Earthquake Strikes United Kingdom
Largest Tremor in over Twenty Years hits parts of England and Wales
Feb 27, 2008
The British Geological Survey (BGS) report that at 00.56 GMT on 27 February 2008 an earthquake with a magnitude of 5.2 on the Richter Scale was recorded near Market Rasen, Lincolnshire in East Central England.
Seismologist Dr Brian Baptie of the BGS said: “This is a significant earthquake for the UK and will have been widely felt across England and Wales. Although after shocks may occur it is extremely unlikely to be a precursor to a larger earthquake”
Around 200 earthquakes are recorded by the BGS in the UK each year. Approximately 25 of these are felt by people.
Previous Earthquakes in the UK
· April 2007 – Folkestone, Kent (magnitude 4.3)
· December 2006 – Dumfries and Galloway, Scotland (magnitude 3.5)
· September 2002 – Dudley, West Midlands (magnitude 5.0)
· October 2001 – Melton Mowbray, East Midlands (magnitude 4.1)
· September 2000 – Warwick, Warwickshire (magnitude 4.2)
· April 1990 – Bishop’s Castle, Shropshire (magnitude 5.1)
· July 1984 – Nefyn, North Wales (magnitude 5.4)
· June 1931 – In the North Sea near Great Yarmouth (magnitude 6.1)
What Causes An Earthquake?
The Earth is made up of an inner core, outer core, mantle and crust. The crust and upper mantle form a cold, strong layer known as a lithosphere.
The lithosphere is broken into plates and convection currents in the mantle cause the plates to move in different directions with the majority of earthquakes occurring at the plate boundaries.
When plates converge, one plate is drawn slowly beneath the other over a period of thousands of years.
When plates collide, rock layers are forced upwards creating mountains.
Where plates diverge, lava emerges from the mantle and cools to form new sections of crust and these diverging plate boundaries are often found underwater.
Other plates move very slowly alongside each other. Faults are found at the edges of the plates where the crust is moving in different directions. In some places the plates become locked together and potential energy builds.
When the plates give, the stored energy is released in the form of an earthquake. The point of the earthquake’s origin beneath the surface is known as the hypo-centre.
An earthquake emits its power as three waves of energy.
- Primary or P-waves are felt as a sudden jolt.
- Secondary or S-waves arrive a few seconds later and are felt as a more sustained side-to-side shaking.
- Surface waves radiate outward from the epicentre – the point on the surface directly above the hypo-centre - and arrive after the main P and S waves.
There are two types of wave with different movements.
- Rayleigh waves create rolling, up and down movements.
- Love waves (named after the mathematician A.E.H. Love) cause the ground to twist from side to side.
These two types of surface wave cause great damage to buildings.
Summary Of UK Earthquake
DATE : 27 February 2008
ORIGIN TIME : 00.56 GMT
LAT/LONG : 53.39 degrees NORTH / 0.35 degrees WEST
GRID REF : 509.9 kmE / 389.0 kmN
DEPTH : 10.0 km
MAGNITUDE : 5.2 Richter Scale (ML)
LOCALITY : Market Rasen, Lincolnshire
Sources
BBC News
British Geological Survey
