hearing about it, we didn't feel anything.

reply to post by TrueAmerican


Hi TA! Glad you're here and monitoring it! Thanks for the pretty pics and graphs. It clipped the the station??? Wow. I had forgotten about the portable arrays they have set up. Can you tell me if I'm right in that it was a reverse fault based on USGS Moment Tensor pg? I have a hard time understanding their info 'cause I'm not that tech oriented, just enough to get me into trouble!!!

reply to post by SCGrits


Yes, I believe you have Identified that correctly as a reverse fault, but there are people here who can read those better than me. Very good though! Star for joo!

reply to post by TrueAmerican


Good catch! This is why ATS is great. I never would have thought to check for something like that, but again I'm not very versed in the subject of tectonics and such.. I'll be going to bed soon but I will come back to see the results, if any. I would think any aftershocks to this would be difficult to feel without equipment. ETA: Unless you were closer to the epicenter, of course.

reply to post by duke396


Thanks, and glad to be of help.

I must say though, quakes that big in such a strange spot make me a little nervous when no aftershocks occur. Could be a foreshock, but let's hope the heck not.

reply to post by TrueAmerican


Well people have been saying for years that we're overdue for another "big one"...

NW GA reporting in:
I didn't feel a thing, but my cat sure did. She jumped up my lap and had her very best insanity face on. (Big eyes, ears turned sideways. The kind of expression that says " the voices want me to borrow your zippo").

Then again, maybe she just wanted my lighter.
She is an awfully irresponsible cat..

reply to post by DC434L2A


Lol, I'd keep an eye on that cat if I were you! Funny things animals are. My dog is pretty laid back most of the time (6 year old Pit) and he had no reaction to this at all that I saw. Pretty sure he slept through it until I finally stood up to go ask if anyone else felt it.

duke396
reply to post by TrueAmerican

 

Well people have been saying for years that we're overdue for another "big one"...

Yeah well, that's probably on the New Madrid you are referring to? Or are you talking about Charleston?

On another note, a little birdy and I are having a conversation behind the scenes, though it might interest you:

They state:

Recent weather extremes in that area - simply coincidence or possibly related ?

My response:

Possibly a connection. The quake was shallow, and who knows, maybe the weight of all that snow melting today created a sort of glacial rebound effect, setting off the fault. *shrugs* Not sure.

reply to post by TrueAmerican


I was thinking more local than that, on the map shown earlier in the thread one appears to pass through York / Chester / Lancaster counties so pretty much under my feet. But the New Madrid would probably be more of an issue.

That is an interesting idea you have there. I wonder if there's any connection between this instance, and times of the past where we have gotten large (for the area, at least) amounts of snow compared to when our earthquakes happened. I don't really have the energy to research that right now but I may end up looking into it tomorrow after work. It always melts pretty quickly here, usually gone from roads in a day or two and no trace at all within a week so I wonder what kind of effect that could have.

ETA: I'm hesitant to be the one to say this year's weather is more extreme than the last, because it seems like people say that every year here. I've never bothered to actually check historical data to confirm or deny...

ETA again: Just saw this article from my area about the quake last night, for anyone who may be interested.
www.heraldonline.com...

The quake at 10:23 p.m. was centered on the edge of Thurmond Lake, just north of the area hardest hit by this week's snow and ice storm.

Hmm.