Báo cáo "Some results of discovering old vestiges in the vicinity of Kinh Thien Temple " doc

VNUJournalofScience,EarthSciences23(2007)177‐186 177 Someresultsofdiscoveringoldvestiges inthevicinityofKinhThienTemple VuDucMinh 1 *,NguyenBaDuan 2  1 CollegeofScience,VNU 2 InstituteofGeophysics,VAST Received14June2007 Abstract.Afterreportingtheresults ontheoldroad foundationsaroundDoan Monvestige,apart frominvestigatingtodiscoveroldvestigesinthevicinityofKinhThienTemple,theauthorstryto determine whether these old discovered road foundations still exist and direct from inside Doan MontoKinhThienTempleornot? Theresultsshowthatitcanbeimaginedthatwholeinvestigatedareacanlocateontheflathill, withindicationsofthecultureoftheLeDynastyandoftheTranDynastyatthedepthofabout1m and 2 m. The indications  of old road foundations and old roads are clearly seen. These road foundations and roadshave a directionextended from Doan MonGate to Kinh Thien Temple. In addition, small noticeable abnormal objects have been discovered in the investigated area.  The resultsarereportedinthispaper. Keywords:GPR;MRI;Profile;Antennae;Wavepatterns. 1.Introduction *  A difficult problem of archaeological work isthatinordertodiscoveroldvestigesonehas firsttorelyon signsonthegroundsurfaceand thendoexcavationsbyhanddigging.Thisdoes not always lead to a positive result, and sometimes partly destroys the vestige. On the other hand, if a vestige has been found after digging, its preservation is very difficult, expensive,andloweffective. Nowadays, geophysical archaeological methods have been successfully used  in the world for the purpose of discovering, locating and mapping archaeological objects buried in _______ * Correspondingauthor.Tel.:84‐4‐8587781. E‐mail:minhvd@vnu.edu.vn the ground. Among those, the Multi‐electrode ResistivityImaging(MRI)method[1,3]andthe Ground‐PenetratingRadar(GPR)[2,3]method arenearearthsurfac eon es,wh ichareconsidered  asthemainmethods. In Vietnam, geophysicists start to pay attentiontothisproblem,especiallyleadersand managershavebeenallowed tousegeophysical methodsintheworktodiscoveroldvestigesin order not to destroy the scene as well as the vestiges, to help the archaeologists to see overall picture of the area under investigation, andhencetodigonlynecessaryvestiges. This paper presents some results of discovering old vestigesin thevicinity of Kinh ThienTempleusingabove‐mentionedmethods. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 178 2.Featuresoftheareaunderinvestigationand fieldmethods Atpresent,theKinhThienTempleareaand its vicinity (Fig. 1) have many houses in use. Apart from these houses, internal roads are concretedorasphalted.Therearenoanysignof theoldvestigesonthegroundsurface. However, above Kinh Thien Temple, according to historical data, there is a house which was built a long  time ago and has been restored. Below the King’s yard, there are two stonedragonswithheadsalongthenorth‐south direction. BehindthehousesN6andN18tothesouth isDoan Monvestige.TheArchaeologicalInstitute and Department of Culture and Information of Hanoi have made archaeological excavations inside Doan Mon vestige. They have found a yard coveredby the brick, stone jetty ofthe Le Dynasty at the depth of 1‐1.2m, a 1.3m‐wide roadoftheTranDynasty coveredbythelemon flower‐colorbrickatthedepthof1.9‐2m,below itthe roadfoundationsoftheLy Dynasty have been found. In previous research on the area around Doan Mon [3], we have discovered these old road foundations behind Doan Mon vestige.Therefore,apartfromourinvestigation  in order to discover old vestiges in the Kinh Thien Temple area, we want to determine whether these old road foundations still exist and direct from inside the Doan Mon to the KinhThienTempleornot? We used two geophysical methods: GPR and MRI. The measuring profiles have been arranged so that they are co inciding with or  perpendicular to  the directions of old road foundations found inside Doan Mon vestige, fromDoanMongatetotheKing’syardofKinh Thien Temple, with two areas: area 1 between Kinh Thien Temple and house N15, area 2 between houses N16, N17,  N6 and N18. In these profiles, the MRI measuring profile with distanceof1mbetweentheelectrodesisprofile DIEN‐2 just in front of house N15 and the King’syardandaplentyoftheGPRmeasuring profiles with antennae of 80 MHz (denoted as 80,forexample80D11),200MHz(denotedas2, for example 2D4) and 400 MHz (denoted as 4,  forexamp le4TEST1).Theseprofilesar epresented inFig.1. 3.Resultsofanalysis 3.1.AreabetweenhousesN16,N17,N6,andN18 In this area, we have made seven GPR measuringprofileswithantennaeof 80,200and 400 MHz. Among these profiles, five profiles directedfrom Eastto West(profiles 80N30 and 4TEST1, which coincide with each other) and two profiles directed from the south to the north,whichcoincidewitheachotherbuthave different depths. Due to technical reason, MRI measurementshave notbeencarriedout(Fig.1). Fig.2showstheresultsofanalysisforthree GPR profiles measured by 80 MHz antenna. In the wave pattern of these profiles, a sign of foundat ionlayersisnotseenbecausewavelength  of the 80 MHz antenna is large (about 1.25 m) and,consequently, manyobjectsofsmallersize areneglected.However,from2Djoinedpicture andwavepatternsweobserveratherclearlythe geologicalstructureofthisarea(probablyitisa broadandnothighhill). Comparing the results of the GPR sections of two coinciding GPR profiles 80D9N and 80D9N2 having different depths (Fig. 3), one can see that geological structure signs along these profiles coincide with each other and are atsmalldepth(about2.5m)inthebeginningof theprofiles. Fig.4presentstheresultsoftheGPRsections with200MHzand400MHzantennae.Allthree GPR  sections show similar characteristics, namely many abnormal objects and strong VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 179 reflectingborders.Asignoffoundationlayerat 1mdepthexistbutnotclearly;foundationlayer at2mdepthisratherclearlyseenontheprofile 2TEST1but not clearlyonother profilesdueto distanceisnotdeepenough.Intheendingpart of the profiles  (closed to house N17 in the scheme), there are strong reflecting geological borders at small depth (only  about 1.5 m) sloping to the beginning of the profiles. This canbeavestigeofahillarea.Itiscoveredbya filledlandaffectedbyhumanactivities. Especially, on two GPR sections 4TEST2 and  4TEST1 there is a sign of a road of the Le Dynasty, on both sides of which there are two stone jetties, in particular clear on the GPR section 4TEST2, in the middle of which we observe multiple reflections since radar waves beatatstrongreflectingobjects(brick,sto n e et c. ). This sign is clearly seen in Fig. 5. However, these two profiles are about 10 m apart but distance between two stone jetties is changed? On the GPR section 4TEST2 it is from distance at 5.5 to 10 m (4.5 m), on the GPR section 4TEST1fromdistanceat6.5to 9.5m(3m).This problem should be clarified in the next investigation.  Fig.1.Positionschemeofgeophysicalinvestigationprofiles. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 180  Fig.2.Wavepatternsand2Djoinedpicturesof80MHz‐antennaprofiles: twoprofiles80N31,80N30andoneprofile80D9N2.  Fig.3.ComparisonoftheresultsoftheGPRsectionsoftheprofiles80D9N2(above) and80D9N(below)coincidingwitheachotherbutwithdifferentdepths. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 181  Fig.4.Wavepatternsandresultsofanalysisforprofiles2TEST1(above),4TEST2(middle)and4TEST1(below). 3.2. Area in the front of the King’s yard of Kinh ThienTemple Inthisarea,wehavemade4GPRmeasuring profiles with antennae of 80 MHz, 200 MHz and one MRI profile (DIEN‐2). Among those, profiles 80D11 and 2D4 coincide with each other, in front of the King’s  yard; the profiles 80D12and2D5coincidewitheachot her,infront of the yard of house N15 and nearly coincide with the profile DIEN‐2. These profiles direct from the east gate to the west gate (Fig. 1), or fromtherighttotheleftinwavepatterns. In the wave pattern of the GPR measuring profileswithantennaeof200MHz(Fig.6),one can see two foundation layers at the depth of about1mand2m,existingfromthebeginning to the end of the profiles. Probably these two foundation layers are related to the culture  of the Le Dynasty and the Tran Dynasty. On the GPRsection2D5(infront ofhouseN15) asign of 2m‐foundation layer is weaker; on the GPR section 2D4 (in front of the King’s yard), this foundation layer is clearer and somewhat sloping to east. On both profiles, abnormal objectsarediscovered.OntheGPRsection2D4, there are several strong reflections at distance of 11‐24 m (in the part in front of the King’s yard)from groundsurfacetothedepthof1.7m. This can be due to multiple reflections from terraces in front of the  King’s yard under ground.OntheGPRsection2D5,therearetwo regionsatdistanceof4‐10mand15‐20m,atthe VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 182 depth of 0.5‐1.2 m in which an indication of inhomogeneousenvironmentexists. Especially, betweenthesetworeg ions(atdistanceof10‐15m) thereare verystrong reflectionsatthedepth of 1.2mandbelow.Thesemaybereflectionsfrom aflagstoneorfromratherthickconcrete. Fig. 7 presents a comparison of two wave patterns of the same profile2D5 but measured by RAMAC equipment with 500 MHz antenna and by SIR 10B equipment with 200 MHz antenna. One can see two inhomogeneous regionson both sides andone strongreflecting anomaly in the middle of which have  rather clear and coinciding indications. One can observe indicationofthisanomalyinthewave pattern of profile 80D12 (Fig. 8) and pseudoresistivitycross‐section(Fig.9). In the wave pattern of the GPR profiles (80D12 and 80D11) with antennae of 80 MHz (Fig. 8) indications of foundation layers and of someabnormalobjectsarenotclearbecausethe antennaoflowfrequency(80MHz)isusedand, consequently, many objects with smaller size are neglected. In addition, this type of antenna does not havethe curtain that causes thewave patterns to be strongly perturbed. However, in the wave patterns  some large objects such as geological borders and terraces in front of the King’s yard on profile 80D11 near the King’s yardareindicatedratherclearly. The geological bordersstarttoappearatsmalldepth(about3m) indicatingnon‐flatgeologicalstructures.Itmay be a hill area, which has been leveled or depositedmanytimes.  Fig.5.Wavepatternsand2Djoinedpicturesofprofiles4TEST1and4TEST2. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 183  Fig.6.Wavepatternsandresultsofanalysisforprofiles2D5(above), 2D4(below)and2Djoinedpicture(middle).  Fig.7.Comparisonoftwowavepatternsofprofile2D5:obtainedbyRAMACequipment with500MHzantenna(above)andbySIR10Bequipmentwith200MHzantenna(below). VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 184  Fig.8.Wavepatternsandresultsofanalysisforprofiles80D12(above)and80D11(below).  Fig.9.ComparisonoftheGPRsection2D5(above)andMRIsectionDIEN‐2(below). Fig. 9presents a comparison of GPR section 2D5 (above) and MRI section DIEN‐2 (below). The positions of these two profiles are nearly the same. One can see two inhomogeneous regions on both sides and strong reflecting anomaly in the middle of which described above coincide well with three high ‐resistivity regions on the pseudoresistivity cross‐section. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 185 With the resistivity scale, perhaps anomaly in the middle is concrete. Below this anomaly, there is a low‐resistivity, rather symmetrical region. With these indications, it can  be a reservoir which is made of concrete. Below it, there is a low‐resistivity region, this is the reason of strong diminishing of radar waves, affectingpenetrabilityoftheGPRsignals. 4.Concludingremarks ‐ In the area between housesN16, N17, N6 and N18, results of analysis for the profiles by GPR methods, through 2D joined picture and the wave patterns of 80 MHz‐antenna profiles, allow to observe rather clearly the geological structureat oldtimes.Itcan beaflathill.When measuring by 200 and 400 MHz antennae, results show indications of many abnormal objects and several strong reflection borders, especially the indications of the road of the Le Dynasty, the stone jetties on both sides, the indications of multiple  reflections due to beating of radar waves at strong reflecting objects (brick, stone etc.). The foundation layer atthedepthof2misalsoclearlyseen.Closeto houseN17,thereisageologicalborderofstrong reflections at small depth (only about 1.5 m). Thiscanbea vestigeofahillarea.Itiscovered byafilledlandaffectedbyhumanactivities. ‐InthefrontareaoftheKing’syardofKinh Thien Temple, results of analysis for the  profiles by the GPR methods also show rather clear indications of geological borders, foundation layers on the wave patterns and of terraces in front of the King’s yard on profile 80D11closedtotheKing’syard.Thegeological bordersstart toappe aratsmalldept h(about3m), indicatingnon‐flatgeologicalstructures.Itmay be a hill area, which has been leveled or deposited many times. In  the wave patterns of the 200  MHz antenna profiles, there are two foundationlayersatthedepthofabout1mand 2 m. Probably these two foundation layers are relatedtothecultureoftheLeDynastyandthe Tran Dynasty. On both GPR sections, some abnormalobjectshave alsodiscovered.OnGPR section 2D4 (in the part in front of the King’s yard), there are several strong reflections at distanceof 11‐24 mfromground surfacetothe depth of 1.7 m. This can be due to multiple reflections from terraces in front of the King’s yard under  ground. On GPR section 2D5 (in frontofhouseN15)at thedepthof0. 5‐1.2m,ther e isanindicationofinhomogeneousenvironment. Especially,atdistanceof10‐15mtherearevery strongreflectionsatthedep thof1.2mandbelow. These may be reflections from a flagstone or from rather thick concrete. Comparing GPR section 2D5 and MRI section DIEN‐2 having nearly the same  position, one can see that resultsobtainedbybothmethodsareveryclose toeachother.It canbeexpectedthatanomalyin  themiddleisconcrete.Belowthisanomaly, there is alow‐resistivity,rathersymmetricalregion. ‐ Thus, it can be imagined that whole area under investigation can be located on the flat hill, with indications of the culture of the Le Dynasty and of the Tran Dynasty at the depth of about 1 m and 2 m. The indications of  old  road foundations and old roads are clearly seen. Comparison with our previous results of investigation around Doan Mon vestige shows that these road foundations and roads have a direction extended from Doan Mon Gate to KinhThienTemp le.Inaddition,smallabnormal objectshaveb eendisc overed,whicharescattered ontheprofiles. ‐ Once again, it can be stated that the application of GPR and MRI methods to discoveroldvestigesin the groundin Vietnam isveryfeasibleandeffective.However,inorder toindicateexactlythe positionandstructureof old vestiges, one has to select relevant antennae, to arrange the system of profiles so [...]... method  in the direction  of selecting, improving the electrodes, development  of ways  and  procedure  of data  collection  as  well  as  programs  for  analysis  in order  to  increase  the effectiveness  of this  method  in general  and  of application  of combination  of the GPR  and  improved  MRI  methods  in particular to discover old vestiges.   Acknowledgements  The author  would  like ... Vu Duc Minh, Nguyen Ba Duan / VNU Journal of Science, Earth Sciences 23 (2007) 177‐186  that a 3D picture of the area under investigation  can  be  constructed,  to  determine  exact  wave  propagation  velocity  of the environment  under  investigation,  to  carry  out  measurements  and  investigation in more detail.  ‐  We  have  improved  and  are  continuing  to  improve  the MRI  method  in the ... ‐  the staff  members  of the Institute  for  Conservation  of Monuments and MSc. Do Anh Chung ‐ the staff  of the Centre  for  Termite  Control  Research,  Institute  for  Water  Resources  Research  for  helping us during measurements in the field.  References  [1] Geotomo  Software,  Res2dinv  Manual  Ver.  3.5.4,  Penang, Malaysia, 2004.  [2] N.  Stewart,  H.  Griffiths,  Ground  Penetrating ... Griffiths,  Ground  Penetrating  Radar,  2nd  Edition,  MPG  Books  Limited,  Bodmin,  Cornwall, UK, 2004.  [3] Vu  Duc  Minh,  Nguyen  Ba  Duan,  Application  of methods  of Ground  Penetrating  Radar  and  of Multi‐electrode  Resistivity  Imaging  to  discover  old road foundations around Doan Mon vestige,  VNU  Journal  of Science,  Earth  Sciences  23  (2007)  126.  . Monvestige,apart frominvestigatingtodiscover old vestiges in the vicinity of Kinh Thien Temple, the authorstryto determine whether these old discovered. VNUJournal of Science,EarthSciences23(2007)177‐186 177 Some results of discovering old vestiges in the vicinity of Kinh Thien Temple VuDucMinh 1 *,NguyenBaDuan 2  1 College of Science,VNU 2 Institute of Geophysics,VAST Received14June2007 Abstract.Afterreporting the results