| Earthwatchers
|
[
Earthwatchers ] [ Main Menu ] |
|
|
|
97318 |
|
|
Date: September 18, 2023 at 21:25:33
From: Daisy/CA, [DNS_Address]
Subject: at least a 5 in Paterson at 9:15 pm |
|
|
|
Felt that one! About 1/2 hour away. Everything and everyone ok.
|
|
|
|
|
Responses:
[97322] [97326] [97328] |
|
97322 |
|
|
Date: September 18, 2023 at 21:47:12
From: EMY1, [DNS_Address]
Subject: Re: at least a 5 in Paterson at 9:15 pm |
|
|
|
|
|
|
|
Responses:
[97326] [97328] |
|
97326 |
|
|
Date: September 19, 2023 at 00:33:09
From: Redhart, [DNS_Address]
Subject: Re: at least a 5 in Paterson at 9:15 pm |
URL: https://seismo.berkeley.edu/hayward/hayward_history.html |
|
There's a line of faults that run along the west side
of the Central valley associated with the subsidence of
the valley in relation to the thrust of the coast
mountains. The quake and aftershocks run perpendicular
(E-W) and between the San Joaquin vault (marking the
western boundry of the central valley in a N-S
direction at this area) and the Greenville fault which
runs N-S through the Diablo range to the east of the
bay area.
The quake today shows first motion as a thrust
fault..which track with an unnamed, small branch thrust
fault.
This is probably not the major fault..but a minor off
branch step tracking nearly east west through the
diablo range close to the Central valley. Compressional
forces of the north American plate are moving to the
wsw against the pacific place (boundry is the San
andreas).This will cause occasional folding in the
Diablo range.
This is a small, mountain thrust fault and probably not
capable of more than a 6 . Would love to see how this
quake affected the stresses in nearby
faults...Greenville, Hayward and Calaveras (strike-
slip)to the west...San Joaquin (normal faulting) to the
east...all capable of larger quakes. Sometimes these
small branch faults act like stress tethers..helping to
lock down larger faults until the tether breaks and
moves the stress around.
Odds are, this is it. The multiple quakes is the
aftershock sequence that will fill in the actual fault
movement planes as it readjusts to it's new position.
Of course, Mother earth does sometimes shoot off a
longshot (a larger quake on a nearby fault it has
shifted stresses to). But, that would be a rarer
occurrence, but cannot be ruled out ..though a much
less chance. Hayward fault hasn't had a large quake
since 1868 and is overdue and closely watched:
"... The last major earthquake that the Hayward fault
produced was in 1868. At the time, it was known as the
'great San Francisco quake' (this was before the
infamous 1906 quake, produced by the San Andreas
fault), and it produced massive amounts of damage and
several people lost their lives...."
|
|
|
|
|
Responses:
[97328] |
|
97328 |
|
|
Date: September 19, 2023 at 18:35:27
From: eaamon, [DNS_Address]
Subject: Re: at least a 5 in Paterson at 9:15 pm |
|
|
|
I wonder if they pumped too much water out from under the valley.
|
|
|
|
|
Responses:
None |
|
[
Earthwatchers ] [ Main Menu ] |