Quake Watch 2011

reply to post by MamaJ

Thank you, MamaJ! That's good information and well worth having posted, both here and on the Arkansas Swarm thread.

I have some more comments to make but I'll place them in that other thread to keep the discussion going there.

Best regards,

Mike

Hmmm... Another quake in Chile about an hour ago:

Magnitude 5.7 - ANTOFAGASTA, CHILE
2011 October 30 18:53:43 UTC

Versión en Español

* Details
* Summary
* Maps
* Scientific & Technical

Earthquake Details

* This event has been reviewed by a seismologist.

Magnitude 5.7
Date-Time

* Sunday, October 30, 2011 at 18:53:43 UTC
* Sunday, October 30, 2011 at 03:53:43 PM at epicenter
* Time of Earthquake in other Time Zones

Location 25.812°S, 70.567°W
Depth 31.4 km (19.5 miles)
Region ANTOFAGASTA, CHILE
Distances 46 km (28 miles) S of Taltal, Antofagasta, Chile
174 km (108 miles) N of Copiapo, Atacama, Chile
239 km (148 miles) S of Antofagasta, Antofagasta, Chile
847 km (526 miles) N of SANTIAGO, Region Metropolitana, Chile
Location Uncertainty horizontal +/- 20.5 km (12.7 miles); depth +/- 7.7 km (4.8 miles)
Parameters NST=129, Nph=129, Dmin=254.9 km, Rmss=1.12 sec, Gp=137°,
M-type=body wave magnitude (Mb), Version=8
Source

* Magnitude: USGS NEIC (WDCS-D)
Location: USGS NEIC (WDCS-D)

Event ID usb0006glr

Source: USGS

Very close to the coast and not too far from Taltal. Hopefully no serious damage. Need to check for any reports from the region.

Mike

Double posted the above for some reason. But never mind, I'll scrub the dp details and add something new...

The EMSC actually has the above-noted Chile quake as offshore and with differences in mag and depth to USGS data. Not unusual to see that, though.

Magnitude mb 5.6
Region OFFSHORE ANTOFAGASTA, CHILE
Date time 2011-10-30 18:53:41.0 UTC
Location 25.75 S ; 70.75 W
Depth 10 km
Distances 184 km NW Copiapó (pop 129,280 ; local time 15:53:41.5 2011-10-30)
48 km SW Taltal (pop 10,018 ; local time 15:53:41.5 2011-10-30)

Source: EMSC

Mike

ML 6, revised down from 6.2 as per Chilean El Mercurio news article. Mercalli 5 intensity.

Depth 47.1 km

www.emol.com/noticias/nacional/2011/10/30/510529/sismo-de-6-grados-de-magnitud-se-registra-en-region-de-atacama.html

ssn.dgf.uchile.cl/events/sensibles/2011/10/20111030185250.html

Has anyone asked or explained why so many earthquakes appear to be very shallow, especially aroun the 10km mark, and is it normal?

It's like the 'skin' of the earth has a problem, rather than the 'muscles'

*Sneaks silently into the Thread,looks around and posts a Link for the Quake-Gurus*

Plate tectonics may control reversals in the Earth's magnetic field

The Earth's magnetic field has reversed many times at an irregular rate throughout its history. Long periods without reversal have been interspersed with eras of frequent reversals. What is the reason for these reversals and their irregularity? Researchers from CNRS and the Institut de Physique du Globe, France, have shed new light on the issue by demonstrating that, over the last 300 million years, reversal frequency has depended on the distribution of tectonic plates on the surface of the globe. This result does not imply that terrestrial plates themselves trigger the switch over of the magnetic field. Instead, it establishes that although the reversal phenomenon takes place, in fine, within the Earth's liquid core, it is nevertheless sensitive to what happens outside the core and more specifically in the Earth's mantle. This work is published on 16 October 2011 in Geophysical Research Letters.

*Looks around again to see if someone noticed him and silently sneaks out again*

reply to post by Shenon


Mm. Anyone got any good ideas as to why this article seems to be at odds with at least three others which have some similarity to each other and are published in the same magazine? It is almost as if these 'scientists' have misread one of the other papers. Two different ideas even come out of the same Institut de Globe.

Scientists. God bless their little cotton socks white coats.

ETA: Symmetry/asymmetry of the magnetic field has been turned into symmetry/asymmetry in the flow of molten iron in this article. No explanation is given why the change from the other three articles. (Which all say something similar but slightly different.)

reply to post by SpaceJockey1

Q: Why do so many earthquakes occur at a depth of 10km?

A:

10 km is a "fixed depth". Sometimes data are too poor to compute a reliable depth for an earthquake. In such a case, the depth is assigned to be 10 km. In many areas around the world, reliable depths tend to average 10 km or close to it. For example, if we made a histogram of the reliable depths in such an area, we'd expect to see a peak around 10 km.

Continued in USGS FAQs

Depth
The depth where the earthquake begins to rupture. This depth may be relative to mean sea-level or the average elevation of the seismic stations which provided arrival-time data for the earthquake location. The choice of reference depth is dependent on the method used to locate the earthquake. Sometimes when depth is poorly constrained by available seismic data, the location program will set the depth at a fixed value. For example, 33 km is often used as a default depth for earthquakes determined to be shallow, but whose depth is not satisfactorily determined by the data, whereas default depths of 5 or 10 km are often used in mid-continental areas and on mid-ocean ridges since earthquakes in these areas are usually shallower than 33 km.

USGS Glossary

Earthquakes at shallow depths are a result of stick-slip faulting, however, below about 50 km the hot, high pressure conditions ought to inhibit further seismicity. The mantle is also considered to be viscous, and so incapable of brittle faulting. However, in subduction zones, earthquakes are observed down to 670 km. A number of mechanisms have been proposed to explain this phenomenon, including dehydration, thermal runaway, and phase change.

The geothermal gradient can be lowered where cool material from the surface sinks downward, increasing the strength of the surrounding mantle, and allowing earthquakes to occur down to a depth of 400 km and 670 km.

Wiki

....
Rocks hotter than about 300 degrees Celsius flow in response to stress, they do not rupture in earthquakes
....

Wiki: Earthquake

Sorry, being lazy I guess!! Add to that the fact that for instance in the Moho project and other deep drilling projects the temperatures were approaching this.

However, due to higher than expected temperatures at this depth and location, 180 °C (356 °F) instead of expected 100 °C (212 °F), drilling deeper was deemed unfeasible and the drilling was stopped in 1992.[4] With the expected further increase in temperature with increasing depth, drilling to 15,000 m (49,000 ft) would have meant working at a projected 300 °C (570 °F), at which the drill bit would no longer work.

Kola superdeep borehole

So what this is saying basically is that rock at around 15km deep is approaching the 300 deg mark at which point it is plastic enough not to support seismicity. This is why the bulk of earthquakes are above that level.

Someone posted this in another thread around 5:30 pm. in Kentucky.

Keep alert you peeps in NMSZ area.....this is the second or third time since May that these anomalies have been witnessed.


We just observed earthquake lights for about 10-20 minutes to the southwest of our location in Kentucky. The general direction of New Madrid! I've never seen these weird lights before! A relatively small bright spot in the sky with pink to the right and blue-green colors to the left of it. In the middle it was yellowish-white. It came for a few minutes and went away then returned for a few minutes in the same place in the sky.

Also a sulfur smell in our water which has never been there before until a few weeks ago.

reply to post by radpetey


Could you direct me to this thread please.
I am from Kentucky and my family lives there.
Thanks in advance.

reply to post by PuterMan


Hm,something about those Earthquake-Lights got me thinking...PuterMan,would you be so kind and tell me when Mag 8+ happened,say in the last 10 Years? During the Day or during the Night? Maybe even if they are mostly in the Morning,Lunchtime or Evening if you have the Time.

Thanks in advance

reply to post by Shenon


Hi Shennon,

Here is the list of mag 8 in the last 10 years

DateTime,Latitude,Longitude,Depth,Magnitude,MagType,NbStations,Gap,Distance,RMS,Source,EventID
2001/06/23 20:33:14.13,-16.2650,-73.6410,33.00,8.40,Mw,518,,,1.05,NEI,2001062340
2003/09/25 19:50:06.36,41.8150,143.9100,27.00,8.30,Mw,669,,,0.88,NEI,2003092540
2004/12/23 14:59:04.41,-49.3120,161.3450,10.00,8.10,Mw,331,,,1.12,NEI,2004122340
2004/12/26 00:58:53.45,3.2950,95.9820,30.00,9.00,Mw,601,,,1.17,NEI,2004122640
2005/03/28 16:09:36.53,2.0850,97.1080,30.00,8.60,Mw,510,,,0.91,NEI,2005032840
2006/05/03 15:26:40.29,-20.1870,-174.1230,55.00,8.00,Mw,626,,,1.18,NEI,2006050340
2006/11/15 11:14:13.57,46.5920,153.2660,10.00,8.30,Mw,576,,,1.07,NEI,2006111540
2007/01/13 04:23:21.16,46.2430,154.5240,10.00,8.10,Mw,606,,,1.12,NEI,2007011340
2007/04/01 20:39:58.71,-8.4660,157.0430,24.00,8.10,Mw,439,,,1.32,NEI,2007040140
2007/08/15 23:40:57.89,-13.3860,-76.6030,39.00,8.00,Me,625,,,0.86,NEI,2007081540
2007/09/12 11:10:26.83,-4.4380,101.3670,34.00,8.50,Me,411,,,1.03,NEI,2007091240
2009/09/29 17:48:10.99,-15.4890,-172.0950,18.00,8.10,Mw,520,,,1.01,NEI,2009092940
2010/02/27 06:34:11.53,-36.1220,-72.8980,22.90,8.80,Mw,454,,,1.09,NEI,2010022740
2011/03/11 05:46:24.12,38.2970,142.3730,29.00,9.10,Mw,541,,,1.16,NEI,2011031120

ANSS Search

If I get a minute later I will try and find locations and day/night but i have some work to complete first.


Silly me, I just remembered that USGS have a list.

Magnitude 8 and Greater Earthquakes Since 1900

Note that the first one in my list (the first of the last 10 years) was almost where the current quakes are in Peru

neic.usgs.gov...

www.timeanddate.com... to assist in working out local time if you get bored and beat me too it.






PSS If you link to the USGS details from that this the majority of the have local time there for you so you should be able to work out day/night etc.

Signing off for a while!!!

reply to post by crazydaisy


Hey Crazy Daisy,

Enclosed is the thread you requested.

I wish I knew how to condense the whole thing to just that one post. It is at the end of that first page....I think

www.abovetopsecret.com...

Happy Halloween ATS community

So, I was just wondering if anyone else in Virginia is feeling the small quakes this morning? I started feeling tremors about 3 hours ago, especially when I am sitting at the compy. I'm about 90 miles NW of Mineral, where the Mag 5.8 from August was located. I pulled this screenshot from GEE a few minutes ago. The amplitude scale from the Corbin, Va seismo normally runs in the 3 to -1 micron/sec range, during normal Monday mornings. USGS doesn't show anything yet (and probable won't).

click to enlarge

Hope I am just feeling more shake out from the August quake, and not another one building up. I am still feeling the earth move as I type. Feels like I'm floating on a raft in the lake

ETA: Here is a link to a temporary station near Hopewell Church


Here is a screenshot from 16:20UTC, the amplitude is larger still.

reply to post by PuterMan


Yep,thanks. Don´t know if i have the Time either since the Debt-Crisis gets worse by the Day,so take your Time

Its just a hunch anyway. I think it would be nice to know where the Sun is at for the Majority of the bigger Quakes. Might answer some Questions if the Suns and/or our own Magnetic Field have anything to do with Earthquakes.

reply to post by Shenon


This might help, all Mag 8's in the last 1697 years (with times in UTC where available) with locations
List
Interactive Map
I had a quick look using the map through NZ and Kamchatka areas where I know the corresponding conversion to local time (either +/-12hrs) and its about 50/50 am/pm

FWIW
Date/Time: 1811/12/16 2:00:00 Local
Lat: 36.6 Long: -89.6
Location: USA:[New Madrid EQ1](Missouri)
Magnitude: 8.0 Unk
Depth: - km

Date/Time: 1812/1/23 15:0: UTC (9:00:00 a.m local)
Lat: 36.6 Long: -89.6
Location: USA:[New Madrid EQ2]
Magnitude: 8.0 Unk
Depth: - km

Date/Time: 1812/2/7 9:45: UTC (3:45:00 a.m local)
Lat: 36.6 Long: -89.6
Location: USA:[New Madrid EQ3]
Magnitude: 8.0 Unk
Depth: - km
Source: Coffman, von Hake and Stover (1982)

Originally posted by radpetey
Someone posted this in another thread around 5:30 pm. in Kentucky.

Keep alert you peeps in NMSZ area.....this is the second or third time since May that these anomalies have been witnessed.


We just observed earthquake lights for about 10-20 minutes to the southwest of our location in Kentucky. The general direction of New Madrid! I've never seen these weird lights before! A relatively small bright spot in the sky with pink to the right and blue-green colors to the left of it. In the middle it was yellowish-white. It came for a few minutes and went away then returned for a few minutes in the same place in the sky.

Also a sulfur smell in our water which has never been there before until a few weeks ago.

Hey ,I saw those "lights" yesterday about that time.
It was just sundogs,thats all.
There was one on either side of the sun,quiet a distance from the sun.
I don't know about any sulfur smells,though.

reply to post by kdog1982


Thanks for letting us know -
I was thinking perhaps it
was Sun Dogs. At least
they had a good show.

reply to post by crazydaisy

Hey crazy daisy.
This is pretty much what I saw. I see them all the time.

reply to post by kdog1982


Neat picture. Ice crystals those are. We get that here in Ireland as well. It is the same thing that causes noctilucent clouds.

Don't know about sun dogs - I thought they were camera artefacts, but I am not a photographer so I may be wrong.