Analisis struktur batuan di bawah permukaan kompleks arkeologis situs liyangan menggunakan electrical resistivity tomography dan analytic signal geomagnetik

Abstrak

The Liyangan site is located on the slopes of Mount Sindoro is an ancient residential complex built in a wet area rich in vegetation, fields, and rice fields. Geophysical investigations using the Electrical Resistivity Tomography (ERT) and Analytic Signal Geomagnetic (ASG) methods were carried out in the study area to determine the rock structure below the surface. Electrical Resistivity Tomography (ERT) data shows that archaeological buildings at the Liyangan site are built on rocks with low resistivity values ​​(<100 ohm.m) which are interpreted as alluvial deposits with high water saturation. The depth of this alluvial deposit is detected to vary between 3-16 meters below the surface and there is bedrock under this alluvial deposit in the form of volcanic rock of Mount Sindoro. These results indicate that the Liyangan Site has a fertile area and is rich in water, allowing past civilizations to develop around the site area. Several anomalies suspected to be buried archaeological structures were also detected in the ERT section with moderate to high resistivity values ​​(1000-5000 ohm.m). The ASG data shows that the Liyangan Site area that is currently being revealed has a low to moderate magnetic intensity value range ((-55)-4.4nT), while the suspected buried site building area has a high magnetic intensity value (>22nT). Through the ASG map, two fault structures were also obtained based on the contrast value of the magnetic intensity which are trending southeast – northwest and northeast – southwest.