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Technically known as an earthquake swarm, the Manchester earthquakes began on October 19th 2002, although the largest one was on October 21st, 2002 (measuring 3.9 on the Ricter Scale and rating as a 5+ on the European Macroseismic Scale (EMS) intensity scale). Earthquakes on this scale are rare in the UK, as the country is not situated on any major faultlines.

Earthquake swarms are sequences of earthquakes clustered in time and space without a clear distinction of main shock and aftershocks. Examples of such swarm activity in the UK are Comrie (1788-1801, 1839-46), Glenalmond (1970-72), Doune (1997) and Blackford (1997-98, 2000-01) in central Scotland, Constantine (1981, 1986, 1992-4) in Cornwall, and Johnstonbridge (mid1980s) and Dumfries (1991,1999) in the Borders.

The Manchester sequence appears to be an earthquake swarm, since the difference in magnitude between the largest event in the sequence and the other events is not as significant as expected in a main shock – aftershock sequence. However, most of the energy during the sequence was actually released in the double-event on October 21 at 11:42. The clustering of these events in time and space does suggest that there is a causal relationship between the events of the sequence.

As a result of this (still ongoing) Manchester swarm, the British Geological Survey (BGS) have stationed three temporary seismograph stations within the city to compliment the two existing stations in the east and south-east. The temporary stations are located in Altrincham, one near Chaddington and one at Manchester University.

These stations have shown that the epicentres of each earthquake varies. The vast majority are located within a wide band running from the city centre out toward Ashton-Under-Lyne and from Gorton in the south to Collyhurst in the north.

Details of the swarm - as of 19 November 2002 (times in GMT).

Year Mo Dy   Hr Mn Secs   Lat      Lon      kmE     kmN     Depth  Mag  Int(EMS)
2002 11 19   02 31 45.3   53.486  -2.208    386.2   398.8     5.0  1.7             

2002 11 19   01 00 31.0   53.491  -2.188    387.5   399.4     5.0  2.1  2+   

2002 11 16   07 34 36.9   53.501  -2.205    386.4   400.5     5.0  2.1             

2002 11 16   04 59  1.9   53.484  -2.179    388.1   398.6     5.0  2.5  3+   

2002 11 16   04 57 46.7   53.490  -2.166    389.0   399.3     5.0  2.1  2+  

2002 11 13   00 19 58.5   53.488  -2.201    386.7   399.1     5.0  1.6             

2002 11 11   22 21 12.7   53.484  -2.162    389.3   398.6     5.0  1.8             

2002 11 10   18 47  9.5   53.491  -2.222    385.3   399.4     5.0  2.0            

2002 11 10   11 43 54.7   53.482  -2.172    388.6   398.4     5.0  2.0             

2002 11 10   04 12 22.6   53.491  -2.222    385.3   399.4     5.0  2.3  3+  

2002 11 09   23 36 42.7   53.481  -2.158    389.5   398.3     5.0  2.0             

2002 11 09   01 54 33.2   53.480  -2.164    389.2   398.2     5.0  2.2  2+

2002 11 09   01 11 20.1   53.474  -2.167    388.9   397.5     5.0  2.1             

2002 11 09   00 27 43.7   53.485  -2.137    390.9   398.7     5.0  1.9             

2002 11 09   00 21  7.3   53.487  -2.178    388.2   398.9     5.0  1.7             

2002 11 06   04 37 43.8   53.478  -2.107    392.9   398.0     5.0  1.7             

2002 11 06   03 32 22.7   53.490  -2.101    393.3   399.3     5.0  1.8             

2002 11 06   02 45 52.0   53.495  -2.175    388.4   399.9     5.0  1.6            

2002 11 06   02 34 38.9   53.499  -2.082    394.6   400.2     5.0  1.7            

2002 11 05   20 31 23.5   53.477  -2.163    389.2   397.9     5.0  1.9             

2002 11 04   07 32 32.0   53.474  -2.159    389.5   397.6     5.0  2.7  3+ 

2002 11 04   07 29 12.8   53.481  -2.168    388.8   398.3     5.0  2.3  2+   

2002 11 04   01 44 15.5   53.499  -2.165    389.0   400.2     5.0  1.1             

2002 11 01   04 22 52.7   53.487  -2.217    385.6   399.0     5.0  1.5             

2002 10 31   01 50 57.4   53.484  -2.211    386.0   398.6     5.7  2.3  2+  

2002 10 31   00 07 15.0   53.469  -2.127    391.6   396.9     4.3  1.9             

2002 10 29   17 32 15.9   53.487  -2.209    386.1   398.9     5.0  2.4  3+ 

2002 10 29   04 59 57.2   53.493  -2.212    386.0   399.7     5.0  1.6             

2002 10 29   04 43 59.1   53.506  -2.178    388.2   401.1     5.0  1.8             

2002 10 29   04 42 52.0   53.481  -2.198    386.9   398.3     5.0  2.6  3+

2002 10 29   00 07 53.7   53.486  -2.198    386.9   398.8     5.0  2.2  3+ 

2002 10 28   19 25 59.1   53.483  -2.201    386.7   398.6     5.0  2.3  3+

2002 10 28   03 27 51.1   53.494  -2.109    392.7   399.7     5.0  1.7            

2002 10 28   03 08 14.1   53.494  -2.190    387.4   399.7     5.0  2.0             

2002 10 26   22 35 35.5   53.504  -2.188    387.5   400.8     5.0  1.6            

2002 10 26   21 14 26.6   53.492  -2.179    388.1   399.5     5.0  1.9             

2002 10 25   17 24 48.1   53.485  -2.197    387.0   398.8     2.5  2.6  3+  

2002 10 25   04 26 15.4   53.518  -2.250    383.4   402.4     5.0  1.6             

2002 10 25   00 38 31.1   53.492  -2.121    392.0   399.5     5.0  1.6             

2002 10 25   00 25 44.7   53.485  -2.212    385.9   398.8     5.0  2.3  2+   

2002 10 25   00 20 39.7   53.488  -2.213    385.9   399.1     5.0  2.5  3+  

2002 10 25   00 19 27.3   53.481  -2.204    386.5   398.4     5.0  2.5  3+   

2002 10 25   00 02 51.0   53.505  -2.173    388.5   401.0     5.0  1.6           

2002 10 24   23 07 51.6   53.496  -2.210    386.1   399.9     5.0  2.2          

2002 10 24   19 13 18.6   53.482  -2.139    390.8   398.4     5.0  1.9          

2002 10 24   19 00 45.8   53.489  -2.202    386.6   399.2     5.0  2.2  3+  

2002 10 24   18 37 12.6   53.487  -2.213    385.9   399.0     5.0  2.6  3+  

2002 10 24   16 34 38.8   53.493  -2.188    387.5   399.6     5.0  2.2            

2002 10 24   15 46 44.2   53.482  -2.197    386.9   398.4     5.0  2.8  3+  

2002 10 24   15 33 49.4   53.512  -2.229    384.8   401.8     5.0  1.9             

2002 10 24   15 00  9.9   53.494  -2.206    386.3   399.8     5.0  1.8             

2002 10 24   14 56 40.7   53.496  -2.194    387.2   400.0     5.0  2.1             

2002 10 24   14 55 55.7   53.497  -2.201    386.7   400.1     5.0  1.9             

2002 10 24   14 29 26.1   53.456  -2.182    387.9   395.5     5.0  1.7  2+   

2002 10 24   12 20 28.4   53.495  -2.140    390.7   399.9     5.0  1.6             

2002 10 24   10 45 13.9   53.480  -2.172    388.6   398.2     5.0  1.8             

2002 10 24   10 26 55.8   53.490  -2.152    389.9   399.3     5.0  1.9             

2002 10 24   09 46 54.6   53.492  -2.134    391.1   399.6     5.0  1.9             

2002 10 24   09 36  5.5   53.493  -2.136    391.0   399.7     5.0  1.7             

2002 10 24   09 18  5.1   53.503  -2.140    390.7   400.8     5.0  1.8             

2002 10 24   08 42 36.7   53.499  -2.153    389.8   400.3     5.0  1.9             

2002 10 24   08 24 54.7   53.485  -2.179    388.1   398.7     3.7  3.1  4+   

2002 10 24   08 21 44.7   53.490  -2.180    388.1   399.3     5.0  2.0             

2002 10 24   07 52 54.4   53.480  -2.173    388.5   398.2     5.0  2.6  3+   

2002 10 24   06 38 26.5   53.473  -2.150    390.0   397.4     5.0  1.7             

2002 10 24   05 53 54.5   53.482  -2.200    386.8   398.4     5.0  2.2             

2002 10 24   04 38 36.9   53.479  -2.148    390.2   398.0     5.0  2.0  2+ 

2002 10 24   04 36 59.1   53.470  -2.161    389.3   397.1     5.0  2.3             

2002 10 23   23 27 25.4   53.485  -2.174    388.4   398.8     5.0  1.9             

2002 10 23   20 31 28.8   53.484  -2.172    388.6   398.6     5.0  2.5  3+   

2002 10 23   20 20 56.7   53.499  -2.214    385.8   400.3     5.0  1.8             

2002 10 23   20 16 31.7   53.477  -2.162    389.2   397.8     5.0  2.2  3+   

2002 10 23   19 18 11.6   53.488  -2.164    389.2   399.1     5.0  2.0             

2002 10 23   06 27 52.6   53.498  -2.137    390.9   400.2     5.0  2.0             

2002 10 23   05 44 34.8   53.475  -2.125    391.7   397.6     3.6  1.9  2+   

2002 10 23   04 46 21.1   53.514  -2.211    386.0   402.0     5.0  1.6             

2002 10 23   03 57 47.6   53.493  -2.051    396.6   399.6     5.0  1.6             

2002 10 23   01 53 28.8   53.477  -2.157    389.6   397.9     5.0  2.8  3+   

2002 10 22   16 53 41.0   53.488  -2.145    390.4   399.1     5.0  2.4  2+   

2002 10 22   13 38 27.9   53.491  -2.188    387.5   399.4     5.0  1.9             

2002 10 22   12 51 59.6   53.468  -2.095    393.7   396.9     5.0  1.4            

2002 10 22   12 28  8.4   53.473  -2.146    390.3   397.4     4.2  3.1  4+ 

2002 10 22   09 47  2.3   53.480  -2.147    390.3   398.2     5.0  1.7             

2002 10 22   06 27 24.7   53.491  -2.079    394.8   399.4     5.0  1.7             

2002 10 22   06 20 57.5   53.483  -2.202    386.6   398.6     5.0  2.0             

2002 10 22   04 27 19.0   53.481  -2.133    391.2   398.3     5.0  1.3             

2002 10 22   04 08 51.9   53.492  -2.121    392.0   399.5     5.0  1.5  2+   

2002 10 22   04 02 45.9   53.484  -2.198    386.8   398.7     5.0  1.8             

2002 10 22   03 54  2.4   53.464  -2.154    389.8   396.3     5.0  2.0  2+   

2002 10 22   03 39 37.6   53.463  -2.219    385.5   396.3     5.0  2.9  4+   

2002 10 22   00 41 49.9   53.502  -2.118    392.2   400.6     5.0  1.6             

2002 10 22   00 24 22.0   53.471  -2.170    388.7   397.2     5.0  1.6             

2002 10 21   22 34 38.3   53.472  -2.183    387.9   397.3     5.0  2.1             

2002 10 21   17 02 42.1   53.502  -2.211    386.0   400.6     5.0  2.2             

2002 10 21   16 22 21.8   53.480  -2.193    387.2   398.2     5.0  2.0             

2002 10 21   11 56 46.0   53.441  -2.139    390.8   393.8     5.0  2.0             

2002 10 21   11 42 56.9   53.478  -2.218    385.5   397.9     5.0  3.5  4+ 

2002 10 21   11 42 34.7   53.478  -2.196    387.0   398.0     2.8  3.9  5+   

2002 10 21   11 15  6.6   53.490  -2.155    389.7   399.3     5.0  1.8             

2002 10 21   08 04 58.7   53.497  -2.210    386.1   400.1     5.0  2.3  3+  

2002 10 21   07 45 15.8   53.475  -2.196    387.0   397.6     5.0  3.2  4+   

2002 10 21   07 29 20.4   53.490  -2.198    386.9   399.3     5.0  1.8            

2002 10 19   01 44 59.5   53.504  -2.186    387.7   400.9     5.0  1.4             

2002 10 19   01 21 26.6   53.506  -2.203    386.5   401.1     5.0  1.4             

Key to the table.

Year Mo Dy - Year, month and day of event.
Hr Mn Secs - Time of occurrence of event in hours, mins and secs. All times are in Greenwich Mean Time.
Lat - Latitude of the event, positive latitude indicates north.
Lon - Longitude of the event, negative longitude indicates west.
kmE - UK National Grid Reference in kilometres east of grid origin.
kmN - UK National Grid Reference in kilometres north of grid origin.
Dep - Depth of the hypocentre in kilometres.
Mag - Richter local magnitude of the event.
Int - Maximum EMS intensity. 2+ indicates felt, no macroseismic details. 3+, 4+ etc indicates felt at 3 or 4, but no survey carried out. 3, 4, 5 etc describes the maximum EMS intensity produced by the event.

Source : http://www.quakes.bgs.ac.uk

I will update this node with further details of the earthquake swarm as and when necessary.

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