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A fallen chimney in Dudley.
23 September 2000 and another near Shock waves
Melton Mowbray in October 2001 from the Dudley
stirred
(magnitude 4.1) were felt over much of earthquake were
England and Wales. Many people recorded across the
reported ornaments, pictures or toys UK on the BGS
falling or moving. A few also reported seismic monitoring
heavy objects moving, including washing network and
machines, cookers and lounge furniture, throughout Europe.
but no one reported any damage. This was the largest
Last autumn people in Britain kept getting woken up by UK earthquake
earthquakes, but it’s nothing out of the ordinary, writes Alice Walker. The Dudley earthquake
The earthquake centred on Dudley, West
since one measuring
5.1 near Shrewsbury in 1990. That one sensation of being disoriented’ and ‘I
Midlands, on 23 September 2002, was caused some damage near its epicentre could feel the ground shaking below my
the third large earthquake to strike and was felt throughout England and feet. Desks in the classroom were
World earthquakes reports. TV images showed the extent of central England in two years. With a Wales. vibrating as well’. These indicate that the
Earthquakes occur anywhere in the the school’s destruction and the minimal magnitude of 4.8, it was 8-11 times To put the Dudley earthquake into maximum intensity experienced was 5
world, although most occur along the damage elsewhere, clearly revealing poor bigger in energy than the previous two. It perspective: 1,300 of this size or bigger EMS (European Macroseismic Scale).
edges of the great plates that make up the construction and a tragedy which should woke up people from Dublin to the east occur each year somewhere in the world. Immediately after the first earthquakes
Earth’s outer skin and which move at never have happened. coast of England and from Yorkshire to However, in the UK we expect, on that people actually felt, we installed
about the speed our fingernails grow. Devon and the south coast. At the average, an earthquake of this size or three temporary seismometers in the
Each year the globe is shaken by about UK earthquakes epicentre, there was much alarm and bigger once every eight years. This doesn’t epicentral region to more accurately
800 ‘moderate’ earthquakes, (magnitude The UK is not immune from some damage to chimneys and roofs, mean it will be another eight years before measure the quakes’ depths. They turned
5-5.9 on the Richter scale), 120 ‘strong’ earthquakes. There are around 200 each with plaster cracking on interior walls, the next large one. Statistics don’t work out to be between 2-4km deep – one of
ones (magnitude 6-6.9) and around 20 year, but people only notice about 20 of indicating a maximum intensity of 6 on like that. The next 4.8 magnitude the shallowest sequences in the UK.
‘major’ earthquakes of magnitude 7 or these. The largest, in 1931, had a the European Macroseismic Scale (which earthquake could occur tomorrow, next Reports of quakes had died down by the
greater. There are many more smaller magnitude of 6.1. Fortunately it centred describes the degree of shaking in an year or next century. Seismologists have end of November.
ones, some 70,000 in 2001, but most on Dogger Bank, 100km out in the earthquake). BGS received some 8,000 not yet solved the problem of predicting
Alice Walker. went unnoticed except by the North Sea, and caused only minor responses to earthquakes, but as The UK seismic network
seismologists who study them. damage on the east coast of England. The BGS network of 146 seismometer
‘
questionnaires more objective data
Larger earthquakes can cause
landslides, tsunamis and even the ground
Onshore, the largest earthquake in the
last 140 years occurred in North Wales
which we The BGS network of is collected they are stations monitors earthquakes around the
world and in the UK. Data is transferred
distributed constantly
to turn to liquid. They can rupture gas or on 19 July 1984 with a magnitude of nationwide through 146 seismometers improving their to Edinburgh four times a day (or on
water mains, causing raging fires, and 5.4. It was felt over most of England, the media and assessments of how demand during particularly interesting
access for emergency services may be throughout Wales and even into Scotland internet. Typical
monitor earthquakes likely earthquakes periods) via phone lines or the internet.
blocked. The great fire in San Francisco and Ireland. It caused damage as far as
’
We can determine the location,
following the 1906 earthquake lasted Liverpool, 120km from its epicentre.
reports included: ‘I
woke up frightened
around the world. are, and can inform
engineers and magnitude and nature of an event
three days and was more damaging than More recently, an earthquake with a and clinging to my planners (earthquake, explosion, sonic boom, or
the shaking itself. Firestorms after the magnitude of 4.2 near Warwick on bed! I thought the roof was going to accordingly. mining-induced seismicity) within two
1923 Tokyo earthquake killed over come down on me;’ ‘I was sitting at my BGS continually updates details of hours, and widely disseminate the results.
38,000 people. In January 2001 computer when the whole house started British and important earthquakes across Government, industry, academia, the
‘ The UK is not
immune from
earthquakes in El Salvador and India
(both magnitude 7.7) killed 800 and
to shake violently. I could see walls and
ceiling moving, also kitchen wall
the world on its seismology website. The
website received 360,000 hits on the day
media and the public are often intensely
interested. Our 24-hour on-call service,
P l a n e t E a r t h S p r i n g 2 0 0 3 — w w w. n e r c . a c . u k
20,000 people respectively.
P l a n e t E a r t h S p r i n g 2 0 0 3 — w w w. n e r c . a c . u k
cupboards. My computer screen was of the Dudley earthquake! with computer connections between staff
The Italian earthquake on 31 shaking and I could feel the floor heaving homes and the BGS Edinburgh office,
earthquakes.
’
October 2002, which killed 26 beneath me;’ ‘I was asleep and the whole The Manchester earthquakes allows rapid analysis. For more
schoolchildren and teachers, registered house (on top of a hill) shook for over 10 Most recently, there has been a sequence information visit
only 5.6 on the Richter scale; about 270 seconds. There was a deep disturbing of earthquakes around Manchester. In the www.earthquakes.bgs.ac.uk.
quakes of this size or greater happen each rumbling/rattling noise all around me five weeks following the strongest shock
year, worldwide. At the British Geological and I felt I was lying on top of a large of 3.9 on 21 October 2002, we located
Survey (BGS), we realised within an hour oscillating jelly structure.’ These some 106 earthquakes, with magnitudes
or so (as soon as the magnitude was descriptions are typical for larger UK between 1.1-3.9, with people reporting
calculated) that this earthquake was too earthquakes and for the epicentral areas feeling 36 of them. There was no
small to bring down any well-constructed Alice Walker is Head of Earthquake
of some smaller ones. So far, two people significant damage. Most reports came Seismology at the British Geological
building, as was suggested in early have reported injuring themselves as they from greater Manchester, with a number Survey, Murchison House, West Mains
rushed out of the house – one broke their from up to 30km away for the largest Road, Edinburgh, EH9 3LA, tel: 0131
Epicentres of earthquakes with magnitudes 1.5ML
leg falling down stairs, another broke a quake. Typical reports were: ‘The whole 650 0202, email: a.b.walker@bgs.ac.uk
or greater, from 1980 to 2002. toe. building wobbled and shook producing a
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