ANALISIS KEBERADAAN STRUKTUR CAGAR BUDAYA BAWAH PERMUKAAN BERDASARKAN DATA GEOLISTRIK 2D: STUDI KASUS SITUS KUMITIR, KABUPATEN MOJOKERTO

Sulthan Khalid Siradj, Saptono Budi Samodra S.T., M.Sc.; Muhammad Ichwan S.S., M.A.

2025 | Skripsi | TEKNIK GEOLOGI

Kawasan Trowulan dan sekitarnya di Kabupaten Mojokerto dikenal sebagai pusat peradaban Kerajaan Majapahit. Salah satu situs peninggalan yang berada di kawasan ini adalah Situs Kumitir, yang hingga kini struktur bangunan utamanya masih belum sepenuhnya terungkap. Oleh karena itu, salah satu metode yang dapat digunakan untuk membantu menambah informasi tim arkeolog dalam mengidentifikasi serta menduga letak Struktur Cagar Budaya yang masih terpendam adalah melalui penerapan metode geolistrik 2D menggunakan konfigurasi dipole – dipole. Metode tersebut mampu mengidentifikasi karaktersitik anomali resistivitas Sturktur Cagar Budaya baik dari nilai resistivitas, geometri anomali, hingga sifatnya dengan kondisi sekitarnya. Metode serta konfigurasi ini dipilih karena sensitivitas dan resolusi yang sangat baik dalam mendeteksi variasi resistivitas lapisan lateral bawah permukaan, serta kemampuannya dalam mengidentifikasi litologi. Analisis data dari 5 lintasan geolistrik yang dikorelasikan dengan 19 STA geologi menunjukkan bahwa Struktur Cagar Budaya di Situs Kumitir memiliki karakteristik anomali nilai resistivitas berkisar 12 - 31.2 ohm.meter di lapangan, 15.6 - 82.8 ohm.meter di laboratorium, geometri bentuk persegi panjang, bersifat kontras terhadap lapisan disekitarnya dan tidak menerus. Hal tersebut mengindikasikan potensi keberadaan struktur terpendam pada kedalaman 1 – 2 meter di lintasan 1, 3 - 4, dan 5. Selain itu penampang nilai resistivitas juga merepresentasikan urutan lapisan litologi bawah permukaan dengan baik, meliputi endapan pasir kasar dengan nilai resistivitas 31.2 - 81.2 ohm.meter berwarna hijau terang - gelap, pasir kerakalan dengan nilai resistivitas 81.2 - 341 ohm.meter berwarna kuning - merah, dan endapan pasir berangkalan memiliki nilai resistivitas < 341>

The Trowulan area and its surroundings in Mojokerto Regency are recognized as the cultural center of the Majapahit Kingdom. One of the archaeological remains in this region is the Kumitir Site, whose main structural components have yet to be fully uncovered. To support archaeologists in identifying and estimating the locations of buried cultural heritage structures, a 2D geoelectrical method using dipole–dipole configuration was applied. This method is capable of detecting resistivity anomaly characteristics of cultural structures, including resistivity values, anomaly geometry, and their contrast with surrounding materials. The dipole–dipole configuration was selected due to its high sensitivity and resolution in detecting lateral subsurface resistivity variations and its effectiveness in lithological identification. Data analysis from five geoelectrical lines, correlated with 19 geological observation stations (STA), indicates the presence of resistivity anomalies ranging from 12–31.2 ohm.m in the field and 15.6–82.8 ohm.m in laboratory measurements. These anomalies display rectangular geometries, are discontinuous, and contrast with the surrounding layers, indicating the potential presence of buried structures at depths of 1–2 meters along lines 1, 3, 4, and 5. Furthermore, the resistivity profiles also represent subsurface lithological sequences, including coarse sand deposits (31.2–81.2 ohm.m, light to dark green), gravelly sand (81.2–341 ohm.m, yellow to red), and conglomeratic sand (?341 ohm.m, dark red to purple), confirmed through correlation with stratigraphic profiles at STA 1, 3, 7, 16, and 17. Despite its accuracy in representing lithology, this method has limitations, such as the inability to detect thin tephra intercalations and reduced precision in layer thickness estimation. Nonetheless, the correlation between geoelectrical results and field conditions confirms the effectiveness of the 2D geoelectrical dipole–dipole method in detecting buried cultural heritage structures, although attention should be given to noise sensitivity and the preservation state of the target objects.

Kata Kunci : Situs Kumitir, Struktur Cagar Budaya, karaktersitik anomali resistivitas, geolistrik 2D, konfigurasi dipole – dipole