Cheetham, Paul

Murphy, James

English

Bournemouth University Research Online

A Comparative Study into the Effectiveness of Geophysical Techniques forthe Location of Buried Handguns.James  Murphy1 and Paul Cheetham2Centre for Forensic SciencesSchool of Conservation SciencesBournemouth UniversityBournemouth, UKBH12 5BB1 email: g7895042@bmth.ac.uk2 email pcheetham@bmth.ac.ukThe proliferation of firearms in the UK, deemed ‘intolerable’ by  Prime  Minister  Gordon  Brownhas been the cause of great concern amongst law enforcement agencies and the increase in firearmrelated homicides by gangs in  inner  city  areas  combined  with  the  recent  large  scale  criminalalteration of replicas into effective firearms justifies this concern. The burying of firearms  for  thepurposes of storage or disposal after criminal activity is much  documented  both  in  the  UK  andabroad  and  the  US  phenomenon  of  ‘block  guns’  or  firearms   buried   strategically   in   gangneighbourhoods for rapid access gives pause for thought.  Consequently,  considering  the  currentgun climate, ascertaining the most effective methods to locate these buried weapons is timely.Much forensic geophysics research that  has  been  published  recently  relates  to  the  location  ofburials, both mass and individual. While this is important there has  been  less  published  researchinto the location of  associated  evidence,  which  may  be  located  in  a  different  location  to  theremains. Previous studies in the location of firearms and  metal  weapons  with  magnetic  locatorsand  metal  detectors  have  been  undertaken,  but  systematic  high  resolution  area  coverage   asfrequently   applied   in   archaeological   geophysical   survey   and   employing   range   sensitivearchaeological grade magnetometry instrumentation has not been thoroughly evaluated.MethodologyIn this study 0.5m and 1.0m fluxgate and 1.0m caesium gradiometer results  were  compared  with500 and 800MHz frequency ground  penetrating  radar  (GPR)  surveys.  The  two  different  high-quality replica handguns employed were buried at two depths (0.30 and 0.50m) both singly and asa cache. The site chosen was a flat grassed area set within an urban environment, the  near-surfacegeology being a uniform sand. The site  contained  significant  amounts  shallow  ferrous  materialwhich was partially cleared by the use of a metal detector prior to the main surveys.Figure 1.  800MHz GPR profile with handgun cache buried at a depth of 0.50m (50cm)ConclusionsOverall, the results from the  magnetic  surveys  were  problematic  with  the  responses  from  theburied handguns difficult  to  distinguish  clearly  from  site  noise.  However,  some  of  the  GPRsurveys proved particularly successful (fig. 1), although the type of  handgun  and  changes  in  theorientation of the guns resulted in significant effects on their delectability.

A Comparative Study into the Effectiveness of Geophysical Techniques for the Location of Buried Handguns

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