GeoIndex help | Hazards map theme

View the Hazards map theme

Click on the links below for further information about the available datasets.

Earthquake Seismology (modern and historical recordings)

The British Geological Survey (BGS) has been charged with the task of operating and further developing a uniform network of seismograph stations throughout the UK in order to acquire standardised data on a long-term basis. The project is supported by a group of organisations under the chairmanship of the Office for the Deputy Prime Minister (ODPM formerly known as DTLR) with major financial input from the Natural Environment Research Council (NERC). The aims of the BGS Seismic Monitoring and Information Service are to develop and maintain a national database of seismic activity in the UK for use in seismic hazard assessment, and to provide near-immediate responses to the occurrence, or reported occurrence, of significant events to its customers and sponsors. A 24-hr on-call service is maintained for this purpose. Almost every week, seismic events are reported to be felt somewhere in the UK. A number of these prove to be sonic booms or are otherwise spurious, but a large proportion are natural or mining?induced earthquakes often felt at intensities which cause concern and, occasionally, some damage. In an average year, some 200 earthquakes are detected and located by BGS with around 15% being felt by people.

Within the 146-station, high sensitivity monitoring network, 18 strong motion instruments have been integrated. Data from all sensors is available for analysis and interpretation by BGS scientists in Edinburgh, in near real time, through radio and telephone links. The high sensitivity network has been expanded to cover the whole country since the 1970's and achieves a detection threshold for magnitude 2.0 earthquakes throughout the land area even in high noise conditions. All earthquakes of magnitude 2.5 and above have been captured since 1979. For more information about earthquakes, visit www.earthquakes.bgs.ac.uk.

Notes on the completeness of the historical and Instrumental Datasets

The historical catalogue has been compiled, in general, from macroseismic observations (ie felt effects). Before 1700, only earthquakes with magnitudes of 4.0 ML or greater are included. After 1700, all known events with magnitudes of 3.0 ML or greater are included together with some other, smaller ones. Accuracies of magnitude, location, and origin time vary with the quality of information available for this period as they do for instrumental measurements in the post 1970 period. In that case, variations are largely a function of the seismograph station coverage, which has been improving up to the present day.

The instrumental catalogue contains all detected earthquakes; however, the completeness improves as the seismograph monitoring networks were expanded over the years. As a guide, the completeness threshold was approximately magnitude 4.0 ML in 1970, improving to 2.5 ML in 1979 for mainland UK.

Landslides

The National Landslides Database holds over 15 000 records of landslides and is the definitive source of landslide information for Great Britain (excludes Northern Ireland, Isle of Man and the Channel Islands).

Geological indicators of flooding

Geological maps show where all the floodplains and coastal plains in Britain are located and therefore the main areas at greatest risk of flooding. The map shows areas vulnerable to two main types of flooding: inland (river floodplains) and coastal/estuarine.

The map is based on observation of the types of geological deposit present and does not take into account any man-made influences such as house building or flood protection schemes. It also does not take into account low-lying areas where flooding could occur but where there are no materials indicating flooding in the geological past.

The BGS Geological indicators of flooding data should be regarded as complementary to, and not a replacement for, existing flood risk maps such as those provided by the Environment Agency.

More information on geological indicators of flooding is available.

A generalised version of the data is shown, visible at map scales above 1:625 000.

More detailed data can be obtained from BGS and site specific information will be available in the near future.

Superficial deposits 1:625 000 scale

The 'Superficial deposits' shown on the GeoIndex map includes the youngest geological deposits laid down in England and Wales, Scotland and part of Northern Ireland. This map is based on the first edition Drift 1:625 000 scale Geological Map of the United Kingdom published in 1977 as two sheets, North and South, available from the BGS Internet Shop.

The Superficial deposits, mainly formed in the Quaternary period of geological time, which extends from the present back to 2 million years ago. Many of the deposits were formed during episodes of glaciation ,or deposited by rivers. They occur as discontinuous patches and larger spreads and rest on top of the older rocks (referred to in the Bedrock).

Most of these Superficial deposits are unconsolidated sediments such as gravel, sand, silt and clay. The name of each deposit or group of deposits corresponds to that shown on the published 1:625 000 map e.g. River Terrace Deposits.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1977. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Faults 1:625 000 scale

Digital geological dataset depicting the faults only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Dykes 1:625 000 scale

Digital geological dataset depicting the dykes only of the bedrock geology of the United Kingdom at surface/rock head.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276

Bedrock 1:625 000 scale

The 'bedrock' shown on the GeoIndex map comprises the bedrock geology, which represents the outcrops (at surface) and subcrops (at near-surface, beneath superficial deposits) in England and Wales, Scotland and part of Northern Ireland. It is based on the third edition Solid 1:625 000 scale Geological Map of the United Kingdom published in 1979 as two sheets, North and South. These sheets are available from the BGS Internet Shop.

CAUTION

The source geological maps originally used to compile the published 1:625 000 maps are 1:50 000 and 1:63 360 (one inch to one mile) scale maps published before 1979. Many of these have since been up-dated and may therefore not now agree with the 1:625 000 geology shown here.

Because of the generalisation and simplification used in the compilation of this map, it should not be used to determine the detailed geology of any specific sites. It is best used to provide a basic understanding of the geology of the country in general, and for showing the geology of large regions where broad trends are more important than specific details.

Persons interested in the detailed geology of particular sites should consult the latest large scale maps or the British Geological Survey at:-

British Geological Survey,
Environmental Science Centre,
Keyworth,
Nottingham NG12 5GG.
Tel: +44 (0)115 936 3143
Fax: +44 (0)115 936 3276