Thousands of buildings collapse after China quake

Agence France Presse | November 26, 2005

[HAL9000]

Thousands of buildings have collapsed and 11 people have been killed after a strong earthquake rattled east China on Saturday morning (local time).

The China National Seismic Observation Network says the quake measured 5.7 on the Richter scale and struck at 8:49am.

A local official has told AFP a total of 8,072 buildings have been destroyed in Jiujiang county as a result of the quake.

"Six people were killed in Jiujiang county," the local official said.

"Another 247 were injured and 8,072 buildings were toppled."

An official in nearby Ruichang city says five people have been killed there, while 39 have been injured.

He says the casualty figures from the two locations do not overlap.

[Alia]

You'd already be seeing headlines of "Chinese nuke test undeground" if it was a nuke.

I wish I had your confidence in saying such a thing. Who would report it? The people, via the internet? When censorship is such a big thing in a country, to a country; it is difficult to not worry or be concerned. It definitely takes a number of eyes to "assess" the situation, IMHO.

[Alia]

I've lived all my life in earthquake zones. Did some work over a number of years with CA Seimologists. Not a seismologist. That bottom "graph" "event in question". The after "rigor" is more lean and less erratic (and in duration) than the charts I've seen over a 30-year period for a 5.4. Not to say it couldn't have been a "jolt" quake. Given that the depth wasn't so deep, I can understand 8000+ buildings shaken like crazy. But I do not understand only 6 deaths. Given the not-so-deep depth of the "quake", debris would have been tossed all over the place. Meaning.. there should have been more casualties.

I wonder.

[Alia]

Addendem: "Buildings are measured as "rooms". Say average house had two rooms. 4,000 buildings. Say not so-average houses had 6 rooms each.. Where was everyone hiding when the quake hit?

[Spktyr]

When the seismographic recording looks like a nuke test (as posted in some of the followup posts above), that's what I call it.

They might have been testing something new and didn't want it exposed as it would be at Lop Nor.

[Alia]

Note to self: In re "burst/pulse" U.S. seen vulnerable to space 'pulse' attack

[GOPJ]

Sounds more like a nuclear accident. Tests aren't usually done in the morning when people are going to work. Too obvious.

[Victoria Delsoul]

At this point, I'd say that there is a 40% chance or better that the seismic event in question was an actual nuclear test in China.

Interesting. Let me know about further developments, thanks.

[Southack]

Figure 7.2: Examples of the seismic signals from a French nuclear explosion, recorded at a few stations in Europe at distances of around 10,000 miles. These seismograms, i.e., records of ground motion (note the horizontal time scale, in seconds), are spaced vertically at distances corresponding to their distance from the source at Mururoa. These seismic waves are known to be naturally amplified (focussed) for distances around 16000 16300 km, by virtue of features within the Earth's fluid core. For purposes of monitoring Mururoa from distant parts of the globe, clearly one would choose stations DPC, MORC and WET over the remaining four. (However, none of these stations are in the IMS list.)

[Victoria Delsoul]

Oh, pretty neat - I see it. Thanks Southack.

[Southack]

[Southack]

Here's the portion of the Chinese seismic graph (morning of Nov 26, 2005) that is in question:

[Southack]

Typical seismogram of a real earthquake:

[Southack]

1995 Kobe earthquake

[Southack]

Soviet nuclear test and Japanese seismogram 
 
Далее, на иллюстрациях изображены записи японских сейсмографов.
 

[Southack]

Return to Sumatra-Andaman Islands Earthquake Page   Download the full image (PDF -- very large file)

Broadband seismometers recorded ground motions from the Sumatran earthquake "on  scale" at locations worldwide.  At Richter magnitude M=9.0, the Sumatran quake is the largest seismic event in 40 years.  The scale of motion is unprecedented in modern seismic recordings.  When converted into units of displacement, the peak-to-peak ground motions observed worldwide commonly exceed one centimeter, mainly in the long oscillations (100+ sec) of the Love (G) and Rayleigh (R) surface waves.  Motions of the P (pressure) and S (shear) waves, which travel through Earth's deep interior, range from 0.1 to several mm at typical stations.  To appreciate the magnitude of the 26 December 2004 Sumatran earthquake, the lower panels of the graphic compare its P-wave ground motion at an observatory in Europe with motion recorded for the 17 January 1994 Northridge earthquake (M=6.7), which caused an estimated 60 deaths and property damage in excess of $20 billion in the Los Angeles area.  Two facts bias this comparison slightly in favor of the Northridge event: (1) GSN station ESK is somewhat closer to the Northridge epicenter (75.1 degrees) than the Sumatran epicenter (92.4 deg) and the Sumatran faulting geometry predicts a relative minimum in amplitude for P waves that radiate toward Europe. Nevertheless, the 2004 ground motions dwarf the 1994 motions in both amplitude and duration.  The bottom panels of the graphic show P-wave motion with frequencies f>1Hz. P waves that reflect at Earth's surface tend to lose high-frequency energy, so the duration of high-frequency signal in a seismogram gives a rough indication of the duration of fault rupture.  In contrast to the ~20s of rupture associated with the Northridge earthquake, high-frequency ground motion for the Sumatran earthquake sustains a near constant amplitude for ~500s.  The extreme length of primary shaking makes impossible the visual identification of late-arriving P waves in the Sumatra-event seismogram, in contrast to the set of pulses evident in the Northridge record.  unlike the distinct short  near constant amplitude.  Credits: Jeffrey Park, Yale University

[Southack]

Here's the portion of the Chinese seismic graph (morning of Nov 26, 2005) that is in question:

[investigateworld]

Thanks for the posts. FR is an education.

[Exit148]

I don't have knowledge of the geography there but if it is in a plains or valley area...

This county and city is on the southern bank of the Yangzi, down river and east of that monstrosity of a dam on the Yangzi. The area is surrounded by lakes and mountains. It (JiuJiang) is a modern city, but the epicenter may have been in the boonies. I'm just guessing at that -- if the loss of life estimate is correct, The area is a place that had levees and has its own dam, which has collapsed before. Supposedly it was poorly constructed.

[Alia]

You did superb digging. Thank you.