8.6 earthquake in China???--01-27-2010

[Cinderella]

here is a news article posted today (28th of Jan) that talks about some Chinese EQ that happened on the 24th this month.

"Wuhan, China — The China Earthquake Network Center detected an earthquake of 4.8 magnitude on the Richter scale in Yuancheng county of China’s northern Shanxi province last Sunday, Jan. 24. It was not a big earthquake and there were no reports of damage, casualties or interruption of people’s lives. However, compared with this external shock, the internal shock was much bigger – local authorities had just refuted a “rumor” about an “expected” quake in the area.


"Further, the experts emphasized that rumors should not be believed or spread, as earthquake forecasts must be made by the government and individuals had no right to issue such announcements. Hence, after the actual quake on Sunday, those experts lost face due to their previous denials to the media."

http://www.upiasia.com/Politics/2010/01/28/chinas_unscientific_rebuttal_of_earthquake_rumors/6809/

Any surprise China tells there people not to believe anything about EQ's unless it comes from the government? If this doesn't show some of China's true colors I don't know what will. I wonder what other EQ rumors were going around China as of late...

There also is at least two more sources claiming that this earthquake has taken place.

http://www.emsc-csem.org/index.php?page=current&sub=alert&id=FIZ24;BUC

http://www.infp.ro/ro/origins/5055-ronet

http://aslwww.cr.usgs.gov/Seismic_Data/telemetry_data/QIZ_24hr.html

I was able to find this. I'm no good at interpreting the data though. Perhaps someone here can?

http://aslwww.cr.usgs.gov/Seismic_Data/heli2.shtml

I am finding it hard to lend any credibility to this so far, there would be at least SOMETHING out there about it. its just weird that a few different stations picked up on the earthquake independently. I don't know what could have caused this to happend. Is it a common occurance to get false siesmology readings ?

 

[Cinderella]

I checked the coordinates on google earth and that region seems to be completley mountainous with no real population for miles, could that be why it`s not been reported? Simply not affecting many people.

Regiune: SICHUAN, CHINA
Latitudine: 31.5311N
Longitudine: 108.9173E
Adancime: 15km
Data/Ora: 27.01.2010, 18:51 (UTC)
Magnitudine: 8.6 ( mb=8.6 )

http://www.infp.ro/ro/origins/5055-ronet

 

[rancher89]

maybe there's oil there??

 

[Cinderella]

did you even bother to look at anything before you posted your smart-ass remark?

 

[Ethek]

8.6 is huge. Any sandy soil close to the surface and it might has well have been water for any structure on the surface. Liquifaction of soil is an oddly devestating phenomenon.

 

[MelissaWV]

8.6 is a ridiculously huge earthquake... even if in an isolated region, depending on the quake it would have been widely felt. (edit: I've since looked around on the internet, and we've had some 8+ in recent history that didn't cause a huge panic.)

I am curious as to real-time images of the area during the alleged quake. An 8.6 in the kind of terrain you described would throw up some airborne evidence, I would think, in the form of dust clouds, etc..

With an isolated region like that, the possibility would also exist that it's a weapons test. The sheer SIZE of that earthquake makes it very unlikely, but if anyone has the resources to be testing a new bomb underground right now, it's China.

I find it far more likely that equipment has somehow malfunctioned at some observatories. To answer your question directly, though, I don't think a false reading of this size is common at all.

* * *

An interesting thing is to search for "8.6 earthquake" and see how many articles do pop up about a China earthquake. The USGS website, for what it's worth, shows a 5.0 on January 24 and that's it.

 

[rancher89]

did you even bother to look at anything before you posted your smart-ass remark?

Listen, I didn't intend it to be taken that way, earthquakes elicit from me a defense mechanism that is sometimes a little off. Been through to many of them, hate them. sorry

 

[Cinderella]

But you'd think if some sort of bomb testing were the cause that the seismic data would be turned off... maybe someone forgot let it slip into the stats online and now they're trying to cover it up?


it has not been confirmed this was an EQ. Something making the scales read MAG 8.6 that isn't an EQ is pretty scary to think about. This could be a good reason the Chinese haven't come out to say anything yet. Time will tell

 

[Zippyjuan]

As many know, the Richter Scale is logrithmic- a 2.0 quake releases ten times the energy that a 1.0 quake does. According to information at Wiki http://en.wikipedia.org/wiki/Richter_magnitude_scale an 8.5 quake would release the energy equal to 5.6 gigatons of TNT. By comparison, the largest explosion ever detonated was the Tsar (nuclear) Bomb in Russia, 1961 which had an estimated yield of 50 megatons- that would have been about a 7.1 earthquake if it was in the ground (it was an air detonation) so an 8.6 would be about 15 times bigger than that. The bomb dropped on Nagasaki would have been the aproximate energy of a 5.0 quake. There is not a known weapon with enough energy to cause an 8.6 quake.

It is highly unlikely (if not impossible) for there to have been an actual quake of that magnitude which would not have been picked up by other quake monitoring stations around the world.

Closer examination of the information provided indicates that they are not using the Richter scale (they say mb=8.6). ML would be Richter.

Magnitudine: 8.6 ( mb=8.6 )

http://neic.usgs.gov/neis/phase_data/mag_formulas.html

ML = log A - log Ao
defined by Richter (1935) where A is the maximum trace amplitude in millimeters recorded on a standard short-period seismometer and log Ao is a standard value as a function of distance where distance <= 600 kilometers.

mb = log (A/T) +Q(D,h)
defined by Gutenberg and Richter (1956) except that T, the period in seconds, is restricted to 0.1 <= T <= 3.0 and A, the ground amplitude in micrometers, is not necessarily the maximum in the P group. Q is a function of distance (D) and depth (h) where D >= 5°.

MB is "Compressional Body Wave (P-wave) Magnitude" and ML is Local Magnitude. I am looking for any comparisons between the two (they are actually measuring different things so they may not be comparable) but that could explain an 8.6 mb and the 4.6 Richter reported in the first article in the original post. They are two different types of waves generated by quakes. Kind of like the different colors of the light spectrum. There are even other quake wave measurements too such as MS and MW.

This article abstract discusses the problems with using different measures for quakes so maybe there is not currently any reliable conversion between the two:
http://www.springerlink.com/content/pwqk306gr8172t38/

Abstract The existence of several magnitude scales used by seismological centers all over the world and the compilation of earthquake catalogs by many authors have rendered globally valid relations connecting magnitude scales a necessity. This would allow the creation of a homogeneous global earthquake catalog, a useful tool for earthquake research. Of special interest is the definition of global relations converting different magnitude scales to the most reliable and useful scale of magnitude, the moment magnitude, M W. In order to accomplish this, a very large sample of data from international seismological sources (ISC, NEIC, HRVD, etc.) has been collected and processed. The magnitude scales tested against M W are the surface wave magnitude, M S, the body wave magnitude, m b, and the local magnitude, M L.

It looks like there was NOT an 8.6 Richter scale quake in China.

 

[MelissaWV]

Knew I could count on you, Zippy

 

[Cinderella]

Knew I could count on you, Zippy

i thought the same...i knew it wouldnt be long before he popped in