Two earthquakes have hit Surrey in the space of 10 hours – just a fortnight after the county was shook by three other tremors.
Wednesday’s first earthquake struck Newdigate, near Dorking, at 4.59am, and was initially measured at 1.7-magnitude at a depth of 1km.
At 2.33pm, the British Geological Society (BGS) recorded a second wave of seismic activity, close to the same place.
In a tweet, the BGS said: This is very preliminary but the two new stations (and the surrounding ones) have detected another event in the area at around 13.33 (2.33pm BST).
Magnitude of 2-3 is suggested, but we’ll firm that out as we get more data.
One person who felt the first tremor told the BGS: The noise was a weak thud but the house shook for a second or two.
The two earthquakes come soon after a spate of tremors at the end of June and beginning of July.
The president of the Mole Valley Geological Society told Sky News that despite the large number of earthquakes in Surrey, he has yet to feel the effects of one.
Professor Richard Selley was away from the area for some of the previous events, but has not noticed the small magnitude events at home either.
He said: I have experienced volcanoes erupting, but I am really sad not to have felt an earthquake – perhaps I am not a sensitive person.
He said the spate in Surrey is not unusual, as earthquakes often come in swarms.
Prof Selley added: We have records of some in the North Downs, but these were back in the 12th century. We do not know where the epicentre of them was.
People locally are saying it is the oil companies which have been the issue, but this is nothing to do with hydraulic fracturing.
It is exciting when the magnitude stays below three, at that level people are hardly aware of it, but if they get larger they could get more serious.
Of course, there’s nothing you can do about it.
The large number of earthquakes this year has led the BGS to install new equipment closer to the epicentre.
In a statement, the BGS explained: Earthquakes with magnitudes of 2.7, 2.6, 2.4, and 3.0 ML were detected by the BGS on 1 April, 27 June, 29 June and 5 July 2018, respectively, near Newdigate, Surrey, between Dorking and Crawley. These earthquakes were felt by local residents.
For the Newdigate earthquakes our closest monitoring station was over 50km away, so the errors in our location estimates were several kilometres laterally, and depth could not be accurately calculated.
We’ve installed two additional monitoring stations within 10km of the area of activity. This will improve location and particularly depth determination should more earthquakes occur. It should also mean we can detect smaller events.
(c) Sky News 2018: Two earthquakes hit Surrey in 10 hours just two weeks after three were felt