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97347 |
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Date: September 30, 2023 at 08:56:32
From: eaamon, [DNS_Address]
Subject: 4.7 Norhtern CA |
URL: 4.7 North coast |
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Responses:
[97349] [97355] [97351] [97352] [97353] [97356] [97359] [97360] [97357] [97358] [97354] [97348] [97350] |
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97349 |
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Date: September 30, 2023 at 11:03:59
From: eaamon, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
URL: 4.2 quake |
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Responses:
[97355] [97351] [97352] [97353] [97356] [97359] [97360] [97357] [97358] [97354] |
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97355 |
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Date: September 30, 2023 at 16:45:45
From: Eve, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
URL: https://www.msn.com/en-us/weather/topstories/2-earthquakes-strike-northern-california-hundreds-of-miles-apart/ar-AA1huGXv |
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Earthquakes struck Northern California in two regions hundreds of miles apart
Saturday morning, according to the U.S. Geological Survey.
A 2.7 quake hit at 7:45 a.m. around Bridgeport (Mono County) near the Nevada border,
the USGS reported.
About 460 miles away, a 4.7 quake struck at 8:26 a.m. about 2 miles southwest of
Ferndale (Humboldt County), on the coast about 60 miles south of the Oregon border.
It was followed by a 3.7 quake about 60 miles west of Petrolia (Humboldt County) at
9:36 a.m. Saturday, the USGS said.
A 4.9 quake struck off the coast of Northern California at 10:16 a.m., the same time
as a 4.2 quake 9 miles southwest of Ferndale, the USGS said.
Reports of damage were not immediately available.
— Chronicle staff
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Responses:
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97351 |
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Date: September 30, 2023 at 11:05:00
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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Responses:
[97352] [97353] [97356] [97359] [97360] [97357] [97358] [97354] |
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97352 |
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Date: September 30, 2023 at 12:57:48
From: Redhart, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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Strike slip on the focal mech & moment tensor
(beachball). So, not the subduction fault, or a
thrust/normal fault..sideways movement.
In your area, it's important to know because you really
don't want to see or hear from the megathrust fault off
the coast as a possible precursor.
Much rather have those occasional strike slips.
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Responses:
[97353] [97356] [97359] [97360] [97357] [97358] [97354] |
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97353 |
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Date: September 30, 2023 at 13:46:16
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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those were probably aftershocks from the rio del quake a few months ago...pretty deep though...the more concerning quake was the one the other day south of willow creek...40 some miles inland... about 17.5 mile down, in the subduction plane...
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Responses:
[97356] [97359] [97360] [97357] [97358] [97354] |
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97356 |
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Date: October 01, 2023 at 10:04:23
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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and one more today...
Time: Oct. 1, 2023, 8:41 a.m.
Magnitude: 3.9
Coords: 40.2996674°N, -124.2866669°W
Depth: 5.68 miles
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Responses:
[97359] [97360] [97357] [97358] |
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97359 |
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Date: October 01, 2023 at 13:04:59
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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and
Time: Oct. 1, 2023, 12:29 p.m.
Magnitude: 3.6
Coords: 40.2970009°N, -124.2868347°W
Depth: 5.41 miles
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Responses:
[97360] |
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97360 |
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Date: October 01, 2023 at 13:55:02
From: Redhart, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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that one was oblique: part slide part thrust.
Probably a minor mountain fault readjusting to the
stressed from a stress shift of the primary quake.
(aka: an aftershock)
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Responses:
None |
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97357 |
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Date: October 01, 2023 at 10:25:59
From: eaamon, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
URL: 4.1 upgrade |
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I can only guess they up graded today's to a 4.1.
I keep thinking about the three series 5.1 to 5.2 and 5.4 quakes in August
just prior to the Loma Prieta '89 quake.
just a warning or is it just the super moon being so close to earth.
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Responses:
[97358] |
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97358 |
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Date: October 01, 2023 at 11:01:38
From: Redhart, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
URL: https://en.wikipedia.org/wiki/Mendocino_Triple_Junction |
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Yeah, I was there for the pre-shocks and remember them
vividly (one woke me up from a sound sleep).
Also remember this was not a normal set...actual
warnings went out from the USGS for two weeks causing a
big stir. Everyone put their pictures back up on the
wall after two weeks and sighed a sign of relief, and
the Loma Prieta quake came 2 months after the preshock.
The USGS was right, just had the timing off.
It was clear enough to seismologist at the time that
these preshocks were "Something special".
The problem with this Mendocino Triple Junction area is
it's very complex. You have the Mendocino fracture, the
San Andreas AND the Cascadia subduction zone all
joining in one place. Add to that intra-plate quakes
both off shore on the ocean plates, and on shore as the
mountains thrust and dip and crumple under all these
stresses, and I'm sure the USGS wishes it was a easy as
the Loma Prieta quake preshocks (which is not to say
that's easy at all). The Triple junction is just way
more complex, too much so to say with any certainty
whether it's pre-shock or just the hyper active area
patters.
The Triple junction has one of the highest rates of
seismicity, and one of the most complex fault systems.
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Responses:
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97354 |
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Date: September 30, 2023 at 14:17:51
From: Redhart, [DNS_Address]
Subject: Re: 4.7 Norhtern CA,now 4.2 |
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yeah, that would raise some warning flags for me. I'd
put a "watch" pin on that.
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Responses:
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97348 |
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Date: September 30, 2023 at 08:59:54
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA |
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felt it...short shaker...4-5 seconds...
Time: Sept. 30, 2023, 8:26 a.m.
Magnitude: 4.7
Coords: 40.5541649°N, -124.2723312°W
Depth: 10.13 miles
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Responses:
[97350] |
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97350 |
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Date: September 30, 2023 at 11:04:24
From: ryan, [DNS_Address]
Subject: Re: 4.7 Norhtern CA |
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aftershock of the aftershock...
4.2M Earthquake 15 Kilometers Southwest of Ferndale
Time: Sept. 30, 2023, 10:16 a.m.
Magnitude: 4.2
Coords: 40.4980011°N, -124.4046631°W
Depth: 16.35 miles
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Responses:
None |
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