Friday, May 22, 2015

M4.2 Quake Rattles UK & A Review Of Europe’s Seismic Risks


Credit British Geological Society


# 10,077


Although the risks of seeing a major earthquake in the UK are small, the British Isles are not immune to moderately strong tremors.  Their strongest recorded quake (M6.1) occurred in 1931, well enough offshore into the North Sea as to not cause much damage (see BGS account of the Dogger Bank Earthquake).


Overnight a considerably smaller quake occurred just offshore from Ramsgate, Kent.  The British Geographic Society describes the event as:


The earthquake of the 22 May 2015 occurred at 02:52 BST0 (01:52 UTC), with an epicentre approximately 7 km south of Ramsgate, Kent. The instrumental magnitude was determined at 4.2 ML, and the earthquake was located approximately 24 km northeast of the magnitude 4.3 Folkestone earthquake that occurred on 28 April 2007. So far, over 1,000 felt reports from an automatic online questionnaire survey have been received from members of the public, almost all of them coming from within a 75 km radius of the epicentre, covering Ramsgate and Margate and their surrounding hamlets, as far south as Dover and Folkestone (approximately 18-26 km southwest of the epicentre), Canterbury (approximately 22 km to the west of the epicentre) and Herne Bay (approximately 20 km to the northwest of the epicentre). Further afield, reports have been received from the Faversham, Chatham, Basildon and Southend-on-Sea areas. The most distant reports have been received from Norwich, North Walsham and Cromer (see map).

Almost all of the reports indicated that people were awoken from their sleep. Over half the reports described the shaking strength of the earthquake to be moderate, mainly with a trembling effect, and described the sound strength as moderate. Over two thirds of the reports stated that windows rattled and one third reported furniture shaking. Reports described “thought door to hotel was being kicked in, woke up alarmed”, “woke the whole household and neighbours with a bang that lasted 1-2 seconds”, “walls of house creaked, sounded like heavy object rolling over roof of the house”, “noise and the whole building just shaking the road made a weird loud noise too”, “banging of window shutters first, then rumbling noise faintly but shutter banging became louder, then four poster bed hangings were swaying and whole room seemed to be moving” and “I was lying in my bed watching something with my headphones on when I felt the bed shake”

Updated at 11:30 BST (10:30 UTC), 22 May 2015


This is a region with some history of seismic activity - as the historical map below shows - in 2007 a 4.2 quake was reported just south of last night’s quake, and if you go back to the 1300’s an (estimated) M5.8 quake occurred just offshore.



Historical quakes near Ramsgate, Kent


When it comes to earthquakes we usually think first of the Pacific’s Ring Of Fire, but Europe – particularly southern Europe -  has a long history of destructive quakes as well.   And lest anyone discount the destructiveness of a moderate 6.0 quake, few buildings in northern and central Europe were built with seismic safety in mind.


30,000+ European Quakes Charted – Credit SHARE


In 2011,  in A Look At Europe’s Seismic Risks, we took a look at some of the devastating earthquakes to strike Europe over the past 700 years, including the quake that leveled the Swiss town of Basel in 1356 and the horrific earthquake and tsunami that struck Portugal in 1755 on November 1st (All Saint’s Day).


In December of 2011, in WHO e-Atlas Of Natural Disaster Risks To Europe, we looked at some of the seismic risks to Europe. Also in 2011 (see UNDP: Supercities At Seismic Risk) we saw a report that stated that half of the world’s supercities (urban areas with 2 million – 15 million inhabitants) are at high risk for seismic activity.


And more recently, in January of 2012 (see UN Agency Warns On Global Seismic Risks), the United Nations International Strategy For Disaster Reduction (UNIDSR.Org) issued a cautionary warning about ignoring seismic threats.

Below you’ll find the 2013 SHARE (Seismic Hazard Harmonization in Europe) seismic hazard map.




Last April, in  UK: 2015 Civil Risks Register, we looked at more than 2 dozen serious `risks’ to the UK’s civilian population that the the UK government is actively concerned about, and preparing for. 


They range from catastrophic terrorist attacks to effusive volcanic eruptions (in Iceland) to pandemic influneza (their #1 natural disaster concern).


Last night’s temblor is a reminder that disasters can strike anytime, and anywhere, and preparedness isn’t just for those who live on major fault lines or in the path of hurricanes and typhoons.  Every home should have no less than a 72-hour supply of emergency food and water, a good first aid kit, emergency lighting (not candles!), a battery operated radio, and a disaster plan.



Basic kit : NWS radio, First Aid Kit, Lanterns, Water & Food & cash


For more on preparedness, you may wish to revisit some of these recent blogs:


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