Ten seismic events have been detected in the Newdigate, Surrey area of the United Kingdom, between Dorking and Gatwick airports near London, since April 1, 2018. Magnitudes of this cluster of events range from 1.5 to 3.0. There are fears that quakes might be caused by nearby fracking operations.
According to the British Geological Survey (BGS), the ninth and tenth events took place at around 04:00 and 13:30 UTC on July 18 with magnitudes of 2.0ML and 2.6ML, respectively. The quakes hit at a shallow depth between 500 m (1 640 feet) and 2 km (1.2 miles).
Dr. Stephen Hicks from Southampton University said a 0.4 aftershock had been measured after the second quake.
You might find the attached map interesting, showing the location of recent Surrey Earthquakes (red circles), our two new stations (yellow pins) and from the OGA website the location of nearby boreholes (blue squares). pic.twitter.com/nPbDMTjvp4— BGSseismology (@BGSseismology) July 19, 2018
Yep, so the new seismometers in Surrey are allowing us to detect much smaller quakes. A magnitude 0.4 aftershock occurred secs after yesterday's M1.9 quake. So small it would not have been felt by people. Not an increase in the rate of events - just much better detection now. pic.twitter.com/INVegE2fVo— Stephen Hicks (@seismo_steve) July 19, 2018
Here's an overview showing the locations of the now 10 events in the Surrey earthquake swarm.— Stephen Hicks (@seismo_steve) July 18, 2018
Note that based on today's two quakes, data from the new stations seems to be shifting the location of the cluster a few km to the north. pic.twitter.com/LhHuJkxSjS
I'm briefly quoted in this @BBCNews article summarising the latest quakes in Surrey.— Stephen Hicks (@seismo_steve) July 20, 2018
The CEO of a nearby oil company suggests there is a surface trace of a "large fault" very close to the quake epicentres. But I don't see this fault in the BGS maps ... intriguing ... https://t.co/RQei4O55aC
The strongest quake so far was a M3.0 on July 5. It was felt by more than 800 people who reported it to the BGS.
Residents are expressing fears that quakes are being caused by fracking operations at nearby Horse Hill while oil exploration company UKOG insists that there is no link with the quakes. They claim that work at the site does not involve subsurface drilling and 'so has little to no seismic impact on the surrounding area.'
"We are seeking to better understand what's going on," said BGS seismologist David Galloway.
"We will find out what is the cause. We live on a dynamic planet, but we are looking at the issue of oil exploration in the area to see if it is connected. But it could be entirely natural. Plates move about all the time. They're bashing and moving away from each other."
Further work may be able to determine if any connection exists, BGS said. "As an independent and impartial provider of geospatial data, we hope that our continuing high quality real-time seismic monitoring will produce a comprehensive and open data-set. We will continue to analyze this data as the situation develops allowing us and anyone else to investigate the causal factors of these events."
List of all earthquakes detected by the BGS around the British Isles in the last 50 days can be found at the following link
Featured image credit: Googe/EMSC/TW