2008 Lincolnshire earthquake

The 2008 Lincolnshire earthquake was caused by the sudden rupture and motion along a strike-slip fault, 18.6 kilometres (12 mi) beneath Lincolnshire.¹ Earthquake motion occurred over a time span of ~2 minutes but it was most intense and was felt at the surface for just 10 to 30 seconds; maximum vertical ground motion at the epicentre of the earthquake was only ~1 mm. Computer calculations carried out by the BGS infer sinistral motion on a N-S or dextral motion on a E-W orientated strike-slip fault. The nine aftershocks observed, ~5 kilometres (3 mi) SSW of the main earthquake event, point to an approx. N-S orientated fault.¹ From the 5.2 ML magnitude of the main earthquake, a motion of a few centimetres along a ~2.5 kilometres (2 mi) long fault rupture is derived.⁶ The energy released was 3.98×10¹² joules (equal to the detonation of ~950 tonnes of TNT).⁷

Unlike typical earthquakes worldwide, the earthquakes of Northern Europe are intraplate earthquakes, meaning they are not close to tectonic plate boundaries.⁸ Most intraplate earthquakes in Northern Europe (and the UK) are thought to be driven by distant tectonic stresses - a combination of E-W North Atlantic Ridge and N-S African Plate regional stress fields, and local mantle conditions.⁹¹⁰ Indeed, the motion on the strike-slip fault responsible for 2008 Lincolnshire earthquake is compatible with a local NW-SE stress field;¹ a product of the E-W and N-S regional stress fields.

Only a minority of earthquakes in the UK are related to post-glacial rebound e.g. the minor earthquakes (<3.5 ML) of western Scotland, where glaciers ~1 km thick existed during the peak of the last Ice Age.¹⁰

Impact

The earthquake resulted in structural damage to many homes and businesses in the epicentral area.¹⁴ Buildings as large as apartment blocks were reported to have shaken for up to 30 seconds afterwards.² Birds and pets became highly agitated.¹¹ There were no deaths, but a 19 year old man in Wombwell, Barnsley, South Yorkshire suffered a broken pelvis when a piece of chimney fell through the roof onto his attic bed,⁴¹² The earthquake was felt by people as far south as Hampshire, where it was felt as a mild but noticeable vibration, and as far away as Bangor, Northern Ireland where it woke people.¹¹⁴ Police in the Midlands received more than 5,000 telephone calls in an hour from members of the public regarding the earthquake.² The earthquake caused power cuts in some areas.² A church in March, Cambridgeshire reported that since the earthquake, water was coming up from the ground into the cellar at a rate of 10 imperial gallons (45 l) per hour. The water is being analysed to find out if it comes from a water main or a natural spring.¹³ The St Mary Magdalene church at Waltham on the Wolds in Leicestershire had its spire damaged and will be rebuilt at a cost of £100,000.^{citation needed}

Magnitude

The British Geological Survey gave the earthquake a reading of 5.2 on the Richter scale, while the United States Geological Survey reported it measured 4.8M_b.¹⁴ The French Atomic Energy Commission estimated the magnitude was 5.4 on the Richter scale.¹⁵

Aftershocks

A total of nine aftershocks were recorded. The largest, measuring 2.8 on the Richter scale, occurred around five weeks after the initial event, on April 5 at 13:57 GMT. ¹⁶

Significance

It was the largest earthquake in the UK since the 1984 Lleyn Peninsula earthquake, which was magnitude 5.4 on the richer scale. The BGS described the earthquake as an "extremely large earthquake in UK terms but not large in world terms".² Approximately 200 earthquakes occur in the UK every year, approximately 175 of which are small enough not to be noticed by humans. ¹

Contents

Cause

Impact

Magnitude

Aftershocks

Significance

See also

References

External links