BS: Earthquakes in Manchester, UK.

Subject: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 21 Oct 02 - 08:52 AM

Well, I'll be! Just had our second earth tremor in 4 hours! 1st one was a 3.5 at 8:50 last one felt a lot stronger at 12:45. Being on the 10th floor made it a bit scary. So I did the only thing possible in the circumstances...

Went to Sainsbury's to buy lunch. Building was still standing when I got back so I am here again. Hope it doesn't happen again. I might have to go to Asda next time:-)

No reported injuries or damage as yet I'm glad to say.

Cheers

Dave the Gnome

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Mr Red
Date: 21 Oct 02 - 09:32 AM

the BBC are under reporting you at 2.8.
About time the city had a good shake-up. sort of Grater Manchester.
I'll get my coat...........

Subject: RE: BS: Earthquakes in Manchester, UK.
From: MudGuard
Date: 21 Oct 02 - 09:47 AM

Did you check wether it was not just a fart produced by our 'spaw? ;-)

Glad noone got hurt...

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 21 Oct 02 - 09:54 AM

Typical BBC. If it ain't in London it must be insignificant...

I agree about the shake up. Sort of as-salts the senses. But I think your pun on greater is a bit cheesy;-)

Do you need a hat as well?

Hehehehehe (That 'quake must have unhinged me)

Cheers

DtG

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Mad4Mud
Date: 21 Oct 02 - 11:49 AM

Welcome to my world!

xoxox,
Mad4Mud in Southern California

Subject: RE: BS: Earthquakes in Manchester, UK.
From: DMcG
Date: 21 Oct 02 - 11:55 AM

This our third earthquake recently. Isn't time we were told officially that there is no need to panic?

Subject: RE: BS: Earthquakes in Manchester, UK.
From: 8_Pints
Date: 21 Oct 02 - 02:46 PM

Sue & son were in the kitchen on the ground floor and felt nothing ..

.. I was in study, also on the ground floor and felt a distinct swaying of the house for 2 seconds.

Strange how the civic cameras caught the lunch-time event, yet no-one in the streets seemed to recognise it, much less react in any way!

Anyway this must be small fry compared to incidents on the boundaries of the tectonic plates.

Glad no-one hurt.

Bob vG

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Ed.
Date: 21 Oct 02 - 03:33 PM

It seemed very localised. Driving to work in Stockport, I didn't notice the first one, and only noticed a small shudder for the 12:40 one.

My girlfriend, who works in central Manchester, thought that the second was much worse than the Dudley one.

Ed

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Harry Basnett
Date: 21 Oct 02 - 03:49 PM

Sara and me were shaken and a little bit stirred........

Hope you enjoyed yourselves yesterday, Bob and Sue........

All the best...........Harry.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Murray MacLeod
Date: 22 Oct 02 - 01:37 AM

I once read somewhere (or maybe a man in a pub told me) that every earthquake, anywhere, anytime, is followed by an equal and opposite reaction on the opposite side of the globe, within hours (or maybe it was days)

Is there any truth in this? And if true, where would the global opposite of Manchester be ?

Murray

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,Skarpi at work.
Date: 22 Oct 02 - 03:24 AM

Halló all, welcome to my world to......
we have this every week all teh year around Iceland.
Some are small and other are stronger just yesterday we
had some earthquakes in the Glacier Vatnajökull so we might
have some eruption? we don´t know yet.
Hope you are all right, All the best Skarpi Iceland.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 22 Oct 02 - 11:45 AM

We are now up to 13 in the last 24 hours ranging from 2 to 3.9 - and more expected! Perhaps we should be renamed from the rainy city to the wobly city;-)

Cheers

DtG

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,Penny S. (elsewhere)
Date: 22 Oct 02 - 11:53 AM

Here be diagrams

about halfway down the document showing how earthquake waves are refracted through the Earth.

There is a hypothesis in planetary geology about large impacts on one sid of a body being focussed at the other side and causing disruptions. This is based on observing the position of large craters and features on their antipodes. I don't think the Manchester quakes are in that class.

Penny

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,Penny S. (elsewhere)
Date: 22 Oct 02 - 11:55 AM

13! That's interesting (in the Chinese sense). I knew there had been more today, but not that many. I don't think there has been any vulcanism in the area for some time (geological, that is)....

Penny

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,Penny S. (elsewhere)
Date: 22 Oct 02 - 12:09 PM

Shaking site

This makes it 18 now.

Penny

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 22 Oct 02 - 12:39 PM

I'm expecting Rivington Pike to erupt any moment...

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Mr Red
Date: 23 Oct 02 - 08:28 AM

The other side of the world to Manchester? Culturally? Where shall we start.......

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Fingerbuster
Date: 23 Oct 02 - 08:46 AM

I live in Bury but i didn't feel a thing! Good stuff that Stella.


;-}

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 23 Oct 02 - 12:45 PM

Latest count according to the Manchester Evening News is 21 with more due over the next few days. We are in the middle of what the experts call an 'earthquake swarm'. This is a series of small but numerous earthquakes and is quite unique in a built up area in the UK. So, another Manchester claim to fame.

United, Oasis, Earthquakes, what next?

Cheers

DtG

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Ed.
Date: 23 Oct 02 - 01:27 PM

What next?

The Biggest University

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,stringman
Date: 23 Oct 02 - 01:40 PM

Can we not beleve, this might be an undergound explosion,or I am just a litte bit or line.!!

AS In nuke testing. Just a thought.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Catherine Jayne
Date: 23 Oct 02 - 01:49 PM

Dave......you will have to stop eating curry!!!!

Glad everyone is ok.

Take care Gnome of Wobbly city!!

Cat

Subject: RE: BS: Earthquakes in Manchester, UK.
From: HuwG
Date: 23 Oct 02 - 02:16 PM

No, no, if they were going to test nuclear weapons anywhere near Manchester, it would be a benefit to mankind if they did it above ground.

There is a clear difference on seismographic traces between earthquakes and underground nuclear explosions (given enough monitoring stations). The first shock waves to arrive at a seismograph are the "p-waves". In the case of a nuclear explosion, the leading wave of these is always a compressive event; for earthquakes, the leading wave arriving at a monitor which is in a plane aligned with the fault movement, is a tensional event (or to put it another way, the first wave to arrive, sucks).

There are a number of faults trending Northwest to Southeast in the solid rocks underlying the alluvium and glacial crud on which Manchester is built. As of last night, the various epicentres did not pinpoint movement on any one of these faults (although the Pendleton Fault underneath Salford and Stockport appeared to be the prime suspect). This would indicate that the fault system is behaving as a broad shear zone, and small movements are occuring on all, or more than one, of these NW - SE faults (which also suggests that the shocks will go on for some time).

Geographically, the opposite side of the world to Manchester is a spot northeast of Fiji. Murray Macleod, your man in the pub may have been referring to the sort of events which produced "Weird Terrain", on Mercury (I think) and some of the moons in the Solar System. These are concentric ridges and valleys surrounding the opposite point to a big impact crater. A big enough impact sends surface waves, particularly Gr (or Ground Roll), with absolutely huge amplitude, radiating from the point of impact, and when they arrive at the far side, they become intensely focussed and reinforce each other, causing the lasting terrain effects. The impact needed to do this is enormous. Because the earth's surface is made of zones with all sorts of different compositions and densities, the Ground waves from ordinary earthquakes become attenuated and refracted, and this sort of concentration at the far side doesn't happen. Sorry.

The last earthquake I remember being jolted by in Glossop (about 12 miles east of Machester City Centre) was thirteen or fourteen years ago, and was caused by collapsing (long-abandoned) mine workings in Dukinfield, in East Manchester, about 6 miles from Glossop. That was apparently quite as intense as those which have taken place recently. I haven't felt any of these latest shocks, though most have occurred while I am at work in Buxton, some 25 miles from Manchester.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 24 Oct 02 - 04:30 AM

In the office - 10th floor just bounced away quite happily!

27 and counting...

Subject: RE: BS: Earthquakes in Manchester, UK.
From: GUEST,stringman.
Date: 24 Oct 02 - 05:19 AM

OK, clever dick. HumG. so i got it a bit wrong. Mmmmmmmmmmmmmmmm

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Dave the Gnome
Date: 24 Oct 02 - 05:54 AM

And I have just heard that the Carrington Spur off the M60 has been closed due to quake damage. Or so we are told. If I was to suggest, as this road is miles from the epicentre, it is more likely to be poor materials and bad building would I be being cynical?

Cheers

DtG

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Alio
Date: 24 Oct 02 - 06:29 AM

My son works in the centre of Manchester on the 11th floor, and he said it was a bit scary. He also did the only thing possible (no, he didn't pop into Sainsbury's) - he went for a drink! Obviously takes after his mum.
Ali

Subject: RE: BS: Earthquakes in Manchester, UK.
From: greg stephens
Date: 24 Oct 02 - 08:13 AM

The Lord is destroying the city, because Boddingtons is moving to Wales and there are gay people living in loft apartments. Let the righteous flee while there is still time.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: HuwG
Date: 24 Oct 02 - 08:44 AM

Some results of a Google search on Mercury + Weird Terrain are here

Although this seems to refer to the "equal and opposite" effect which Murray Macleod's taproom expert was talking about, it is produced only by cataclysmic events.

I refer you to the diagrams in GUEST, Penny S (elsewhere)'s post. You can see that only rather attenuated p-waves make it to the far side, s-waves (which are pretty feeble events anyway) don't get there at all. The Ground Waves (Gs and Gr) which do all the damage are not discussed in that site.

p-waves and s-waves, while not damaging, are vital tools in the examination of the earth's interior; have a look at this site. p-waves are often noticeable on the surface; I am told that they feel like a single sharp blow. At which point, savvy Californians who are outdoors, move as far as they can in the next ten seconds, to where debris is unlikely to fall on them when the Ground Shake and Ground Roll arrive.

Please shut me up somebody; as I have very little direct experience of the phenomenon compared with Californian 'Catters (and those in Greece, Turkey, Iran, the Middle East generally, Chile, Northern India or Pakistan etc), I am probably talking grade 'A', 100% taurine waste product.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: radriano
Date: 24 Oct 02 - 02:24 PM

I'm in San Francisco in northern California, where we are quite familiar with earthquakes. I work for the California Geological Survey - our website may provide useful information about earthquakes.

Subject: RE: BS: Earthquakes in Manchester, UK.
From: radriano
Date: 25 Oct 02 - 02:39 PM

The U.S. Geological Survey (the Federal survey) tracks earthquakes worldwide on a daily basis. Click on the link below to see their latest information.

US Geological Survey

Subject: RE: BS: Earthquakes in Manchester, UK.
From: allanwill
Date: 25 Oct 02 - 05:23 PM

DtG

In response to one of your earlier postings:

There is no need to panic



but there probably will be!

Allan

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Murray MacLeod
Date: 25 Oct 02 - 06:01 PM

Thank you , Penny, and HuwG.

I sometimes have the sneaking suspicion that people who impart information in pubs may on occasion not have a total grasp of the facts ....

Murray

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Penny S.
Date: 27 Oct 02 - 02:10 PM

Here's the local university take on the swarm.

Manchester Earth Sciences

Penny

Subject: RE: BS: Earthquakes in Manchester, UK.
From: Bassic
Date: 27 Oct 02 - 08:26 PM

Comment from Gerald Kaufman, UK politician, when a guest on Have I Got News For You, satirical News Quiz on the BBC. He reported that as a consequence of the `quakes, the only joke ever to have come out of Manchester "Town Hall" was a new slogan for the city, MANCHESTER, A CITY ON THE MOOVE!!