Correlation of Geophysical Methods to Investigate an Archaeological Site at Bujang Valley, Kedah, Malaysia

An integrated geophysical survey using electrical resistivity tomography (ERT), seismic refraction tomography (SRT) and magnetic techniques was performed with the purpose of locating buried artifacts and defining shallow structures at the Bujang Valley archaeological area, Kedah, Malaysia. Bujang Valley is considered to be the earliest commercial and religious center in Malaysia. The geophysical investigation was conducted in three steps. First, a magnetometry survey was performed using a G-856 proton precession magnetometer over 15 profiles. Then, a resistivity survey was designed in 6 profiles utilizing a pole-dipole array. Later, 2 lines of seismic refraction were measured and correlated with resistivity survey results. The magnetic survey revealed six anomalies which two anomalies had a high magnetic value, related to buried structures. The ERT and SRT techniques displayed three main layers of alluvium soil mixed with sand and clay, saturated zone and the bedrock layer. A joint analysis of results showed that the obtained information well suited to determine the archaeological remains and subsurface geological properties. An excavation test confirmed the geophysical results. Consequently, the results of this study reconfirmed that the integrated geophysical techniques yield satisfactory results and useful information upon which archaeologists can base further investigations of the site.