POTENSI LIKUIFAKSI BERDASARKAN NILAI GROUND SHEAR STRAIN (GSS) DI KECAMATAN PRAMBANAN DAN KECAMATAN GANTIWARNO KABUPATEN KLATEN JAWA TENGAH

Abstract

Abstrak Penelitian ini bertujuan untuk mengetahui nilai GSS di Kecamatan Prambanan dan Kecamatan Gantiwarno dan mengetahui potensi likuifaksi berdasarkan nilai GSS di Kecamatan Prambanan dan Kecamatan Gantiwarno. Data mikrotremor diambil di 30 titik pengukuran dengan jarak antar titik 2 km. Data mikrotremor dianalisis dengan menggunakan metode HVSR (Horizontal to Vertical Spectral Ratio) untuk memperoleh nilai amplifikasi predominan dan nilai frekuensi predominan. Hasil penelitian menunjukkan bahwa nilai GSS di Kecamatan Prambanan dan Kecamatan Gantiwarno berkisar 0,01 ×10-2 – 0,25 ×10-2. Potensi likuifaksi di Kecamatan Prambanan dan Kecamatan Gantiwarno relatif rendah dan hanya terjadi di beberapa titik penelitian, di antaranya di Desa Bugisan, Desa Sawit dan Desa Jabung dengan nilai GSS pada masing-masing daerah 0,21 ×10-2, 0,24 ×10-2 dan 0,21 ×10-2. Kata Kunci: Ground Shear Strain, likuifaksi, mikrotremor. Abstract The aims of this research were to determine GSS value and to determine liquefaction potential based on GSS value in Prambanan Subdistrict and Gantiwarno Subdistrict. Microtremor data were measured from 30 locations with distance interval of 2 kilometers. Microtremor data were analyzed using Horizontal to Vertical Spectral Ratio (HVSR) method to get amplification factor and predominant frequency. The result of this research shows that GSS value in Prambanan Subdistrict and Gantiwarno Subdistrict are about 0.01 ×10-2 - 0.25 ×10-2. Liquefaction potential in Prambanan Subdistrict and Gantiwarno Subdistrict are relatively low and only occur at some locations in the research area including Bugisan village, Sawit village and Jabung village with GSS of 0.21 ×10-2, 0.24 ×10-2 and 0.21 ×10-2 respectively. Keywords: Ground Shear Strain, liquefaction, microtremor