West Coast USA: Pay Attention, Cascadia May Be Ready to Rupture

reply to post by JohnVidale


So where was the smaller event from then, you got an event ID for that one?

reply to post by TrueAmerican


Both events are way west of the region for which our network is "authoritative". More to the point, they are way outside where our locations are accurate. So we didn't separately locate the two events, in fact we didn't post a location for the M4.9, we just deleted the M2.1, and let the NEIC location represent the big event. NEIC is unlikely to find nor post the small event.

In fact, Paul tried to locate both events and had great trouble, which was part of the delay in taking down the M2.1.

I'm not sure if this is clear. Basically, the M2.1 located in our area, but that location was wrong, so we aren't following up.

reply to post by JohnVidale


Ok, thanks much John. Boy am I glad you're around to explain this from an internal network point of view. Quakes disappearing from suspect spots make for good conspiracy fodder- when in fact there was a reasonable explanation. I am surprised you guys still allow auto location at all for quakes off the coast, considering so many of them have proven to be flat out wrong.

reply to post by TrueAmerican


It's a little more complicated than that. Nothing gets posted until someone looks at the GIF to see whether an event really happened, and if the parameters look plausible. These offshore ones are tough, and someone made a small mistake in letting it post an M2 just off the coast from those waveforms. It can be tough to tell, especially looking at the waveforms on a cell phone. Also, usually we fix mistakes more quickly, but here we were hung up with the two-event confusion.

reply to post by JohnVidale


Would there be any advantage at all to putting seismometers out on the sea surface on buoys? Even if you can't read the S-waves (because water, a liquid, does not support shear stress)- it would still help in locating some of the events offshore. Has anyone considered this?

reply to post by TrueAmerican


The noise from sensors at the surface would be prohibitive. Seismic signals usually move the ground only microns to millimeters, and you can imagine the amplitude of motions bobbing on the waves.

We'd love a set of OBSs on the sea floor, even though they would be noisy, but we're talking $20-50M, at least, to install them, and more to run them. That's a factor of several more than the entire land set-up costs, and it would be fairly insensitive and hard to maintain.

Didn't Oregon get an EQ today? Sizable...kinda?? Would that EQ be revelant within the context of what's going on?

It seems I've heard of some animal die offs again too...

reply to post by tracehd1


M5 off Oregon, but way off. Not associated with the subduction zone.

I think we got another quake coming in off the coast....stay tuned...Observed at station COR...not real big or anything... and it could take a bit...


Yep. Another 4.5:
earthquake.usgs.gov...

Hey true seems like first the north part shakes than the south part. This eq went off first than the 4.5 off the coast of Oregon.

Earthquake Details

This event has been reviewed by a seismologist.
Magnitude
5.6
Date-Time
Thursday, August 09, 2012 at 02:34:41 UTC
Wednesday, August 08, 2012 at 07:34:41 PM at epicenter
Time of Earthquake in other Time Zones
Location
19.902°N, 109.140°W
Depth
9.6 km (6.0 miles)
Region
REVILLA GIGEDO ISLANDS REGION
Distances
241 km (149 miles) NE of Socorro Island, Mexico
337 km (209 miles) SSE of Cabo San Lucas, Mexico
350 km (217 miles) S of San Jose del Cabo, Mexico
405 km (251 miles) W of Puerto Vallarta, Mexico
Location Uncertainty
horizontal +/- 18.5 km (11.5 miles); depth +/- 3.9 km (2.4 miles)
Parameters
NST=326, Nph=333, Dmin=833.8 km, Rmss=1.55 sec, Gp=173°,
M-type=regional moment magnitude (Mw), Version=B
Source
Magnitude: USGS NEIC (WDCS-D)
Location: USGS NEIC (WDCS-D)
Event ID
usb000bsqa

USGS info

This was in our local paper this morning:

www.news.com.au... ory-fncynjr2-1226446246156

reply to post by TrueAmerican


AW DAMN. I knew canada would screw us over eventually.

reply to post by BottledWater


Hey.. we would row away from you guys if we could...
but seriously,really? time to get out my flippers and water wings

just had another 4 off the coast of cali


Earthquake Details

This is a computer-generated message -- this event has not yet been reviewed by a seismologist.
Magnitude
4.3
Date-Time
Thursday, August 09, 2012 at 15:24:24 UTC
Thursday, August 09, 2012 at 08:24:24 AM at epicenter
Location
40.757°N, 125.217°W
Depth
2.5 km (1.6 miles) (poorly constrained)
Region
OFFSHORE NORTHERN CALIFORNIA
Distances
83 km (52 miles) WNW (284°) from Ferndale, CA
85 km (53 miles) W (272°) from Humboldt Hill, CA
87 km (54 miles) W (270°) from Bayview, CA
89 km (55 miles) W (268°) from Eureka, CA
404 km (251 miles) NW (309°) from Sacramento, CA
Location Uncertainty
horizontal +/- 1.6 km (1.0 miles); depth +/- 29.7 km (18.5 miles)
Parameters
Nph=126, Dmin=81 km, Rmss=0.36 sec, Gp=238°,
M-type=regional moment magnitude (Mw), Version=4
Source
California Integrated Seismic Net:
USGS Caltech CGS UCB UCSD UNR
Event ID
nc71828881

USGS

Geesh TA, you are making John V use his brain while on vacation. But I do have to say I am learning from and enjoying your posts- both of you.

Originally posted by bluemirage5
This was in our local paper this morning:

www.news.com.au... ory-fncynjr2-1226446246156

I can't get your link to work. Is that an Australian paper?

Well here is another

Earthquake Details

This event has been reviewed by a seismologist.
Magnitude
5.6
Date-Time
Sunday, August 19, 2012 at 08:07:36 UTC
Saturday, August 18, 2012 at 11:07:36 PM at epicenter
Time of Earthquake in other Time Zones
Location
47.773°N, 128.625°W
Depth
10.1 km (6.3 miles)
Region
OFF THE COAST OF WASHINGTON
Distances
253 km (157 miles) SW of Tofino, Canada
326 km (202 miles) WSW of Port Alberni, Canada
341 km (211 miles) SW of Courtenay, Canada
352 km (218 miles) SW of Campbell River, Canada
Location Uncertainty
horizontal +/- 17.7 km (11.0 miles); depth +/- 4.5 km (2.8 miles)
Parameters
NST=492, Nph=494, Dmin=165.9 km, Rmss=0.92 sec, Gp=148°,
M-type=regional moment magnitude (Mw), Version=8
Source
Magnitude: USGS NEIC (WDCS-D)
Location: USGS NEIC (WDCS-D)
Event ID
usc000c2x2

USGS INFO

I'm calling shenanigans!

First, the Cascadia Transportable Array goes offline on Saturday the 18th at approximately 05:54UTC, and finally came back online early this morning...

Now, the Plate Boundary network goes mysteriously offline at 18:55 UTC. (check out any of the links on this page for day 233)

What is going on Earthscope?...please...


Suspiciously, this occurs only two minutes after this small Mag 2.2 just east of Seaside, Oregon at an interesting depth. (BTW, this quake can be seen nicely on borehole B020 and B024 at the link above.)

What don't 'they' want us to see?
[/end tin-foil moment]

In all seriousness, I find the quakes on this map more interesting when you change the setting to show depths.
What is causing all of the shaking in the blue, lavender, and black range (11-64km deep)?
Mountain building? The subducting Juan de Fuca?


Uh, nevermind. The PBO seems to be functional again...nothing to see here, lol.



Well, just to show that the PBO was having an issue, check out this PNSN webi of B020. Missing data.

reply to post by Olivine


Steve spent a couple of days trying to nail down the cause of that missing TA data. It did come back, and maybe related to fire-hosing of data into a slow machine, but we're not entirely sure yet. I'll tell Steve the thought arose that we were hiding something.

If you were watching carefully, you might have seen us waffle about whether some quakes were tectonic or highwaymen or quarrymen blowing up stuff, and switched the labels back and forth.

reply to post by JohnVidale


Hi John I was just being silly--I don't believe there was anything nefarious afoot. It's a conspiricy site--I was trying to join in.

Looking at seismos, I do have a question. This is the link for UW.TIMB.EHZ over the past 6 hours.
What do you see from 22:40 to 23:30 UTC?
My untrained eye sees many very, very tiny earthquakes. Is it just wind or traffic?