VNUJournalofScience,EarthSciences23(2007)177‐186 177 Someresultsofdiscoveringoldvestiges inthevicinityofKinhThienTemple VuDucMinh 1 *,NguyenBaDuan 2 1 CollegeofScience,VNU 2 InstituteofGeophysics,VAST Received14June2007 Abstract.Afterreportingtheresults ontheoldroad foundationsaroundDoan Monvestige,apart frominvestigatingtodiscoveroldvestigesinthevicinityofKinhThienTemple,theauthorstryto determine whether these old discovered road foundations still exist and direct from inside Doan MontoKinhThienTempleornot? Theresultsshowthatitcanbeimaginedthatwholeinvestigatedareacanlocateontheflathill, withindicationsofthecultureoftheLeDynastyandoftheTranDynastyatthedepthofabout1m and 2 m. The indications of old road foundations and old roads are clearly seen. These road foundations and roadshave a directionextended from Doan MonGate to Kinh Thien Temple. In addition, small noticeable abnormal objects have been discovered in the investigated area. The resultsarereportedinthispaper. Keywords:GPR;MRI;Profile;Antennae;Wavepatterns. 1.Introduction * A difficult problem of archaeological work isthatinordertodiscoveroldvestigesonehas firsttorelyon signsonthegroundsurfaceand thendoexcavationsbyhanddigging.Thisdoes 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,andloweffective. Nowadays, geophysical archaeological methods have been successfully used in the world for the purpose of discovering, locating and mapping archaeological objects buried in _______ * Correspondingauthor.Tel.:84‐4‐8587781. E‐mail:minhvd@vnu.edu.vn the ground. Among those, the Multi‐electrode ResistivityImaging(MRI)method[1,3]andthe Ground‐PenetratingRadar(GPR)[2,3]method arenearearthsurfac eon es,wh ichareconsidered asthemainmethods. In Vietnam, geophysicists start to pay attentiontothisproblem,especiallyleadersand managershavebeenallowed tousegeophysical methodsintheworktodiscoveroldvestigesin order not to destroy the scene as well as the vestiges, to help the archaeologists to see overall picture of the area under investigation, andhencetodigonlynecessaryvestiges. This paper presents some results of discovering old vestigesin thevicinity of Kinh ThienTempleusingabove‐mentionedmethods. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 178 2.Featuresoftheareaunderinvestigationand fieldmethods Atpresent,theKinhThienTempleareaand its vicinity (Fig. 1) have many houses in use. Apart from these houses, internal roads are concretedorasphalted.Therearenoanysignof theoldvestigesonthegroundsurface. 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 stonedragonswithheadsalongthenorth‐south direction. BehindthehousesN6andN18tothesouth isDoan Monvestige.TheArchaeologicalInstitute and Department of Culture and Information of Hanoi have made archaeological excavations inside Doan Mon vestige. They have found a yard coveredby the brick, stone jetty ofthe Le Dynasty at the depth of 1‐1.2m, a 1.3m‐wide roadoftheTranDynasty coveredbythelemon flower‐colorbrickatthedepthof1.9‐2m,below itthe roadfoundationsoftheLy 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,apartfromourinvestigation 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 KinhThienTempleornot? 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, fromDoanMongatetotheKing’syardofKinh 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 distanceof1mbetweentheelectrodesisprofile DIEN‐2 just in front of house N15 and the King’syardandaplentyoftheGPRmeasuring profiles with antennae of 80 MHz (denoted as 80,forexample80D11),200MHz(denotedas2, for example 2D4) and 400 MHz (denoted as 4, forexamp le4TEST1).Theseprofilesar epresented inFig.1. 3.Resultsofanalysis 3.1.AreabetweenhousesN16,N17,N6,andN18 In this area, we have made seven GPR measuringprofileswithantennaeof 80,200and 400 MHz. Among these profiles, five profiles directedfrom Eastto West(profiles 80N30 and 4TEST1, which coincide with each other) and two profiles directed from the south to the north,whichcoincidewitheachotherbuthave different depths. Due to technical reason, MRI measurementshave notbeencarriedout(Fig.1). Fig.2showstheresultsofanalysisforthree GPR profiles measured by 80 MHz antenna. In the wave pattern of these profiles, a sign of foundat ionlayersisnotseenbecausewavelength of the 80 MHz antenna is large (about 1.25 m) and,consequently, manyobjectsofsmallersize areneglected.However,from2Djoinedpicture andwavepatternsweobserveratherclearlythe geologicalstructureofthisarea(probablyitisa broadandnothighhill). 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 atsmalldepth(about2.5m)inthebeginningof theprofiles. Fig.4presentstheresultsoftheGPRsections with200MHzand400MHzantennae.Allthree GPR sections show similar characteristics, namely many abnormal objects and strong VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 179 reflectingborders.Asignoffoundationlayerat 1mdepthexistbutnotclearly;foundationlayer at2mdepthisratherclearlyseenontheprofile 2TEST1but not clearlyonother profilesdueto distanceisnotdeepenough.Intheendingpart 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 canbeavestigeofahillarea.Itiscoveredbya filledlandaffectedbyhumanactivities. 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 beatatstrongreflectingobjects(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 4TEST1fromdistanceat6.5to 9.5m(3m).This problem should be clarified in the next investigation. Fig.1.Positionschemeofgeophysicalinvestigationprofiles. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 180 Fig.2.Wavepatternsand2Djoinedpicturesof80MHz‐antennaprofiles: twoprofiles80N31,80N30andoneprofile80D9N2. Fig.3.ComparisonoftheresultsoftheGPRsectionsoftheprofiles80D9N2(above) and80D9N(below)coincidingwitheachotherbutwithdifferentdepths. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 181 Fig.4.Wavepatternsandresultsofanalysisforprofiles2TEST1(above),4TEST2(middle)and4TEST1(below). 3.2. Area in the front of the King’s yard of Kinh ThienTemple Inthisarea,wehavemade4GPRmeasuring 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 80D12and2D5coincidewitheachot her,infront 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 fromtherighttotheleftinwavepatterns. In the wave pattern of the GPR measuring profileswithantennaeof200MHz(Fig.6),one can see two foundation layers at the depth of about1mand2m,existingfromthebeginning 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 GPRsection2D5(infront ofhouseN15) asign 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 objectsarediscovered.OntheGPRsection2D4, there are several strong reflections at distance of 11‐24 m (in the part in front of the King’s yard)from groundsurfacetothedepthof1.7m. This can be due to multiple reflections from terraces in front of the King’s yard under ground.OntheGPRsection2D5,therearetwo regionsatdistanceof4‐10mand15‐20m,atthe VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 182 depth of 0.5‐1.2 m in which an indication of inhomogeneousenvironmentexists. Especially, betweenthesetworeg ions(atdistanceof10‐15m) thereare verystrong reflectionsatthedepth of 1.2mandbelow.Thesemaybereflectionsfrom aflagstoneorfromratherthickconcrete. Fig. 7 presents a comparison of two wave patterns of the same profile2D5 but measured by RAMAC equipment with 500 MHz antenna and by SIR 10B equipment with 200 MHz antenna. One can see two inhomogeneous regionson both sides andone strongreflecting anomaly in the middle of which have rather clear and coinciding indications. One can observe indicationofthisanomalyinthewave pattern of profile 80D12 (Fig. 8) and pseudoresistivitycross‐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 someabnormalobjectsarenotclearbecausethe antennaoflowfrequency(80MHz)isusedand, consequently, many objects with smaller size are neglected. In addition, this type of antenna does not havethe curtain that causes thewave 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 yardareindicatedratherclearly. The geological bordersstarttoappearatsmalldepth(about3m) indicatingnon‐flatgeologicalstructures.Itmay be a hill area, which has been leveled or depositedmanytimes. Fig.5.Wavepatternsand2Djoinedpicturesofprofiles4TEST1and4TEST2. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 183 Fig.6.Wavepatternsandresultsofanalysisforprofiles2D5(above), 2D4(below)and2Djoinedpicture(middle). Fig.7.Comparisonoftwowavepatternsofprofile2D5:obtainedbyRAMACequipment with500MHzantenna(above)andbySIR10Bequipmentwith200MHzantenna(below). VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(2007) 177‐186 184 Fig.8.Wavepatternsandresultsofanalysisforprofiles80D12(above)and80D11(below). Fig.9.ComparisonoftheGPRsection2D5(above)andMRIsectionDIEN‐2(below). Fig. 9presents 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. VuDucMinh,NguyenBaDuan/VNUJournalofScience,EarthSciences23(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, affectingpenetrabilityoftheGPRsignals. 4.Concludingremarks ‐ In the area between housesN16, 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 structureat oldtimes.Itcan beaflathill.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 atthedepthof2misalsoclearlyseen.Closeto houseN17,thereisageologicalborderofstrong reflections at small depth (only about 1.5 m). Thiscanbea vestigeofahillarea.Itiscovered byafilledlandaffectedbyhumanactivities. ‐InthefrontareaoftheKing’syardofKinh 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 80D11closedtotheKing’syard.Thegeological bordersstart toappe aratsmalldept h(about3m), indicatingnon‐flatgeologicalstructures.Itmay 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 foundationlayersatthedepthofabout1mand 2 m. Probably these two foundation layers are relatedtothecultureoftheLeDynastyandthe Tran Dynasty. On both GPR sections, some abnormalobjectshave alsodiscovered.OnGPR section 2D4 (in the part in front of the King’s yard), there are several strong reflections at distanceof 11‐24 mfromground surfacetothe 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 frontofhouseN15)at thedepthof0. 5‐1.2m,ther e isanindicationofinhomogeneousenvironment. Especially,atdistanceof10‐15mtherearevery strongreflectionsatthedep thof1.2mandbelow. 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 resultsobtainedbybothmethodsareveryclose toeachother.It canbeexpectedthatanomalyin themiddleisconcrete.Belowthisanomaly, there is alow‐resistivity,rathersymmetricalregion. ‐ 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 KinhThienTemp le.Inaddition,smallabnormal objectshaveb eendisc overed,whicharescattered ontheprofiles. ‐ Once again, it can be stated that the application of GPR and MRI methods to discoveroldvestigesin the groundin Vietnam isveryfeasibleandeffective.However,inorder toindicateexactlythe positionandstructureof 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. . Monvestige,apart frominvestigatingtodiscover old vestiges in the vicinity of Kinh Thien Temple, the authorstryto determine whether these old discovered. VNUJournal of Science,EarthSciences23(2007)177‐186 177 Some results of discovering old vestiges in the vicinity of Kinh Thien Temple VuDucMinh 1 *,NguyenBaDuan 2 1 College of Science,VNU 2 Institute of Geophysics,VAST Received14June2007 Abstract.Afterreporting the results