36 replies to this topic

[Lighthawk]

Thanks for the info, Ted.  Since we can't get outside with all the smoke and forest closures, this might be the best time for Julie to get her knees done.   Ice that knee! 

[teledork]

Three quakes so far this morning. I definitely felt the 2.9 and 3.8 with epicenters within sight of my house and I say "so far" because they seem to come in clusters. Some days there are none, other days serve us a 6 - 7 course meal. The 2.6 just east of Bridgeport  may have been what woke me up a little after 5 am. 

 

A couple of weeks back someone reported a count of 78 earthquakes of a minimum magnitude (I can't recall - was maybe 2 or above?) in a single week. Another week and we will have had three months of this. 

 

I brace when I hear a truck go by on the highway and have had more than one night with little to no sleep unless I have some "white noise" (a ten hour recording of a stream) 

 

The kind of funny thing is that I grew up in the SF Bay area. Most people think that is earthquakesville. From my experience they would be incorrect. The other kind of funny thing is that I was not at hone for the main event (although it scared the pants off of me on the shore of a lake in the backcountry) and I have still had more than enough of this. 

[teledork]

Okay. the one that I thought may have been a continuation of #3 was a separate quake with an epicenter just down the slope from #2 and #3 and a magnitude of 3.5 so make that 4 quakes so far. 

Edited by teledork, 28 September 2021 - 04:16 PM.

[Foy]

And the South Carolina Lowcountry is getting in on the act yesterday (Monday 27 September) having recorded two earthquakes of 2.9 and  3.3 magnitude near Summerville.  Summerville, SC was the approximate epicenter of the regionally infamous Charleston Earthquake in 1886, estimated to have been between 6.9 and 7.3 magnitude. Not widely known is the fact that many long regional faults occur more or less parallel to the present coastline throughout the Piedmont and Coastal Plain all the way from NY into GA.  Most are mapped as border faults forming grabens and half-grabens (sedimentary basins) resulting from the breakup of the supercontinent of Pangea in the Triassic. Many of them, including the Jonesboro Fault running between Raleigh and Durham, NC have several  thousand feet of up-down vertical  throw. Outside of the Coastal Plain, the basins outcrop as readily identifiable unmetamorphosed sedimentary rocks, mostly red sandstones and shales, with some basaltic flows, sills, and dikes.  There are a slew of these "Triassic Basins" (25 or 30 or more?) up and down the East Coast and at  least that many more have been identified beneath younger Coastal Plain sedimentary overlap on the mainland of VA, NC, SC, and GA and probably another dozen or two beneath the same younger rocks offshore  on the Continental Shelf. The present-day SC earthquakes as well  as the Charleston quake are believed  to  have occurred along these Triassic faults buried thousands of feet under the younger Coastal Plain rocks.

 

Foy

[teledork]

Welcome to the party, Foy!

 

We need some music: 

[Casa Escarlata Robles Too]

It can be unnerving with all those small shakers.

 

We get a few here along the Monterey Bay as we are

about 10 miles from the San Andres fault.

Frank

[Foy]

Welcome to the party, Foy!

 

We need some music: 

 

Why thanks very much for the serenade! 

 

We're really not devoid of earthquakes in the East, just not a lot of big'uns.  Back in August 2011, we had a 5.9 or so in the Virginia Seismic Zone located in the Piedmont around 120 miles from my Raleigh, NC home.  Brought some widespread and mostly minor structural damage. I felt it plain as day--took me about 3 seconds to realize what it was--just long enough to look out my office window the the "passing truck" which wasn't there.  The northwestern corner of NC had a 5.3 up in the Blue Ridge in July or August 2020--widespread and mostly minor structural damage. But the Midwest/Deep South claims the Big Daddy events east of the Rockies--the New Madrid quakes of 1811-1812.  Some were estimated to have been 7.7 magnitude.  Fissures opened up, widespread soil liquifaction, sand blows, Mississippi River running backward, sudden formation of 15,000 acre Reelfoot Lake due to subsidence of 1.5 to 6.0 meters along the Reelfoot Fault.  Quite the series of events from December 1811 to February 1812.

 

Foy

[Casa Escarlata Robles Too]

I remember Reelfoot Lake from the "Mickey Mouse" club series, The Mystery of Reelfoot Lake.

Guess I am dating myself a bit.

 

The stories of the New Madrid quake are interesting.

Thanks for the  geology facts/info.

Frank

[teledork]

Every time I think to myself; " hasn't shaken in a while" it does.  

[Casa Escarlata Robles Too]

Big story in the Sunday SF paper about the Rodgers Creek fault in the Napa area.

It may be the next "BIG" one so they say.

 

Haven't felt one in my area for some time.

Maybe saying that will stir the "quake" gods.

Frank