PEMETAAN PATAHAN DAERAH SEMBURAN LUMPUR SIDOARJO MENGGUNAKAN METODE TAHANAN JENIS 2-D

Reaktivasi patahan watukosek merupakan salah satu penyebab munculnya semburan lumpur Sidoarjo yang masih diperdebatkan hingga saat ini. Studi yang telah dilakukan sebelumnya menunjukkan adanya manifestasi di permukaan akibat patahan watukosek, contohnya pembelokan geomorfologi Kali Porong, dan orientasi arah patahan yang melewati pusat semburan lumpur Sidoarjo. Metode tahanan jenis 2-D menggunakan penetrasi arus listrik untuk mendapatkan tahanan jenis semu, lalu diinversikan untuk memetakan patahan yang berada di daerah semburan lumpur Sidoarjo. Konfigurasi Wenner-Schlumberger digunakan dengan bentangan 400m hingga 1100m agar mendapatkan kedalaman maksimum hingga ±200m. Data pengukuran di inversi menggunakan RES2DINV dan dipetakan dengan menggunakan ZondRes2D. Anomali patahan yang didapat pada lintasan TG4 memiliki trend sudut kemiringan (dip) ke arah Timur pada kedalaman 90m – 150m yang memotong nilai tahanan jenis tinggi. ==================================================================================================== Watukosek fault reactivation was one of the cause of the mudflow in Sidoarjo mud volcano disaster, which was constantly debated until this day. Studies that had been done previously showed surface manifestation due to Watukosek fault, for example the deflection of Porong river geomorphology, and faults orientation which passed through the center of the mudflow in Sidoarjo. Resistivity cross-section around Sidoarjo mud volcano was acquired from inverted apparent resistivity value, which was recorded from the penetration of electric current into the Earth’s layer. Wenner-Schlumberger configuration was used with 400m until 1100m cable length in order to reach maximum depth of up to ±200m. Measurement data was inversed by using RES2DINV and mapped by using ZondRes2D. Anomalies found on line TG4 with layer dipping to the East at a depth of 90m to 150m bordering between two high resistivity value