|Date||11 May 2011
|Origin time||16:47 26s UTC
|Lat/Lon||37.65° North / 1.76° West
|Depth||about 3.5 km|
|Locality||66 km SW Murcia, a few km from Lorca|
The earthquake in Spain that occurred on 11 May 2011 appears to be the latest in a series of earthquakes occuring along the Alhama de Murcia fault; a prominent oblique fault that runs from south-west to north-east for over 100 km through Murcia province.
Geological studies have confirmed the importance of this fault as one of the structures controlling crustal shortening as Europe collides with Africa.
The fault can be partitioned into a number of segments, and of these, only the segment close to Lorca appears to be seismically active in historical times.
The shallow depth of the 11 May earthquake, which contributed to the amount of damage caused, and which has been estimated to have been as little as 3.5 km, appears to be typical of the behaviour of the Alhama de Murcia fault .
Earthquakes in the range of 5 to 6 in magnitude have occurred at regular intervals, notably in 1579, 1674, 1783, 1818, 1855 and 1907.
The most recent activity on this fault segment was in 1977 and 1978; however, these earthquakes were only around magnitude 4.
The earthquake of 28 August 1674 appears to have been the strongest of those in the historical record, with a magnitude close to 6. It caused considerable damage, and many of the historical buildings in the town today were rebuilt after the 1674 earthquake.
Contact Dr Brian Baptie for further information.