Javascript must be enabled for this website to display and function correctly.

Larger earthquakes occur less frequently than smaller ones. The relationship is exponential, ie there are ten times as many magnitude 4 or larger earthquakes in a given time period than magnitude 5 or larger earthquakes. This can be expressed by the Gutenberg-Richter formula

log N = a - b M

where *N* is the number of earthquakes per year exceeding a given
magnitude *M*. The constant a reflects the absolute level of seismicity
in an area, and the value of b has generally been found to be
consistently close to 1.0.

The graph shows the relationship for the UK. A least-squares regression to this data gives the relationship

log N = 3.82 - 1.03 M

Also shown is an alternative doubly-truncated exponential model which gives a curved fit ot the data at the higher magnitude end.

On average, the UK may expect:

- an earthquake of 3.7 ML or larger every 1 year
- an earthquake of 4.7 ML or larger every 10 years
- an earthquake of 5.6 ML or larger every 100 years.

Latest News

- BGS have published a report on the earthquake activity in Surrey in 2018
- FAQ on Seismicity at Preston New Road
- Seismicity at Preston New Road, October 2018
- New research shows how submarine optical fibre cables can be used to detect earthquake activity under the seafloor
- Magnitude 4.6 ML Earthquake South Wales 17/02/2018